{"gene":"TG_255260","gene_symbol":"AMA1","run_date":"2026-09-08T15:31:41+00:00","timeline":{"discoveries":[{"year":2000,"finding":"TgAMA1 is a type I transmembrane protein that localizes to micronemes in intracellular tachyzoites; upon release of mature tachyzoites, it redistributes predominantly to the apical end of the parasite surface. A ~54 kDa N-terminal cleavage product is constitutively shed into the medium by extracellular parasites. Antiserum against recombinant TgAMA1 blocked invasion by ~40%, and viable TgAMA1 knockout could not be produced, indicating an essential role in invasion.","method":"Immunofluorescence assay, immunoelectron microscopy, Triton X-114 phase partitioning, iodonaphthalene azide labeling, knockout attempt, invasion inhibition assay with antiserum","journal":"Infection and immunity","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (IFA, IEM, biochemical fractionation, functional knockout attempt, invasion inhibition), replicated by multiple subsequent studies","pmids":["11083833"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2000,"finding":"TgAMA1 secretion from micronemes is dramatically enhanced in response to treatments that elevate intracellular calcium levels, consistent with calcium-regulated microneme secretion.","method":"Calcium ionophore/ethanol stimulation assay with immunofluorescence and Western blot monitoring of TgAMA1 release","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct stimulation experiment with biochemical readout, single lab but consistent with broader MIC secretion biology","pmids":["11087913"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2005,"finding":"Conditional depletion of TgAMA1 severely impairs host cell invasion without affecting microneme secretion or initial host cell attachment, but inhibits rhoptry secretion, suggesting TgAMA1 acts after initial attachment to regulate rhoptry discharge.","method":"Regulatable promoter conditional knockout, invasion assay, microneme secretion assay, rhoptry secretion assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional genetic knockout with multiple distinct functional readouts (invasion, microneme secretion, rhoptry secretion), landmark study widely replicated","pmids":["16000372"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]},{"year":2005,"finding":"TgAMA1 associates with a trio of proteins at the moving junction (MJ); at least one of these partners derives from the rhoptry neck (RON proteins), revealing an unexpected collaboration between microneme-derived AMA1 and rhoptry neck proteins at the MJ.","method":"Co-immunoprecipitation, immunoelectron microscopy localizing complex members to the MJ","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP identifying complex plus IEM localization to MJ, independently confirmed by multiple subsequent studies","pmids":["16244709"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2005,"finding":"TgAMA1 is shed from the surface of extracellular tachyzoites via intramembrane cleavage within the luminal half of its transmembrane domain by a rhomboid-like protease, unlike PfAMA1 which is shed by juxtamembrane cleavage. Complete TgAMA1 shedding does not accompany invasion, as intact protein is detected on newly invaded tachyzoites.","method":"Pulse-chase metabolic labeling, inhibitor studies, comparison with Drosophila rhomboid-1 cleavage assay, Western blot of surface protein during invasion","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro rhomboid cleavage assay plus pulse-chase, single study","pmids":["16102004"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2006,"finding":"PfAMA1 co-immunoprecipitates with the Plasmodium falciparum homologue of TgRON4, a rhoptry neck protein, demonstrating that the AMA1–RON4 association is conserved between Toxoplasma and Plasmodium.","method":"Co-immunoprecipitation of native parasite proteins","journal":"Eukaryotic cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP in P. falciparum supporting conservation, single lab","pmids":["16835460"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"finding":"The rhoptry neck proteins RON2, RON4, RON5, and RON8 form a complex that is exported to the host cell membrane during invasion, where RON4/5/8 associate with the cytoplasmic face, while AMA1 is inserted into the parasite membrane. RON2 and AMA1 can interact in the absence of other MJ members, and all MJ proteins undergo proteolytic maturation during trafficking to their organelles.","method":"Metabolic labeling, immunoprecipitation, differential permeabilization with digitonin/saponin, antibody loading into host cell, immunofluorescence","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal biochemical methods establishing topology and pairwise interactions, replicated across labs","pmids":["19247437"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2009,"finding":"An invasion-inhibitory anti-PfAMA1 monoclonal antibody (mAb 4G2) cannot bind PfAMA1 when PfAMA1 is in complex with its RON partners; a single conserved residue Tyr251 in PfAMA1, located in the hydrophobic groove, is required for complex formation, suggesting mAb 4G2 inhibits invasion by blocking PfAMA1–RON interaction.","method":"Antibody competition assay, site-directed mutagenesis of PfAMA1 Tyr251, co-immunoprecipitation","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis plus binding assay, single study in P. falciparum","pmids":["19165323"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"finding":"Conditional overexpression of a catalytically inactive TgROM4 (rhomboid 4) caused a profound block in parasite replication that was completely rescued by expression of the cleaved cytoplasmic tail of TgAMA1 or PfAMA1, revealing that intramembrane cleavage of AMA1 by ROM4 and subsequent release of its cytoplasmic tail triggers the parasite's switch from an invasive to a replicative mode.","method":"Conditional overexpression of dominant-negative TgROM4, rescue with AMA1 cytoplasmic tail expression constructs, replication assay","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — genetic rescue experiment with defined molecular construct, published in Science; however a 2025 erratum (PMID 41379978) was issued for this paper, slightly reducing confidence","pmids":["21205639","41379978"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"finding":"The 2.0 Å X-ray crystal structure of full-length TgAMA1 ectodomain (domains I, II, III) reveals a central hydrophobic groove framed by conserved residues Trp353, Trp354, and Tyr230 from the DII loop, proposed as the RON2 binding site. The DII loop is 14 residues shorter than in Plasmodium AMA1 homologs and restricts access to the groove.","method":"X-ray crystallography at 2.0 Å resolution","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure with >97.5% of ectodomain modeled, landmark structural paper","pmids":["20304917"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"finding":"TgROM4 processes surface adhesins MIC2, AMA1, and MIC3; its suppression decreases MIC2 release into the supernatant, increases surface expression of adhesins, disrupts the normal apical-posterior gradient needed for efficient gliding motility, and severely impairs invasion. Parasites lacking TgROM4 bind host cells better but fail to apically orient and cannot generate a moving junction.","method":"Conditional knockout (tetracycline-regulatable), surface adhesin immunofluorescence, invasion assay, motility assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional genetic KO with multiple mechanistic readouts across two papers","pmids":["20421941"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"finding":"The C-terminus of TgRON2 contains two short segments (D3 and D4) flanking a hydrophobic stretch that independently bind the ectodomain of TgAMA1. Pre-incubation with D3-GST fusion dramatically reduces invasion but does not prevent rhoptry bulb protein injection, demonstrating that TgRON2's C-terminal region forms the bridge between TgAMA1 and the host cell-associated MJ complex but is not required for rhoptry effector delivery.","method":"Immunofluorescence localization of TgRON2 to MJ, pull-down assays with recombinant RON2 fragments, invasion inhibition assay with D3-GST, evacuole assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (pull-down, localization, functional inhibition with defined peptide, evacuole assay), single lab","pmids":["21347354"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"finding":"RON2 is inserted as an integral membrane protein in the host cell, and the region of RON2 that binds AMA1 was defined using multiple interaction assays. Recombinant RON2 protein inhibits invasion of both T. gondii and P. falciparum, demonstrating that the RON2–AMA1 interaction is critical for host cell entry by apicomplexan parasites.","method":"Multiple interaction assays with native and recombinant proteins (pull-down, ELISA-based binding), invasion inhibition with recombinant proteins, differential permeabilization to show RON2 membrane topology","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal binding assays plus functional invasion inhibition in two parasite species","pmids":["21347343"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""},{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"finding":"The 1.95 Å crystal structure of TgAMA1 complexed with a TgRON2 peptide reveals a stepwise assembly mechanism producing an extensive buried surface area, providing structural explanation for how the MJ complex resists mechanical forces during invasion.","method":"X-ray crystallography at 1.95 Å resolution of TgAMA1–RON2 peptide complex","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution co-crystal structure with mechanistic interpretation validated by the interaction biology","pmids":["21778402"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"finding":"In T. gondii tachyzoites, AMA1 is dispensable for normal RON4 ring formation and functional tight junction assembly but enhances tachyzoite apposition to the host cell and increases internalization frequency. In P. berghei sporozoites, only RON4 (not AMA1) is required for hepatocyte invasion, demonstrating RON4 can act independently of AMA1.","method":"Conditional genetic knockdown/knockout of AMA1 and RON4 in T. gondii and P. berghei, invasion assays, immunofluorescence for RON4 ring formation","journal":"Cell host & microbe","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockouts in two parasite species with functional readouts, published in Cell Host & Microbe","pmids":["22177563"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2012,"finding":"Intramembrane proteolysis of TgAMA1 facilitates host cell invasion: parasites expressing an uncleavable TgAMA1(AG/FF+GG/FF) mutant show a growth defect due to impaired invasion, not replication. This refutes the model in which intramembrane cleavage of TgAMA1 regulates replication and instead demonstrates its role is invasion-specific.","method":"Heterologous cleavage assay to characterize transmembrane domain determinants, mutagenesis of TgAMA1 TM domain, complementation of conditional knockout with cleavage-resistant alleles (transgenic and knock-in), growth/invasion assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution plus mutagenesis plus knock-in genetic complementation with quantitative invasion/replication readouts","pmids":["22523242"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2013,"finding":"Plasmodium merozoites and Toxoplasma tachyzoites lacking AMA1 are impaired in host cell attachment but retain normal host cell penetration through the moving junction, indicating AMA1 is a dispensable adhesin rather than an essential invasin for junction-mediated entry.","method":"Genetic deletion of AMA1 in Plasmodium sporozoites, merozoites, and T. gondii tachyzoites; invasion assays distinguishing attachment from penetration","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockouts in three zoite types across two apicomplexan species with dissection of attachment vs. penetration steps","pmids":["24108241"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RH"},{"species":"Plasmodium falciparum","strain":""}]},{"year":2013,"finding":"Toxoplasma sporozoites express paralogues sporoAMA1 and sporoRON2 that localize to the apical region; they interact specifically and exclusively with each other (not with generic AMA1/RON2). Structural studies show sporoRON2 domain 3 binding to sporoAMA1 domains I/II causes major conformational changes allosterically in domain III. Pre-treatment of sporozoites with sporoRON2 domain 3 peptide blocks sporozoite invasion without affecting tachyzoites, and vice versa for generic RON2 domain 3.","method":"Localization by immunofluorescence, pull-down/binding assays for interaction specificity, X-ray crystallography of sporoAMA1–sporoRON2 complex, invasion inhibition assays","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — crystallography plus binding assays plus functional invasion inhibition with stage-specific peptides","pmids":["23940612"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"finding":"Disruption of the AMA1 gene in T. gondii results in upregulation of AMA1 and RON2 homologues (paralogs) that cooperate to support residual invasion, demonstrating molecular plasticity in MJ architecture. AMA1 interacts with RON2 to maintain MJ structural integrity and is required for parasite internalization.","method":"Reverse genetics (AMA1 gene disruption), conditional complementation, immunofluorescence, invasion assays, Western blot for paralog upregulation","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — reverse genetics with multiple functional readouts plus discovery of compensatory paralog upregulation","pmids":["24934579"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"finding":"ALD (fructose-1,6-bisphosphate aldolase) binds the TgAMA1 cytoplasmic tail in vitro, but TgAMA1 cytoplasmic tail mutations that disrupt ALD binding in vitro show no correlation with host cell invasion in vivo. ALD knockout parasites show normal gliding and invasion in glucose-free medium, indicating ALD is not functionally essential for the adhesin-motor linkage and TgAMA1–aldolase interaction is dispensable for invasion.","method":"In vitro binding assay (cytoplasmic tail–aldolase), site-directed mutagenesis, ALD conditional depletion/knockout, invasion assay, gliding motility assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution plus mutagenesis plus genetic KO with multiple functional readouts; importantly establishes a NEGATIVE mechanistic finding (aldolase binding dispensable)","pmids":["24550496"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"finding":"TgAMA1 is palmitoylated; blocking AMA1 palmitoylation enhances the release of AMA1 and other invasion-related proteins from apical secretory organelles (micronemes), suggesting palmitoylation regulates AMA1 retention/secretion from micronemes.","method":"Chemical proteomics (acyl-RAC capture for palmitoylated proteins), palmitoylation site mutagenesis, microneme secretion assay","journal":"Cell host & microbe","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — chemical proteomics plus mutagenesis/functional secretion assay, single lab","pmids":["26468752"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"finding":"The DII loop of TgAMA1 acts as a structural gatekeeper governing ligand binding selectivity in the hydrophobic groove: deletion of the mobile DII loop portion (TgAMA1ΔDIIloop) allows high-affinity binding of an Eimeria tenella RON2 peptide (EtRON2) that normally binds with only weak affinity, while the crystal structure of TgAMA1ΔDIIloop–EtRON2 reveals spatially distinct anchor points in the AMA1 groove.","method":"Isothermal titration calorimetry with RON2 peptide panel, engineering of DII loop deletion mutant, X-ray crystallography of complex","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Strong — ITC binding measurements, mutagenesis, and crystal structure in one study","pmids":["25955165"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"finding":"ROM4 and ROM5 both contribute to intramembrane cleavage (MPP1 activity) of AMA1 in T. gondii: ROM4 KO reduces but does not abolish AMA1 cleavage, while ROM5 accounts for residual AMA1 cleavage in the absence of ROM4 and can also cleave other AMA family members.","method":"Cre-recombinase and CRISPR-Cas9 knockouts of ROM4 and ROM5, Western blot for AMA1 cleavage products, invasion and motility assays","journal":"Molecular microbiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — double genetic knockouts with molecular readout of cleavage products, two-gene epistasis","pmids":["25846828"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2016,"finding":"Binding of TgRON2 D3 peptide to TgAMA1 protects TgAMA1 from rhomboid-mediated cleavage, thereby stabilizing the AMA1-host cell interaction at the moving junction. TgRON2 D3 binding also reduces phosphorylation of Ser527 on the TgAMA1 cytoplasmic tail; parasites expressing a phosphomimetic S527D TgAMA1 allele show an invasion defect, indicating outside-in signaling through the AMA1–RON2 interaction modulates invasion.","method":"Rhomboid cleavage assay with and without D3 peptide, phosphorylation analysis by mass spectrometry, transgenic complementation with phosphomimetic and phospho-null AMA1 alleles, invasion assays with hypercleavable AMA1 variants","journal":"mBio","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — cleavage protection assay, MS-based phosphorylation analysis, and allele-replacement genetics with invasion readout in one study","pmids":["27624124"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"finding":"Conserved aliphatic residues (valine at position +3 of proM2AP, leucine at position +1 of proMIC5) in MIC propeptides are required for microneme targeting; the AMA1 propeptide contains valine/leucine near its N-terminus and mutagenesis of these residues impairs trafficking of AMA1 to micronemes.","method":"N-terminal deletion and mutagenesis of propeptide domains, GFP reporter trafficking assays, cross-species propeptide swap experiments","journal":"Traffic (Copenhagen, Denmark)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutagenesis with trafficking readout, single lab; AMA1 finding is part of broader MIC propeptide study","pmids":["21438967"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"finding":"TgAMA1 lacks targeting information within its C-terminal cytoplasmic domain for microneme trafficking; it can bind aldolase in vitro, and residues responsible for aldolase binding are essential for TgAMA1 function during invasion (at the time of this study, before the later genetic evidence refuted aldolase's functional role).","method":"C-terminal domain truncation/mutation, trafficking assays, aldolase binding assay in vitro, invasion complementation assay","journal":"Molecular microbiology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, and the aldolase-binding-essential-for-invasion claim was subsequently refuted by Shen & Sibley 2014 (PMID 24550496)","pmids":["20545864"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"finding":"Bradyzoites invade host cells in an MJ-dependent fashion using AMA2 and AMA4 (paralogs of AMA1) rather than AMA1 itself. AMA4 plays a key role in cyst burden during chronic infection onset while being dispensable for the acute phase. AMA1-RON2 immunization provides strong protection against both acute and chronic infection.","method":"Immunofluorescence localization in bradyzoites, genetic knockout of AMA4, cyst burden quantification, mouse vaccination/challenge experiments","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with stage-specific functional readouts plus localization data distinguishing stage-specific MJ composition","pmids":["36693095"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"TgAMA1 is a calcium-regulated microneme transmembrane protein that is secreted onto the parasite surface during invasion, where it functions as an adhesin by binding TgRON2 (inserted into the host cell membrane by rhoptry secretion) via a hydrophobic groove in its ectodomain, forming the core of the moving junction complex; this interaction protects AMA1 from constitutive rhomboid (ROM4/ROM5) intramembrane cleavage and triggers outside-in dephosphorylation of its cytoplasmic tail (Ser527), collectively promoting efficient parasite internalization, while the cytoplasmic tail released after cleavage also signals the parasite's switch to replication mode, and palmitoylation of AMA1 regulates its retention/secretion from micronemes."},"narrative":{"mechanistic_narrative":"TgAMA1 is a calcium-regulated type I transmembrane microneme protein of apicomplexan parasites that functions as the parasite-side adhesin at the moving junction (MJ), the ring-shaped structure through which the parasite penetrates its host cell [PMID:11083833, PMID:11087913, PMID:16244709]. Following calcium-triggered microneme secretion, AMA1 relocates to the apical parasite surface, where its ectodomain binds the C-terminal region of the rhoptry neck protein RON2, which is itself inserted into the host cell membrane as part of a RON2/4/5/8 complex [PMID:16244709, PMID:19247437, PMID:21347354, PMID:21347343]. High-resolution crystallography defines the interaction: RON2 docks into a central hydrophobic groove of the AMA1 ectodomain, framed by conserved Trp/Tyr residues and gated by the mobile DII loop, forming an extensively buried, mechanically stable interface that anchors the junction against the forces of invasion [PMID:20304917, PMID:21778402, PMID:25955165]. Conditional depletion and genetic knockout studies place AMA1's function after initial attachment: it promotes tight apposition to the host cell and efficient internalization and contributes to rhoptry discharge, but junction assembly and penetration can proceed at reduced efficiency in its absence, in part through compensatory upregulation of AMA/RON paralogs — establishing AMA1 as a critical but non-obligatory adhesin rather than an essential invasin [PMID:16000372, PMID:22177563, PMID:24108241, PMID:24934579]. AMA1 is subject to constitutive intramembrane cleavage within its transmembrane domain by the rhomboid proteases ROM4 and ROM5, and RON2 binding protects AMA1 from this cleavage while triggering outside-in dephosphorylation of Ser527 in its cytoplasmic tail; genetic evidence with cleavage-resistant and phosphomimetic alleles shows this regulated proteolysis and phosphorylation are tuned specifically to promote invasion [PMID:16102004, PMID:25846828, PMID:27624124, PMID:22523242]. Palmitoylation regulates AMA1 retention and secretion from micronemes [PMID:26468752]. The AMA1–RON2 system is conserved across apicomplexans and diversified into stage-specific paralog pairs — sporozoites use sporoAMA1/sporoRON2 and bradyzoites use AMA2/AMA4 — and AMA1–RON2 immunization confers protection against acute and chronic infection [PMID:16835460, PMID:21347343, PMID:23940612, PMID:36693095].","teleology":[{"year":2000,"claim":"Establishing whether AMA1 is essential for invasion and where it acts defined it as an apically-delivered, invasion-critical microneme protein whose secretion is calcium-controlled.","evidence":"IFA/IEM localization, biochemical fractionation, failed knockout, and antiserum invasion inhibition in T. gondii tachyzoites, plus calcium-ionophore secretion assays","pmids":["11083833","11087913"],"confidence":"High","gaps":["Molecular partner at the parasite surface not yet identified","Mechanistic step of invasion controlled by AMA1 unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2005,"claim":"Conditional depletion pinpointed AMA1's action to after attachment — it is required for efficient invasion and rhoptry discharge but not microneme secretion or initial attachment.","evidence":"Regulatable-promoter conditional knockout with separate invasion, microneme, and rhoptry secretion assays in T. gondii RH","pmids":["16000372"],"confidence":"High","gaps":["How AMA1 links to rhoptry discharge machinery unknown","Direct binding partner not yet defined"],"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]},{"year":2005,"claim":"Identifying AMA1 in a complex with rhoptry neck (RON) proteins at the moving junction revealed the unexpected microneme–rhoptry collaboration that builds the invasion junction.","evidence":"Co-immunoprecipitation and immunoelectron microscopy localizing complex members to the MJ in T. gondii","pmids":["16244709"],"confidence":"High","gaps":["Precise RON partner engaging AMA1 directly not defined","Membrane topology of the complex unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2005,"claim":"Characterizing AMA1 shedding showed it is cleaved by a rhomboid-like protease within its transmembrane domain, and that intact protein persists on newly invaded parasites — distinguishing it mechanistically from PfAMA1.","evidence":"Pulse-chase labeling, protease inhibitor studies, and heterologous Drosophila rhomboid cleavage assay in T. gondii","pmids":["16102004"],"confidence":"Medium","gaps":["Which endogenous rhomboid(s) cleave AMA1 not identified","Functional consequence of cleavage unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2006,"claim":"Demonstrating PfAMA1–PfRON4 co-precipitation established that the AMA1–RON association is conserved across apicomplexan parasites.","evidence":"Co-immunoprecipitation of native proteins in Plasmodium falciparum","pmids":["16835460"],"confidence":"Medium","gaps":["Direct vs. indirect nature of AMA1–RON4 contact unresolved","Structural basis not addressed"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"claim":"Resolving MJ topology showed RON2/4/5/8 are exported to the host membrane with RON4/5/8 on the cytoplasmic face while AMA1 sits in the parasite membrane, and that AMA1 pairs directly with RON2 independently of the other RONs.","evidence":"Metabolic labeling, immunoprecipitation, differential permeabilization, and antibody loading into host cells in T. gondii","pmids":["19247437"],"confidence":"High","gaps":["Region of RON2 binding AMA1 not yet mapped","Structural interface undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2009,"claim":"Mapping the invasion-blocking mAb 4G2 epitope to the PfAMA1 hydrophobic groove (requiring Tyr251) showed that the RON-binding groove is the functional target of inhibitory antibodies.","evidence":"Antibody competition, site-directed mutagenesis of PfAMA1 Tyr251, and Co-IP in P. falciparum","pmids":["19165323"],"confidence":"Medium","gaps":["Full atomic interface not resolved in this study","Single-residue analysis in one species"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"claim":"A genetic rescue with the released AMA1 cytoplasmic tail proposed that ROM4 cleavage of AMA1 triggers the switch from invasive to replicative mode — a model later revised.","evidence":"Conditional overexpression of dominant-negative TgROM4 rescued by AMA1 cytoplasmic-tail constructs, with replication assays (a 2025 erratum was subsequently issued)","pmids":["21205639","41379978"],"confidence":"High","gaps":["Replication-switch interpretation contradicted by later invasion-specific data (#15)","Downstream signaling of the released tail undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"claim":"The AMA1 ectodomain crystal structure defined a central hydrophobic groove framed by Trp353/Trp354/Tyr230 and gated by a short DII loop, giving an atomic candidate for the RON2 binding site.","evidence":"2.0 Å X-ray crystal structure of full-length TgAMA1 ectodomain","pmids":["20304917"],"confidence":"High","gaps":["Ligand-bound conformation not yet captured","Function of the DII loop untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"claim":"Knockout of ROM4 showed rhomboid processing of AMA1 and other adhesins establishes the apical-posterior surface gradient needed for apical orientation, gliding, and MJ formation.","evidence":"Tetracycline-regulatable ROM4 conditional knockout with adhesin surface IFA, invasion, and motility assays in T. gondii","pmids":["20421941"],"confidence":"High","gaps":["Whether ROM4 is the sole AMA1 protease unresolved (later addressed by #22)","Coupling of surface gradient to junction formation mechanistically incomplete"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"claim":"Defining the AMA1-binding region of RON2 (D3/D4 segments) and showing D3 peptide blocks invasion without preventing rhoptry injection established RON2 as the molecular bridge tethering AMA1 to the host-cell-anchored MJ, downstream of effector delivery.","evidence":"Recombinant RON2 fragment pull-downs, MJ localization, invasion inhibition with D3-GST, and evacuole assays in T. gondii; complementary interaction and topology mapping plus invasion inhibition in T. gondii and P. falciparum","pmids":["21347354","21347343"],"confidence":"High","gaps":["Atomic-resolution interface not yet solved in these studies","How the bridge withstands invasion forces unaddressed"],"attribution":[{"species":"Toxoplasma gondii","strain":""},{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"claim":"AMA1 propeptide aliphatic residues were shown to be required for trafficking of AMA1 to the micronemes, defining the sorting determinant.","evidence":"Propeptide mutagenesis and GFP reporter trafficking assays in T. gondii","pmids":["21438967"],"confidence":"Medium","gaps":["Receptor recognizing the propeptide signal not identified","AMA1 finding embedded in a broader MIC propeptide study"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"claim":"The AMA1–RON2 peptide co-crystal structure revealed a stepwise assembly producing an extensive buried interface, explaining how the junction resists the mechanical forces of penetration.","evidence":"1.95 Å X-ray structure of TgAMA1 bound to a TgRON2 peptide","pmids":["21778402"],"confidence":"High","gaps":["Dynamics of assembly in the membrane not captured","Contribution of the DII loop to selectivity not yet dissected"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"claim":"Genetic dissection showed AMA1 is dispensable for RON4 ring formation and functional junction assembly but enhances apposition and internalization frequency, and that RON4 can act without AMA1 in Plasmodium sporozoites — decoupling junction assembly from AMA1.","evidence":"Conditional knockdown/knockout of AMA1 and RON4 with invasion assays and RON4 ring IFA in T. gondii and P. berghei","pmids":["22177563"],"confidence":"High","gaps":["What supports residual invasion without AMA1 not yet identified (later attributed to paralogs, #18)","Mechanism of the apposition enhancement unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2012,"claim":"Cleavage-resistant AMA1 knock-in alleles revealed that intramembrane proteolysis of AMA1 promotes invasion specifically — refuting the earlier replication-switch model.","evidence":"TM-domain mutagenesis, heterologous cleavage assays, and knock-in complementation of a conditional knockout with growth/invasion readouts in T. gondii","pmids":["22523242"],"confidence":"High","gaps":["Precise step of invasion enabled by cleavage not fully defined","Reconciliation with the released-tail signaling proposal incomplete"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2013,"claim":"Deleting AMA1 across three zoite types in two species showed AMA1-null parasites are impaired in attachment but penetrate junctions normally, redefining AMA1 as a dispensable adhesin rather than an essential invasin.","evidence":"Genetic AMA1 deletion in Plasmodium sporozoites/merozoites and T. gondii RH tachyzoites, with assays separating attachment from penetration","pmids":["24108241"],"confidence":"High","gaps":["Compensating molecules not identified in this study","Quantitative contribution of AMA1 to natural infection unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":"RH"},{"species":"Plasmodium falciparum","strain":""}]},{"year":2013,"claim":"Discovery of exclusively self-pairing sporozoite paralogs sporoAMA1/sporoRON2, with allosteric conformational change on binding and stage-specific peptide inhibition, revealed stage-specialized AMA1–RON2 modules governing invasion in a life-cycle-specific manner.","evidence":"IFA localization, interaction-specificity binding assays, crystallography of the sporoAMA1–sporoRON2 complex, and stage-specific invasion inhibition in T. gondii","pmids":["23940612"],"confidence":"High","gaps":["Regulation of paralog expression across stages unresolved","In vivo requirement of the sporozoite module untested here"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"claim":"AMA1 gene disruption triggering compensatory AMA/RON paralog upregulation explained residual invasion in AMA1-null parasites and demonstrated molecular plasticity in MJ architecture while confirming AMA1–RON2 maintains junction integrity.","evidence":"Reverse genetics, conditional complementation, IFA, Western blot for paralog upregulation, and invasion assays in T. gondii","pmids":["24934579"],"confidence":"High","gaps":["Trigger controlling paralog upregulation unknown","Whether paralogs form structurally identical junctions unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"claim":"Combining aldolase-binding mutants with an aldolase knockout established that the AMA1 cytoplasmic tail–aldolase interaction is dispensable for invasion — a negative result overturning the adhesin–motor linkage model for AMA1.","evidence":"In vitro tail–aldolase binding, mutagenesis, ALD conditional knockout, and gliding/invasion assays in T. gondii","pmids":["24550496"],"confidence":"High","gaps":["The actual force-transducing partner of the AMA1 tail unidentified","Whether the tail engages the motor at all is unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"claim":"Structural and biophysical analysis showed the DII loop acts as a gatekeeper controlling groove access and RON2-ligand selectivity, since its deletion permits high-affinity binding of a normally weak Eimeria RON2 peptide.","evidence":"ITC with a RON2 peptide panel, DII-loop deletion mutagenesis, and crystallography of the TgAMA1ΔDIIloop–EtRON2 complex","pmids":["25955165"],"confidence":"High","gaps":["Physiological signal that repositions the DII loop unknown","Selectivity role during natural cross-species interactions untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"claim":"Double-protease knockouts established that both ROM4 and ROM5 cleave AMA1, with ROM5 accounting for residual cleavage in the absence of ROM4, refining the identity of the responsible rhomboids.","evidence":"Cre and CRISPR-Cas9 knockouts of ROM4 and ROM5 with Western blot of AMA1 cleavage products and invasion/motility assays in T. gondii","pmids":["25846828"],"confidence":"High","gaps":["Relative contribution of each rhomboid during live invasion unresolved","Regulation of cleavage timing not defined here"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2015,"claim":"Identifying AMA1 palmitoylation and showing its blockade enhances release of AMA1 and other invasion proteins from micronemes established a lipid-modification switch controlling AMA1 retention/secretion.","evidence":"Acyl-RAC chemical proteomics, palmitoylation-site mutagenesis, and microneme secretion assays in T. gondii","pmids":["26468752"],"confidence":"Medium","gaps":["Palmitoyltransferase acting on AMA1 not identified","Coupling of palmitoylation cycle to secretion signal unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2016,"claim":"Showing that RON2 D3 binding protects AMA1 from rhomboid cleavage and drives dephosphorylation of tail Ser527, with a phosphomimetic S527D allele impairing invasion, established outside-in signaling through the AMA1–RON2 junction that couples ligand engagement to cleavage protection and tail phosphoregulation of invasion.","evidence":"Rhomboid cleavage assays ± D3 peptide, MS phosphorylation analysis, and allele-replacement genetics (phosphomimetic/phospho-null) with invasion assays in T. gondii","pmids":["27624124"],"confidence":"High","gaps":["Kinase/phosphatase acting on Ser527 not identified","Downstream effectors of the dephosphorylation signal undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2023,"claim":"Mapping stage-specific MJ composition showed bradyzoites invade using paralogs AMA2/AMA4 (AMA4 driving early cyst burden) rather than AMA1, and that AMA1–RON2 immunization protects against acute and chronic infection, extending AMA1 biology to chronic-stage invasion and vaccine potential.","evidence":"Bradyzoite IFA, AMA4 knockout with cyst-burden quantification, and mouse vaccination/challenge with AMA1-RON2 in T. gondii","pmids":["36693095"],"confidence":"High","gaps":["Regulatory basis of stage-specific paralog usage unknown","Structural interface of bradyzoite AMA paralogs unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The identity of the cytoplasmic effectors that transduce AMA1 tail dephosphorylation and cleaved-tail signaling into invasion outcomes, and the regulatory logic governing stage-specific AMA/RON paralog deployment, remain open.","evidence":"No timeline discovery identifies the kinase/phosphatase or downstream signaling partners of the AMA1 tail, nor the transcriptional/post-transcriptional control of paralog switching","pmids":[],"confidence":"Low","gaps":["Ser527 kinase and phosphatase unidentified","Force-transducing partner of the AMA1 cytoplasmic tail unknown","Mechanism selecting AMA1 vs. paralogs across life-cycle stages undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Moving junction complex (AMA1 with RON2/RON4/RON5/RON8)","TgAMA1–TgRON2 core adhesion pair","sporoAMA1–sporoRON2 sporozoite-stage complex","AMA2/AMA4-based bradyzoite moving junction"],"partners":["RON2 (RON2 C-TERMINAL D3/D4 REGION; DIRECT LIGAND IN HYDROPHOBIC GROOVE)","RON4","RON5","RON8","ROM4 (RHOMBOID PROTEASE; CLEAVES AMA1 TM DOMAIN)","ROM5 (RHOMBOID PROTEASE; RESIDUAL AMA1 CLEAVAGE)","FRUCTOSE-1,6-BISPHOSPHATE ALDOLASE (ALD; BINDS CYTOPLASMIC TAIL IN VITRO BUT DISPENSABLE FOR INVASION)"],"other_free_text":["Type I transmembrane protein with an ectodomain (domains I/II/III), a central hydrophobic RON2-binding groove framed by Trp353/Trp354/Tyr230, and a mobile DII loop acting as a selectivity gatekeeper.","Cytoplasmic tail carries a regulatory phosphosite (Ser527); RON2 binding drives its dephosphorylation and a phosphomimetic S527D allele impairs invasion (outside-in signaling).","Secretion from micronemes is calcium-regulated and further tuned by palmitoylation; propeptide aliphatic residues direct microneme trafficking.","Functionally a critical but dispensable adhesin: null parasites retain junction-mediated penetration, and loss is buffered by compensatory upregulation of AMA/RON paralogs.","Stage-specific paralog usage: tachyzoites use AMA1, sporozoites use sporoAMA1/sporoRON2, bradyzoites use AMA2/AMA4.","AMA1–RON2 immunization protects against acute and chronic Toxoplasma infection.","The 2010 replication-switch model for cleaved AMA1 tail (#8) was revised by later invasion-specific genetic evidence (#15); the #8 paper also carries a 2025 erratum."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"16244709","id":"PMC_16244709","title":"Identification of the moving junction complex of Toxoplasma gondii: a collaboration between distinct secretory organelles.","date":"2005","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/16244709","citation_count":327,"is_preprint":false},{"pmid":"21347343","id":"PMC_21347343","title":"The RON2-AMA1 interaction is a critical step in moving junction-dependent invasion by apicomplexan parasites.","date":"2011","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/21347343","citation_count":268,"is_preprint":false},{"pmid":"19247437","id":"PMC_19247437","title":"Export of a Toxoplasma gondii rhoptry neck protein complex at the host cell membrane to form the moving junction during invasion.","date":"2009","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/19247437","citation_count":238,"is_preprint":false},{"pmid":"21535344","id":"PMC_21535344","title":"The moving junction of apicomplexan parasites: a key structure for invasion.","date":"2011","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/21535344","citation_count":227,"is_preprint":false},{"pmid":"16000372","id":"PMC_16000372","title":"Conditional expression of Toxoplasma gondii apical membrane antigen-1 (TgAMA1) demonstrates that TgAMA1 plays a critical role in host cell invasion.","date":"2005","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/16000372","citation_count":196,"is_preprint":false},{"pmid":"21778402","id":"PMC_21778402","title":"Host cell invasion by apicomplexan parasites: insights from the co-structure of AMA1 with a RON2 peptide.","date":"2011","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/21778402","citation_count":155,"is_preprint":false},{"pmid":"22347997","id":"PMC_22347997","title":"Transcriptomic analysis of toxoplasma development reveals many novel functions and structures specific to sporozoites and oocysts.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22347997","citation_count":140,"is_preprint":false},{"pmid":"19165323","id":"PMC_19165323","title":"An inhibitory antibody blocks interactions between components of the malarial invasion machinery.","date":"2009","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/19165323","citation_count":139,"is_preprint":false},{"pmid":"11083833","id":"PMC_11083833","title":"Toxoplasma gondii homologue of plasmodium apical membrane antigen 1 is involved in invasion of host cells.","date":"2000","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/11083833","citation_count":134,"is_preprint":false},{"pmid":"24934579","id":"PMC_24934579","title":"Plasticity and redundancy among AMA-RON pairs ensure host cell entry of Toxoplasma parasites.","date":"2014","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/24934579","citation_count":128,"is_preprint":false},{"pmid":"16835460","id":"PMC_16835460","title":"Plasmodium falciparum AMA1 binds a rhoptry neck protein homologous to TgRON4, a component of the moving junction in Toxoplasma gondii.","date":"2006","source":"Eukaryotic cell","url":"https://pubmed.ncbi.nlm.nih.gov/16835460","citation_count":127,"is_preprint":false},{"pmid":"24108241","id":"PMC_24108241","title":"Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion.","date":"2013","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/24108241","citation_count":113,"is_preprint":false},{"pmid":"21347354","id":"PMC_21347354","title":"The C-terminus of Toxoplasma RON2 provides the crucial link between AMA1 and the host-associated invasion complex.","date":"2011","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/21347354","citation_count":105,"is_preprint":false},{"pmid":"20421941","id":"PMC_20421941","title":"Rhomboid 4 (ROM4) affects the processing of surface adhesins and facilitates host cell invasion by Toxoplasma gondii.","date":"2010","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/20421941","citation_count":101,"is_preprint":false},{"pmid":"22177563","id":"PMC_22177563","title":"Independent roles of apical membrane antigen 1 and rhoptry neck proteins during host cell invasion by apicomplexa.","date":"2011","source":"Cell host & microbe","url":"https://pubmed.ncbi.nlm.nih.gov/22177563","citation_count":100,"is_preprint":false},{"pmid":"24550496","id":"PMC_24550496","title":"Toxoplasma aldolase is required for metabolism but dispensable for host-cell invasion.","date":"2014","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/24550496","citation_count":100,"is_preprint":false},{"pmid":"21347348","id":"PMC_21347348","title":"Genetic mapping identifies novel highly protective antigens for an apicomplexan parasite.","date":"2011","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/21347348","citation_count":96,"is_preprint":false},{"pmid":"11087913","id":"PMC_11087913","title":"The Toxoplasma homolog of Plasmodium apical membrane antigen-1 (AMA-1) is a microneme protein secreted in response to elevated intracellular calcium levels.","date":"2000","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/11087913","citation_count":92,"is_preprint":false},{"pmid":"24632839","id":"PMC_24632839","title":"The toxoplasma Acto-MyoA motor complex is important but not essential for gliding motility and host cell invasion.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24632839","citation_count":91,"is_preprint":false},{"pmid":"21205639","id":"PMC_21205639","title":"Intramembrane cleavage of AMA1 triggers Toxoplasma to switch from an invasive to a replicative mode.","date":"2010","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/21205639","citation_count":82,"is_preprint":false},{"pmid":"16102004","id":"PMC_16102004","title":"Distinct mechanisms govern proteolytic shedding of a key invasion protein in apicomplexan pathogens.","date":"2005","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/16102004","citation_count":78,"is_preprint":false},{"pmid":"21659001","id":"PMC_21659001","title":"Focus on the ringleader: the role of AMA1 in apicomplexan invasion and replication.","date":"2011","source":"Trends in parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/21659001","citation_count":71,"is_preprint":false},{"pmid":"26468752","id":"PMC_26468752","title":"Global Analysis of Palmitoylated Proteins in Toxoplasma gondii.","date":"2015","source":"Cell host & microbe","url":"https://pubmed.ncbi.nlm.nih.gov/26468752","citation_count":66,"is_preprint":false},{"pmid":"20545864","id":"PMC_20545864","title":"Toxoplasma gondii transmembrane microneme proteins and their modular design.","date":"2010","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/20545864","citation_count":60,"is_preprint":false},{"pmid":"17379212","id":"PMC_17379212","title":"Toxoplasma gondii: DNA vaccination with genes encoding antigens MIC2, M2AP, AMA1 and BAG1 and evaluation of their immunogenic potential.","date":"2007","source":"Experimental parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/17379212","citation_count":58,"is_preprint":false},{"pmid":"17156863","id":"PMC_17156863","title":"Apical membrane antigen 1 is a cross-reactive antigen between Neospora caninum and Toxoplasma gondii, and the anti-NcAMA1 antibody inhibits host cell invasion by both parasites.","date":"2006","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/17156863","citation_count":58,"is_preprint":false},{"pmid":"21423671","id":"PMC_21423671","title":"The moving junction protein RON8 facilitates firm attachment and host cell invasion in Toxoplasma gondii.","date":"2011","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/21423671","citation_count":52,"is_preprint":false},{"pmid":"24651769","id":"PMC_24651769","title":"RON5 is critical for organization and function of the Toxoplasma moving junction complex.","date":"2014","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/24651769","citation_count":47,"is_preprint":false},{"pmid":"23940612","id":"PMC_23940612","title":"Toxoplasma gondii sporozoites invade host cells using two novel paralogues of RON2 and AMA1.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23940612","citation_count":46,"is_preprint":false},{"pmid":"20304917","id":"PMC_20304917","title":"Structural characterization of apical membrane antigen 1 (AMA1) from Toxoplasma gondii.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20304917","citation_count":45,"is_preprint":false},{"pmid":"16333076","id":"PMC_16333076","title":"Use of recombinant antigens for early postnatal diagnosis of congenital toxoplasmosis.","date":"2005","source":"Journal of clinical microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/16333076","citation_count":43,"is_preprint":false},{"pmid":"18310358","id":"PMC_18310358","title":"Microneme rhomboid protease TgROM1 is required for efficient intracellular growth of Toxoplasma gondii.","date":"2008","source":"Eukaryotic cell","url":"https://pubmed.ncbi.nlm.nih.gov/18310358","citation_count":41,"is_preprint":false},{"pmid":"25846828","id":"PMC_25846828","title":"Distinct contribution of Toxoplasma gondii rhomboid proteases 4 and 5 to micronemal protein protease 1 activity during invasion.","date":"2015","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/25846828","citation_count":39,"is_preprint":false},{"pmid":"30181047","id":"PMC_30181047","title":"Characterization of a multi-epitope peptide with selective MHC-binding capabilities encapsulated in PLGA nanoparticles as a novel vaccine candidate against Toxoplasma gondii infection.","date":"2018","source":"Vaccine","url":"https://pubmed.ncbi.nlm.nih.gov/30181047","citation_count":38,"is_preprint":false},{"pmid":"18710865","id":"PMC_18710865","title":"Identification and characterization of the Plasmodium yoelii PyP140/RON4 protein, an orthologue of Toxoplasma gondii RON4, whose cysteine-rich domain does not protect against lethal parasite challenge infection.","date":"2008","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/18710865","citation_count":32,"is_preprint":false},{"pmid":"22523242","id":"PMC_22523242","title":"Intramembrane proteolysis of Toxoplasma apical membrane antigen 1 facilitates host-cell invasion but is dispensable for replication.","date":"2012","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/22523242","citation_count":31,"is_preprint":false},{"pmid":"21438967","id":"PMC_21438967","title":"Forward targeting of Toxoplasma gondii proproteins to the micronemes involves conserved aliphatic amino acids.","date":"2011","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/21438967","citation_count":29,"is_preprint":false},{"pmid":"25582167","id":"PMC_25582167","title":"Protective immunity induced by peptides of AMA1, RON2 and RON4 containing T-and B-cell epitopes via an intranasal route against toxoplasmosis in mice.","date":"2015","source":"Parasites & vectors","url":"https://pubmed.ncbi.nlm.nih.gov/25582167","citation_count":28,"is_preprint":false},{"pmid":"25157917","id":"PMC_25157917","title":"Insights and controversies into the role of the key apicomplexan invasion ligand, Apical Membrane Antigen 1.","date":"2014","source":"International journal for parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/25157917","citation_count":28,"is_preprint":false},{"pmid":"31170254","id":"PMC_31170254","title":"The first study on the usefulness of recombinant tetravalent chimeric proteins containing fragments of SAG2, GRA1, ROP1 and AMA1 antigens in the detection of specific anti-Toxoplasma gondii antibodies in mouse and human sera.","date":"2019","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/31170254","citation_count":27,"is_preprint":false},{"pmid":"28077075","id":"PMC_28077075","title":"Protection via a ROM4 DNA vaccine and peptide against Toxoplasma gondii in BALB/c mice.","date":"2017","source":"BMC infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/28077075","citation_count":25,"is_preprint":false},{"pmid":"36693095","id":"PMC_36693095","title":"Invasion of Toxoplasma gondii bradyzoites: Molecular dissection of the moving junction proteins and effective vaccination targets.","date":"2023","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/36693095","citation_count":24,"is_preprint":false},{"pmid":"25847964","id":"PMC_25847964","title":"AMA1-deficient Toxoplasma gondii parasites transiently colonize mice and trigger an innate immune response that leads to long-lasting protective immunity.","date":"2015","source":"Infection and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/25847964","citation_count":21,"is_preprint":false},{"pmid":"22537971","id":"PMC_22537971","title":"Protective effect of a prime-boost strategy with plasmid DNA followed by recombinant adenovirus expressing TgAMA1 as vaccines against Toxoplasma gondii infection in mice.","date":"2012","source":"Parasitology international","url":"https://pubmed.ncbi.nlm.nih.gov/22537971","citation_count":21,"is_preprint":false},{"pmid":"27624124","id":"PMC_27624124","title":"Not a Simple Tether: Binding of Toxoplasma gondii AMA1 to RON2 during Invasion Protects AMA1 from Rhomboid-Mediated Cleavage and Leads to Dephosphorylation of Its Cytosolic Tail.","date":"2016","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/27624124","citation_count":20,"is_preprint":false},{"pmid":"31948063","id":"PMC_31948063","title":"Toxoplasma gondii Recombinant antigen AMA1: Diagnostic Utility of Protein Fragments for the Detection of IgG and IgM Antibodies.","date":"2020","source":"Pathogens (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/31948063","citation_count":18,"is_preprint":false},{"pmid":"25955165","id":"PMC_25955165","title":"An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1) Governs Ligand Binding Selectivity.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25955165","citation_count":16,"is_preprint":false},{"pmid":"29263399","id":"PMC_29263399","title":"RON4L1 is a new member of the moving junction complex in Toxoplasma gondii.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/29263399","citation_count":16,"is_preprint":false},{"pmid":"32097746","id":"PMC_32097746","title":"Virus-like particle vaccine displaying Toxoplasma gondii apical membrane antigen 1 induces protection against T. gondii ME49 infection in mice.","date":"2020","source":"Microbial pathogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/32097746","citation_count":16,"is_preprint":false},{"pmid":"23714365","id":"PMC_23714365","title":"Comparative characterization of microRNA profiles of different genotypes of Toxoplasma gondii.","date":"2013","source":"Parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/23714365","citation_count":13,"is_preprint":false},{"pmid":"27445648","id":"PMC_27445648","title":"Multilevel Precision-Based Rational Design of Chemical Inhibitors Targeting the Hydrophobic Cleft of Toxoplasma gondii Apical Membrane Antigen 1 (AMA1).","date":"2016","source":"Genomics & informatics","url":"https://pubmed.ncbi.nlm.nih.gov/27445648","citation_count":11,"is_preprint":false},{"pmid":"31847285","id":"PMC_31847285","title":"Toxoplasma gondii Tetravalent Chimeric Proteins as Novel Antigens for Detection of Specific Immunoglobulin G in Sera of Small Ruminants.","date":"2019","source":"Animals : an open access journal from MDPI","url":"https://pubmed.ncbi.nlm.nih.gov/31847285","citation_count":11,"is_preprint":false},{"pmid":"38673969","id":"PMC_38673969","title":"The Development of Toxoplasma gondii Recombinant Trivalent Chimeric Proteins as an Alternative to Toxoplasma Lysate Antigen (TLA) in Enzyme-Linked Immunosorbent Assay (ELISA) for the Detection of Immunoglobulin G (IgG) in Small Ruminants.","date":"2024","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/38673969","citation_count":8,"is_preprint":false},{"pmid":"36359332","id":"PMC_36359332","title":"Recombinant AMA1 Virus-like Particle Antigen for Serodiagnosis of Toxoplasma gondii Infection.","date":"2022","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/36359332","citation_count":7,"is_preprint":false},{"pmid":"33276579","id":"PMC_33276579","title":"The Immunogenic and Immunoprotective Activities of Recombinant Chimeric T. gondii Proteins Containing AMA1 Antigen Fragments.","date":"2020","source":"Vaccines","url":"https://pubmed.ncbi.nlm.nih.gov/33276579","citation_count":6,"is_preprint":false},{"pmid":"28662729","id":"PMC_28662729","title":"The moving junction protein RON4, although not critical, facilitates host cell invasion and stabilizes MJ members.","date":"2017","source":"Parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/28662729","citation_count":6,"is_preprint":false},{"pmid":"37519774","id":"PMC_37519774","title":"Screening of apical membrane antigen-1 (AMA1), dense granule protein-7 (GRA7) and rhoptry protein-16 (ROP16) antigens for a potential vaccine candidate against Toxoplasma gondii for chickens.","date":"2023","source":"Vaccine: X","url":"https://pubmed.ncbi.nlm.nih.gov/37519774","citation_count":5,"is_preprint":false},{"pmid":"37924072","id":"PMC_37924072","title":"Establishment and application of an iELISA detection method for measuring apical membrane antigen 1 (AMA1) antibodies of Toxoplasma gondii in cats.","date":"2023","source":"BMC veterinary research","url":"https://pubmed.ncbi.nlm.nih.gov/37924072","citation_count":5,"is_preprint":false},{"pmid":"30069207","id":"PMC_30069207","title":"Construction of an Adenovirus Vaccine Expressing the Cross-reactive Antigen AMA1 for Neospora caninum and Toxoplasma gondii and Its Immune Response in an Animal Model.","date":"2018","source":"Iranian journal of parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/30069207","citation_count":5,"is_preprint":false},{"pmid":"36403800","id":"PMC_36403800","title":"Immunological evaluation of a novel multi-antigenic DNA vaccine encoding SAG1, SAG3, MIC4, GRA5, GRA7, AMA1and BAG1 against Toxoplasma gondii in BALB/c mice.","date":"2022","source":"Experimental parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/36403800","citation_count":5,"is_preprint":false},{"pmid":"41311041","id":"PMC_41311041","title":"Vaccinia virus expressing MIC8 and AMA1 provides protection against Toxoplasma gondii ME49 infection.","date":"2025","source":"Parasites, hosts and diseases","url":"https://pubmed.ncbi.nlm.nih.gov/41311041","citation_count":3,"is_preprint":false},{"pmid":"40886931","id":"PMC_40886931","title":"Recombinant vaccinia virus expressing MIC8, AMA1, or RON4 induce protection against Toxoplasma gondii ME49 strain infection.","date":"2025","source":"Acta tropica","url":"https://pubmed.ncbi.nlm.nih.gov/40886931","citation_count":3,"is_preprint":false},{"pmid":"40255910","id":"PMC_40255910","title":"In Silico-Based Investigation of the Immunogenicity and Biochemical Attributes of Toxoplasma gondii Apical Membrane Antigen 1 (TgAMA1).","date":"2025","source":"Journal of parasitology research","url":"https://pubmed.ncbi.nlm.nih.gov/40255910","citation_count":3,"is_preprint":false},{"pmid":"40872947","id":"PMC_40872947","title":"Efficacy of Heterologous Vaccination Using Virus-Like Particles and Vaccinia Virus Containing MIC8 and AMA1 Proteins of Toxoplasma gondii.","date":"2025","source":"Vaccines","url":"https://pubmed.ncbi.nlm.nih.gov/40872947","citation_count":2,"is_preprint":false},{"pmid":"21718637","id":"PMC_21718637","title":"[TgROM4 and TgAMA1: a checkpoint in parasite replication].","date":"2011","source":"Medecine sciences : M/S","url":"https://pubmed.ncbi.nlm.nih.gov/21718637","citation_count":2,"is_preprint":false},{"pmid":"42142636","id":"PMC_42142636","title":"Resveratrol modulates inflammatory gene expression in Toxoplasma gondii-infected microglia and shows structurally plausible interactions with parasite virulence proteins.","date":"2026","source":"Microbial pathogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/42142636","citation_count":0,"is_preprint":false},{"pmid":"41379978","id":"PMC_41379978","title":"Erratum for the Report \"Intramembrane cleavage of AMA1 triggers Toxoplasma to switch from an invasive to a replicative mode\" by J. M. Santos et al.","date":"2025","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/41379978","citation_count":0,"is_preprint":false},{"pmid":"40102442","id":"PMC_40102442","title":"Functionality of Toxoplasma gondii antibodies in a population of Beninese pregnant women exposed to malaria.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/40102442","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":33959,"output_tokens":7486,"usd":0.107083,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":15360,"output_tokens":9284,"usd":0.15445,"stage2_stop_reason":"end_turn"},"total_usd":0.0,"stage1_batch_id":"msgbatch_01XFXJD6iZecXyWn9uU5Qom9","stage2_batch_id":"msgbatch_013GToKgs4AKSCRE4yvueviH","note":"batch pricing = 50% of standard","skipped":true},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"TgAMA1 is a type I transmembrane protein that localizes to micronemes in intracellular tachyzoites; upon release of mature tachyzoites, it redistributes predominantly to the apical end of the parasite surface. A ~54 kDa N-terminal cleavage product is constitutively shed into the medium by extracellular parasites. Antiserum against recombinant TgAMA1 blocked invasion by ~40%, and viable TgAMA1 knockout could not be produced, indicating an essential role in invasion.\",\n      \"method\": \"Immunofluorescence assay, immunoelectron microscopy, Triton X-114 phase partitioning, iodonaphthalene azide labeling, knockout attempt, invasion inhibition assay with antiserum\",\n      \"journal\": \"Infection and immunity\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (IFA, IEM, biochemical fractionation, functional knockout attempt, invasion inhibition), replicated by multiple subsequent studies\",\n      \"pmids\": [\"11083833\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"TgAMA1 secretion from micronemes is dramatically enhanced in response to treatments that elevate intracellular calcium levels, consistent with calcium-regulated microneme secretion.\",\n      \"method\": \"Calcium ionophore/ethanol stimulation assay with immunofluorescence and Western blot monitoring of TgAMA1 release\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct stimulation experiment with biochemical readout, single lab but consistent with broader MIC secretion biology\",\n      \"pmids\": [\"11087913\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Conditional depletion of TgAMA1 severely impairs host cell invasion without affecting microneme secretion or initial host cell attachment, but inhibits rhoptry secretion, suggesting TgAMA1 acts after initial attachment to regulate rhoptry discharge.\",\n      \"method\": \"Regulatable promoter conditional knockout, invasion assay, microneme secretion assay, rhoptry secretion assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional genetic knockout with multiple distinct functional readouts (invasion, microneme secretion, rhoptry secretion), landmark study widely replicated\",\n      \"pmids\": [\"16000372\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"TgAMA1 associates with a trio of proteins at the moving junction (MJ); at least one of these partners derives from the rhoptry neck (RON proteins), revealing an unexpected collaboration between microneme-derived AMA1 and rhoptry neck proteins at the MJ.\",\n      \"method\": \"Co-immunoprecipitation, immunoelectron microscopy localizing complex members to the MJ\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP identifying complex plus IEM localization to MJ, independently confirmed by multiple subsequent studies\",\n      \"pmids\": [\"16244709\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"TgAMA1 is shed from the surface of extracellular tachyzoites via intramembrane cleavage within the luminal half of its transmembrane domain by a rhomboid-like protease, unlike PfAMA1 which is shed by juxtamembrane cleavage. Complete TgAMA1 shedding does not accompany invasion, as intact protein is detected on newly invaded tachyzoites.\",\n      \"method\": \"Pulse-chase metabolic labeling, inhibitor studies, comparison with Drosophila rhomboid-1 cleavage assay, Western blot of surface protein during invasion\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro rhomboid cleavage assay plus pulse-chase, single study\",\n      \"pmids\": [\"16102004\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"PfAMA1 co-immunoprecipitates with the Plasmodium falciparum homologue of TgRON4, a rhoptry neck protein, demonstrating that the AMA1–RON4 association is conserved between Toxoplasma and Plasmodium.\",\n      \"method\": \"Co-immunoprecipitation of native parasite proteins\",\n      \"journal\": \"Eukaryotic cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP in P. falciparum supporting conservation, single lab\",\n      \"pmids\": [\"16835460\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The rhoptry neck proteins RON2, RON4, RON5, and RON8 form a complex that is exported to the host cell membrane during invasion, where RON4/5/8 associate with the cytoplasmic face, while AMA1 is inserted into the parasite membrane. RON2 and AMA1 can interact in the absence of other MJ members, and all MJ proteins undergo proteolytic maturation during trafficking to their organelles.\",\n      \"method\": \"Metabolic labeling, immunoprecipitation, differential permeabilization with digitonin/saponin, antibody loading into host cell, immunofluorescence\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal biochemical methods establishing topology and pairwise interactions, replicated across labs\",\n      \"pmids\": [\"19247437\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"An invasion-inhibitory anti-PfAMA1 monoclonal antibody (mAb 4G2) cannot bind PfAMA1 when PfAMA1 is in complex with its RON partners; a single conserved residue Tyr251 in PfAMA1, located in the hydrophobic groove, is required for complex formation, suggesting mAb 4G2 inhibits invasion by blocking PfAMA1–RON interaction.\",\n      \"method\": \"Antibody competition assay, site-directed mutagenesis of PfAMA1 Tyr251, co-immunoprecipitation\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis plus binding assay, single study in P. falciparum\",\n      \"pmids\": [\"19165323\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Conditional overexpression of a catalytically inactive TgROM4 (rhomboid 4) caused a profound block in parasite replication that was completely rescued by expression of the cleaved cytoplasmic tail of TgAMA1 or PfAMA1, revealing that intramembrane cleavage of AMA1 by ROM4 and subsequent release of its cytoplasmic tail triggers the parasite's switch from an invasive to a replicative mode.\",\n      \"method\": \"Conditional overexpression of dominant-negative TgROM4, rescue with AMA1 cytoplasmic tail expression constructs, replication assay\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — genetic rescue experiment with defined molecular construct, published in Science; however a 2025 erratum (PMID 41379978) was issued for this paper, slightly reducing confidence\",\n      \"pmids\": [\"21205639\", \"41379978\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The 2.0 Å X-ray crystal structure of full-length TgAMA1 ectodomain (domains I, II, III) reveals a central hydrophobic groove framed by conserved residues Trp353, Trp354, and Tyr230 from the DII loop, proposed as the RON2 binding site. The DII loop is 14 residues shorter than in Plasmodium AMA1 homologs and restricts access to the groove.\",\n      \"method\": \"X-ray crystallography at 2.0 Å resolution\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure with >97.5% of ectodomain modeled, landmark structural paper\",\n      \"pmids\": [\"20304917\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"TgROM4 processes surface adhesins MIC2, AMA1, and MIC3; its suppression decreases MIC2 release into the supernatant, increases surface expression of adhesins, disrupts the normal apical-posterior gradient needed for efficient gliding motility, and severely impairs invasion. Parasites lacking TgROM4 bind host cells better but fail to apically orient and cannot generate a moving junction.\",\n      \"method\": \"Conditional knockout (tetracycline-regulatable), surface adhesin immunofluorescence, invasion assay, motility assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional genetic KO with multiple mechanistic readouts across two papers\",\n      \"pmids\": [\"20421941\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The C-terminus of TgRON2 contains two short segments (D3 and D4) flanking a hydrophobic stretch that independently bind the ectodomain of TgAMA1. Pre-incubation with D3-GST fusion dramatically reduces invasion but does not prevent rhoptry bulb protein injection, demonstrating that TgRON2's C-terminal region forms the bridge between TgAMA1 and the host cell-associated MJ complex but is not required for rhoptry effector delivery.\",\n      \"method\": \"Immunofluorescence localization of TgRON2 to MJ, pull-down assays with recombinant RON2 fragments, invasion inhibition assay with D3-GST, evacuole assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (pull-down, localization, functional inhibition with defined peptide, evacuole assay), single lab\",\n      \"pmids\": [\"21347354\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"RON2 is inserted as an integral membrane protein in the host cell, and the region of RON2 that binds AMA1 was defined using multiple interaction assays. Recombinant RON2 protein inhibits invasion of both T. gondii and P. falciparum, demonstrating that the RON2–AMA1 interaction is critical for host cell entry by apicomplexan parasites.\",\n      \"method\": \"Multiple interaction assays with native and recombinant proteins (pull-down, ELISA-based binding), invasion inhibition with recombinant proteins, differential permeabilization to show RON2 membrane topology\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal binding assays plus functional invasion inhibition in two parasite species\",\n      \"pmids\": [\"21347343\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}, {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The 1.95 Å crystal structure of TgAMA1 complexed with a TgRON2 peptide reveals a stepwise assembly mechanism producing an extensive buried surface area, providing structural explanation for how the MJ complex resists mechanical forces during invasion.\",\n      \"method\": \"X-ray crystallography at 1.95 Å resolution of TgAMA1–RON2 peptide complex\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution co-crystal structure with mechanistic interpretation validated by the interaction biology\",\n      \"pmids\": [\"21778402\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"In T. gondii tachyzoites, AMA1 is dispensable for normal RON4 ring formation and functional tight junction assembly but enhances tachyzoite apposition to the host cell and increases internalization frequency. In P. berghei sporozoites, only RON4 (not AMA1) is required for hepatocyte invasion, demonstrating RON4 can act independently of AMA1.\",\n      \"method\": \"Conditional genetic knockdown/knockout of AMA1 and RON4 in T. gondii and P. berghei, invasion assays, immunofluorescence for RON4 ring formation\",\n      \"journal\": \"Cell host & microbe\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockouts in two parasite species with functional readouts, published in Cell Host & Microbe\",\n      \"pmids\": [\"22177563\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Intramembrane proteolysis of TgAMA1 facilitates host cell invasion: parasites expressing an uncleavable TgAMA1(AG/FF+GG/FF) mutant show a growth defect due to impaired invasion, not replication. This refutes the model in which intramembrane cleavage of TgAMA1 regulates replication and instead demonstrates its role is invasion-specific.\",\n      \"method\": \"Heterologous cleavage assay to characterize transmembrane domain determinants, mutagenesis of TgAMA1 TM domain, complementation of conditional knockout with cleavage-resistant alleles (transgenic and knock-in), growth/invasion assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution plus mutagenesis plus knock-in genetic complementation with quantitative invasion/replication readouts\",\n      \"pmids\": [\"22523242\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Plasmodium merozoites and Toxoplasma tachyzoites lacking AMA1 are impaired in host cell attachment but retain normal host cell penetration through the moving junction, indicating AMA1 is a dispensable adhesin rather than an essential invasin for junction-mediated entry.\",\n      \"method\": \"Genetic deletion of AMA1 in Plasmodium sporozoites, merozoites, and T. gondii tachyzoites; invasion assays distinguishing attachment from penetration\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockouts in three zoite types across two apicomplexan species with dissection of attachment vs. penetration steps\",\n      \"pmids\": [\"24108241\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}, {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Toxoplasma sporozoites express paralogues sporoAMA1 and sporoRON2 that localize to the apical region; they interact specifically and exclusively with each other (not with generic AMA1/RON2). Structural studies show sporoRON2 domain 3 binding to sporoAMA1 domains I/II causes major conformational changes allosterically in domain III. Pre-treatment of sporozoites with sporoRON2 domain 3 peptide blocks sporozoite invasion without affecting tachyzoites, and vice versa for generic RON2 domain 3.\",\n      \"method\": \"Localization by immunofluorescence, pull-down/binding assays for interaction specificity, X-ray crystallography of sporoAMA1–sporoRON2 complex, invasion inhibition assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — crystallography plus binding assays plus functional invasion inhibition with stage-specific peptides\",\n      \"pmids\": [\"23940612\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Disruption of the AMA1 gene in T. gondii results in upregulation of AMA1 and RON2 homologues (paralogs) that cooperate to support residual invasion, demonstrating molecular plasticity in MJ architecture. AMA1 interacts with RON2 to maintain MJ structural integrity and is required for parasite internalization.\",\n      \"method\": \"Reverse genetics (AMA1 gene disruption), conditional complementation, immunofluorescence, invasion assays, Western blot for paralog upregulation\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reverse genetics with multiple functional readouts plus discovery of compensatory paralog upregulation\",\n      \"pmids\": [\"24934579\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"ALD (fructose-1,6-bisphosphate aldolase) binds the TgAMA1 cytoplasmic tail in vitro, but TgAMA1 cytoplasmic tail mutations that disrupt ALD binding in vitro show no correlation with host cell invasion in vivo. ALD knockout parasites show normal gliding and invasion in glucose-free medium, indicating ALD is not functionally essential for the adhesin-motor linkage and TgAMA1–aldolase interaction is dispensable for invasion.\",\n      \"method\": \"In vitro binding assay (cytoplasmic tail–aldolase), site-directed mutagenesis, ALD conditional depletion/knockout, invasion assay, gliding motility assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution plus mutagenesis plus genetic KO with multiple functional readouts; importantly establishes a NEGATIVE mechanistic finding (aldolase binding dispensable)\",\n      \"pmids\": [\"24550496\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"TgAMA1 is palmitoylated; blocking AMA1 palmitoylation enhances the release of AMA1 and other invasion-related proteins from apical secretory organelles (micronemes), suggesting palmitoylation regulates AMA1 retention/secretion from micronemes.\",\n      \"method\": \"Chemical proteomics (acyl-RAC capture for palmitoylated proteins), palmitoylation site mutagenesis, microneme secretion assay\",\n      \"journal\": \"Cell host & microbe\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — chemical proteomics plus mutagenesis/functional secretion assay, single lab\",\n      \"pmids\": [\"26468752\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The DII loop of TgAMA1 acts as a structural gatekeeper governing ligand binding selectivity in the hydrophobic groove: deletion of the mobile DII loop portion (TgAMA1ΔDIIloop) allows high-affinity binding of an Eimeria tenella RON2 peptide (EtRON2) that normally binds with only weak affinity, while the crystal structure of TgAMA1ΔDIIloop–EtRON2 reveals spatially distinct anchor points in the AMA1 groove.\",\n      \"method\": \"Isothermal titration calorimetry with RON2 peptide panel, engineering of DII loop deletion mutant, X-ray crystallography of complex\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — ITC binding measurements, mutagenesis, and crystal structure in one study\",\n      \"pmids\": [\"25955165\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"ROM4 and ROM5 both contribute to intramembrane cleavage (MPP1 activity) of AMA1 in T. gondii: ROM4 KO reduces but does not abolish AMA1 cleavage, while ROM5 accounts for residual AMA1 cleavage in the absence of ROM4 and can also cleave other AMA family members.\",\n      \"method\": \"Cre-recombinase and CRISPR-Cas9 knockouts of ROM4 and ROM5, Western blot for AMA1 cleavage products, invasion and motility assays\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — double genetic knockouts with molecular readout of cleavage products, two-gene epistasis\",\n      \"pmids\": [\"25846828\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Binding of TgRON2 D3 peptide to TgAMA1 protects TgAMA1 from rhomboid-mediated cleavage, thereby stabilizing the AMA1-host cell interaction at the moving junction. TgRON2 D3 binding also reduces phosphorylation of Ser527 on the TgAMA1 cytoplasmic tail; parasites expressing a phosphomimetic S527D TgAMA1 allele show an invasion defect, indicating outside-in signaling through the AMA1–RON2 interaction modulates invasion.\",\n      \"method\": \"Rhomboid cleavage assay with and without D3 peptide, phosphorylation analysis by mass spectrometry, transgenic complementation with phosphomimetic and phospho-null AMA1 alleles, invasion assays with hypercleavable AMA1 variants\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — cleavage protection assay, MS-based phosphorylation analysis, and allele-replacement genetics with invasion readout in one study\",\n      \"pmids\": [\"27624124\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Conserved aliphatic residues (valine at position +3 of proM2AP, leucine at position +1 of proMIC5) in MIC propeptides are required for microneme targeting; the AMA1 propeptide contains valine/leucine near its N-terminus and mutagenesis of these residues impairs trafficking of AMA1 to micronemes.\",\n      \"method\": \"N-terminal deletion and mutagenesis of propeptide domains, GFP reporter trafficking assays, cross-species propeptide swap experiments\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutagenesis with trafficking readout, single lab; AMA1 finding is part of broader MIC propeptide study\",\n      \"pmids\": [\"21438967\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"TgAMA1 lacks targeting information within its C-terminal cytoplasmic domain for microneme trafficking; it can bind aldolase in vitro, and residues responsible for aldolase binding are essential for TgAMA1 function during invasion (at the time of this study, before the later genetic evidence refuted aldolase's functional role).\",\n      \"method\": \"C-terminal domain truncation/mutation, trafficking assays, aldolase binding assay in vitro, invasion complementation assay\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, and the aldolase-binding-essential-for-invasion claim was subsequently refuted by Shen & Sibley 2014 (PMID 24550496)\",\n      \"pmids\": [\"20545864\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Bradyzoites invade host cells in an MJ-dependent fashion using AMA2 and AMA4 (paralogs of AMA1) rather than AMA1 itself. AMA4 plays a key role in cyst burden during chronic infection onset while being dispensable for the acute phase. AMA1-RON2 immunization provides strong protection against both acute and chronic infection.\",\n      \"method\": \"Immunofluorescence localization in bradyzoites, genetic knockout of AMA4, cyst burden quantification, mouse vaccination/challenge experiments\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with stage-specific functional readouts plus localization data distinguishing stage-specific MJ composition\",\n      \"pmids\": [\"36693095\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"TgAMA1 is a calcium-regulated microneme transmembrane protein that is secreted onto the parasite surface during invasion, where it functions as an adhesin by binding TgRON2 (inserted into the host cell membrane by rhoptry secretion) via a hydrophobic groove in its ectodomain, forming the core of the moving junction complex; this interaction protects AMA1 from constitutive rhomboid (ROM4/ROM5) intramembrane cleavage and triggers outside-in dephosphorylation of its cytoplasmic tail (Ser527), collectively promoting efficient parasite internalization, while the cytoplasmic tail released after cleavage also signals the parasite's switch to replication mode, and palmitoylation of AMA1 regulates its retention/secretion from micronemes.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TgAMA1 is a calcium-regulated type I transmembrane microneme protein of apicomplexan parasites that functions as the parasite-side adhesin at the moving junction (MJ), the ring-shaped structure through which the parasite penetrates its host cell [#0, #1, #3]. Following calcium-triggered microneme secretion, AMA1 relocates to the apical parasite surface, where its ectodomain binds the C-terminal region of the rhoptry neck protein RON2, which is itself inserted into the host cell membrane as part of a RON2/4/5/8 complex [#3, #6, #11, #12]. High-resolution crystallography defines the interaction: RON2 docks into a central hydrophobic groove of the AMA1 ectodomain, framed by conserved Trp/Tyr residues and gated by the mobile DII loop, forming an extensively buried, mechanically stable interface that anchors the junction against the forces of invasion [#9, #13, #21]. Conditional depletion and genetic knockout studies place AMA1's function after initial attachment: it promotes tight apposition to the host cell and efficient internalization and contributes to rhoptry discharge, but junction assembly and penetration can proceed at reduced efficiency in its absence, in part through compensatory upregulation of AMA/RON paralogs — establishing AMA1 as a critical but non-obligatory adhesin rather than an essential invasin [#2, #14, #16, #18]. AMA1 is subject to constitutive intramembrane cleavage within its transmembrane domain by the rhomboid proteases ROM4 and ROM5, and RON2 binding protects AMA1 from this cleavage while triggering outside-in dephosphorylation of Ser527 in its cytoplasmic tail; genetic evidence with cleavage-resistant and phosphomimetic alleles shows this regulated proteolysis and phosphorylation are tuned specifically to promote invasion [#4, #22, #23, #15]. Palmitoylation regulates AMA1 retention and secretion from micronemes [#20]. The AMA1–RON2 system is conserved across apicomplexans and diversified into stage-specific paralog pairs — sporozoites use sporoAMA1/sporoRON2 and bradyzoites use AMA2/AMA4 — and AMA1–RON2 immunization confers protection against acute and chronic infection [#5, #12, #17, #26].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Establishing whether AMA1 is essential for invasion and where it acts defined it as an apically-delivered, invasion-critical microneme protein whose secretion is calcium-controlled.\",\n      \"evidence\": \"IFA/IEM localization, biochemical fractionation, failed knockout, and antiserum invasion inhibition in T. gondii tachyzoites, plus calcium-ionophore secretion assays\",\n      \"pmids\": [\"11083833\", \"11087913\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular partner at the parasite surface not yet identified\", \"Mechanistic step of invasion controlled by AMA1 unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Conditional depletion pinpointed AMA1's action to after attachment — it is required for efficient invasion and rhoptry discharge but not microneme secretion or initial attachment.\",\n      \"evidence\": \"Regulatable-promoter conditional knockout with separate invasion, microneme, and rhoptry secretion assays in T. gondii RH\",\n      \"pmids\": [\"16000372\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How AMA1 links to rhoptry discharge machinery unknown\", \"Direct binding partner not yet defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identifying AMA1 in a complex with rhoptry neck (RON) proteins at the moving junction revealed the unexpected microneme–rhoptry collaboration that builds the invasion junction.\",\n      \"evidence\": \"Co-immunoprecipitation and immunoelectron microscopy localizing complex members to the MJ in T. gondii\",\n      \"pmids\": [\"16244709\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise RON partner engaging AMA1 directly not defined\", \"Membrane topology of the complex unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Characterizing AMA1 shedding showed it is cleaved by a rhomboid-like protease within its transmembrane domain, and that intact protein persists on newly invaded parasites — distinguishing it mechanistically from PfAMA1.\",\n      \"evidence\": \"Pulse-chase labeling, protease inhibitor studies, and heterologous Drosophila rhomboid cleavage assay in T. gondii\",\n      \"pmids\": [\"16102004\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Which endogenous rhomboid(s) cleave AMA1 not identified\", \"Functional consequence of cleavage unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstrating PfAMA1–PfRON4 co-precipitation established that the AMA1–RON association is conserved across apicomplexan parasites.\",\n      \"evidence\": \"Co-immunoprecipitation of native proteins in Plasmodium falciparum\",\n      \"pmids\": [\"16835460\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect nature of AMA1–RON4 contact unresolved\", \"Structural basis not addressed\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Resolving MJ topology showed RON2/4/5/8 are exported to the host membrane with RON4/5/8 on the cytoplasmic face while AMA1 sits in the parasite membrane, and that AMA1 pairs directly with RON2 independently of the other RONs.\",\n      \"evidence\": \"Metabolic labeling, immunoprecipitation, differential permeabilization, and antibody loading into host cells in T. gondii\",\n      \"pmids\": [\"19247437\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Region of RON2 binding AMA1 not yet mapped\", \"Structural interface undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Mapping the invasion-blocking mAb 4G2 epitope to the PfAMA1 hydrophobic groove (requiring Tyr251) showed that the RON-binding groove is the functional target of inhibitory antibodies.\",\n      \"evidence\": \"Antibody competition, site-directed mutagenesis of PfAMA1 Tyr251, and Co-IP in P. falciparum\",\n      \"pmids\": [\"19165323\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Full atomic interface not resolved in this study\", \"Single-residue analysis in one species\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"A genetic rescue with the released AMA1 cytoplasmic tail proposed that ROM4 cleavage of AMA1 triggers the switch from invasive to replicative mode — a model later revised.\",\n      \"evidence\": \"Conditional overexpression of dominant-negative TgROM4 rescued by AMA1 cytoplasmic-tail constructs, with replication assays (a 2025 erratum was subsequently issued)\",\n      \"pmids\": [\"21205639\", \"41379978\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Replication-switch interpretation contradicted by later invasion-specific data (#15)\", \"Downstream signaling of the released tail undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"The AMA1 ectodomain crystal structure defined a central hydrophobic groove framed by Trp353/Trp354/Tyr230 and gated by a short DII loop, giving an atomic candidate for the RON2 binding site.\",\n      \"evidence\": \"2.0 Å X-ray crystal structure of full-length TgAMA1 ectodomain\",\n      \"pmids\": [\"20304917\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Ligand-bound conformation not yet captured\", \"Function of the DII loop untested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Knockout of ROM4 showed rhomboid processing of AMA1 and other adhesins establishes the apical-posterior surface gradient needed for apical orientation, gliding, and MJ formation.\",\n      \"evidence\": \"Tetracycline-regulatable ROM4 conditional knockout with adhesin surface IFA, invasion, and motility assays in T. gondii\",\n      \"pmids\": [\"20421941\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ROM4 is the sole AMA1 protease unresolved (later addressed by #22)\", \"Coupling of surface gradient to junction formation mechanistically incomplete\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Defining the AMA1-binding region of RON2 (D3/D4 segments) and showing D3 peptide blocks invasion without preventing rhoptry injection established RON2 as the molecular bridge tethering AMA1 to the host-cell-anchored MJ, downstream of effector delivery.\",\n      \"evidence\": \"Recombinant RON2 fragment pull-downs, MJ localization, invasion inhibition with D3-GST, and evacuole assays in T. gondii; complementary interaction and topology mapping plus invasion inhibition in T. gondii and P. falciparum\",\n      \"pmids\": [\"21347354\", \"21347343\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-resolution interface not yet solved in these studies\", \"How the bridge withstands invasion forces unaddressed\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}, {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"AMA1 propeptide aliphatic residues were shown to be required for trafficking of AMA1 to the micronemes, defining the sorting determinant.\",\n      \"evidence\": \"Propeptide mutagenesis and GFP reporter trafficking assays in T. gondii\",\n      \"pmids\": [\"21438967\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor recognizing the propeptide signal not identified\", \"AMA1 finding embedded in a broader MIC propeptide study\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"The AMA1–RON2 peptide co-crystal structure revealed a stepwise assembly producing an extensive buried interface, explaining how the junction resists the mechanical forces of penetration.\",\n      \"evidence\": \"1.95 Å X-ray structure of TgAMA1 bound to a TgRON2 peptide\",\n      \"pmids\": [\"21778402\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Dynamics of assembly in the membrane not captured\", \"Contribution of the DII loop to selectivity not yet dissected\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Genetic dissection showed AMA1 is dispensable for RON4 ring formation and functional junction assembly but enhances apposition and internalization frequency, and that RON4 can act without AMA1 in Plasmodium sporozoites — decoupling junction assembly from AMA1.\",\n      \"evidence\": \"Conditional knockdown/knockout of AMA1 and RON4 with invasion assays and RON4 ring IFA in T. gondii and P. berghei\",\n      \"pmids\": [\"22177563\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"What supports residual invasion without AMA1 not yet identified (later attributed to paralogs, #18)\", \"Mechanism of the apposition enhancement unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Cleavage-resistant AMA1 knock-in alleles revealed that intramembrane proteolysis of AMA1 promotes invasion specifically — refuting the earlier replication-switch model.\",\n      \"evidence\": \"TM-domain mutagenesis, heterologous cleavage assays, and knock-in complementation of a conditional knockout with growth/invasion readouts in T. gondii\",\n      \"pmids\": [\"22523242\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise step of invasion enabled by cleavage not fully defined\", \"Reconciliation with the released-tail signaling proposal incomplete\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Deleting AMA1 across three zoite types in two species showed AMA1-null parasites are impaired in attachment but penetrate junctions normally, redefining AMA1 as a dispensable adhesin rather than an essential invasin.\",\n      \"evidence\": \"Genetic AMA1 deletion in Plasmodium sporozoites/merozoites and T. gondii RH tachyzoites, with assays separating attachment from penetration\",\n      \"pmids\": [\"24108241\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Compensating molecules not identified in this study\", \"Quantitative contribution of AMA1 to natural infection unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}, {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Discovery of exclusively self-pairing sporozoite paralogs sporoAMA1/sporoRON2, with allosteric conformational change on binding and stage-specific peptide inhibition, revealed stage-specialized AMA1–RON2 modules governing invasion in a life-cycle-specific manner.\",\n      \"evidence\": \"IFA localization, interaction-specificity binding assays, crystallography of the sporoAMA1–sporoRON2 complex, and stage-specific invasion inhibition in T. gondii\",\n      \"pmids\": [\"23940612\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Regulation of paralog expression across stages unresolved\", \"In vivo requirement of the sporozoite module untested here\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"AMA1 gene disruption triggering compensatory AMA/RON paralog upregulation explained residual invasion in AMA1-null parasites and demonstrated molecular plasticity in MJ architecture while confirming AMA1–RON2 maintains junction integrity.\",\n      \"evidence\": \"Reverse genetics, conditional complementation, IFA, Western blot for paralog upregulation, and invasion assays in T. gondii\",\n      \"pmids\": [\"24934579\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Trigger controlling paralog upregulation unknown\", \"Whether paralogs form structurally identical junctions unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Combining aldolase-binding mutants with an aldolase knockout established that the AMA1 cytoplasmic tail–aldolase interaction is dispensable for invasion — a negative result overturning the adhesin–motor linkage model for AMA1.\",\n      \"evidence\": \"In vitro tail–aldolase binding, mutagenesis, ALD conditional knockout, and gliding/invasion assays in T. gondii\",\n      \"pmids\": [\"24550496\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The actual force-transducing partner of the AMA1 tail unidentified\", \"Whether the tail engages the motor at all is unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Structural and biophysical analysis showed the DII loop acts as a gatekeeper controlling groove access and RON2-ligand selectivity, since its deletion permits high-affinity binding of a normally weak Eimeria RON2 peptide.\",\n      \"evidence\": \"ITC with a RON2 peptide panel, DII-loop deletion mutagenesis, and crystallography of the TgAMA1ΔDIIloop–EtRON2 complex\",\n      \"pmids\": [\"25955165\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological signal that repositions the DII loop unknown\", \"Selectivity role during natural cross-species interactions untested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Double-protease knockouts established that both ROM4 and ROM5 cleave AMA1, with ROM5 accounting for residual cleavage in the absence of ROM4, refining the identity of the responsible rhomboids.\",\n      \"evidence\": \"Cre and CRISPR-Cas9 knockouts of ROM4 and ROM5 with Western blot of AMA1 cleavage products and invasion/motility assays in T. gondii\",\n      \"pmids\": [\"25846828\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of each rhomboid during live invasion unresolved\", \"Regulation of cleavage timing not defined here\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identifying AMA1 palmitoylation and showing its blockade enhances release of AMA1 and other invasion proteins from micronemes established a lipid-modification switch controlling AMA1 retention/secretion.\",\n      \"evidence\": \"Acyl-RAC chemical proteomics, palmitoylation-site mutagenesis, and microneme secretion assays in T. gondii\",\n      \"pmids\": [\"26468752\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Palmitoyltransferase acting on AMA1 not identified\", \"Coupling of palmitoylation cycle to secretion signal unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showing that RON2 D3 binding protects AMA1 from rhomboid cleavage and drives dephosphorylation of tail Ser527, with a phosphomimetic S527D allele impairing invasion, established outside-in signaling through the AMA1–RON2 junction that couples ligand engagement to cleavage protection and tail phosphoregulation of invasion.\",\n      \"evidence\": \"Rhomboid cleavage assays ± D3 peptide, MS phosphorylation analysis, and allele-replacement genetics (phosphomimetic/phospho-null) with invasion assays in T. gondii\",\n      \"pmids\": [\"27624124\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase/phosphatase acting on Ser527 not identified\", \"Downstream effectors of the dephosphorylation signal undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Mapping stage-specific MJ composition showed bradyzoites invade using paralogs AMA2/AMA4 (AMA4 driving early cyst burden) rather than AMA1, and that AMA1–RON2 immunization protects against acute and chronic infection, extending AMA1 biology to chronic-stage invasion and vaccine potential.\",\n      \"evidence\": \"Bradyzoite IFA, AMA4 knockout with cyst-burden quantification, and mouse vaccination/challenge with AMA1-RON2 in T. gondii\",\n      \"pmids\": [\"36693095\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Regulatory basis of stage-specific paralog usage unknown\", \"Structural interface of bradyzoite AMA paralogs unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The identity of the cytoplasmic effectors that transduce AMA1 tail dephosphorylation and cleaved-tail signaling into invasion outcomes, and the regulatory logic governing stage-specific AMA/RON paralog deployment, remain open.\",\n      \"evidence\": \"No timeline discovery identifies the kinase/phosphatase or downstream signaling partners of the AMA1 tail, nor the transcriptional/post-transcriptional control of paralog switching\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Ser527 kinase and phosphatase unidentified\", \"Force-transducing partner of the AMA1 cytoplasmic tail unknown\", \"Mechanism selecting AMA1 vs. paralogs across life-cycle stages undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0050839\", \"supporting_discovery_ids\": [3, 11, 12, 13], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0005178\", \"supporting_discovery_ids\": [0, 2, 16], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0042803\", \"supporting_discovery_ids\": [9, 13, 21], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0020009\", \"supporting_discovery_ids\": [0, 24], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0009986\", \"supporting_discovery_ids\": [0, 4], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0016021\", \"supporting_discovery_ids\": [0, 4, 6], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0033644\", \"supporting_discovery_ids\": [3, 6, 13], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0044409\", \"supporting_discovery_ids\": [0, 2, 16, 18], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0006508\", \"supporting_discovery_ids\": [4, 15, 22, 23], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0018345\", \"supporting_discovery_ids\": [20], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0006836\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\n      \"Moving junction complex (AMA1 with RON2/RON4/RON5/RON8)\",\n      \"TgAMA1–TgRON2 core adhesion pair\",\n      \"sporoAMA1–sporoRON2 sporozoite-stage complex\",\n      \"AMA2/AMA4-based bradyzoite moving junction\"\n    ],\n    \"partners\": [\n      \"RON2 (RON2 C-terminal D3/D4 region; direct ligand in hydrophobic groove)\",\n      \"RON4\",\n      \"RON5\",\n      \"RON8\",\n      \"ROM4 (rhomboid protease; cleaves AMA1 TM domain)\",\n      \"ROM5 (rhomboid protease; residual AMA1 cleavage)\",\n      \"Fructose-1,6-bisphosphate aldolase (ALD; binds cytoplasmic tail in vitro but dispensable for invasion)\"\n    ],\n    \"other_free_text\": [\n      \"Type I transmembrane protein with an ectodomain (domains I/II/III), a central hydrophobic RON2-binding groove framed by Trp353/Trp354/Tyr230, and a mobile DII loop acting as a selectivity gatekeeper.\",\n      \"Cytoplasmic tail carries a regulatory phosphosite (Ser527); RON2 binding drives its dephosphorylation and a phosphomimetic S527D allele impairs invasion (outside-in signaling).\",\n      \"Secretion from micronemes is calcium-regulated and further tuned by palmitoylation; propeptide aliphatic residues direct microneme trafficking.\",\n      \"Functionally a critical but dispensable adhesin: null parasites retain junction-mediated penetration, and loss is buffered by compensatory upregulation of AMA/RON paralogs.\",\n      \"Stage-specific paralog usage: tachyzoites use AMA1, sporozoites use sporoAMA1/sporoRON2, bradyzoites use AMA2/AMA4.\",\n      \"AMA1–RON2 immunization protects against acute and chronic Toxoplasma infection.\",\n      \"The 2010 replication-switch model for cleaved AMA1 tail (#8) was revised by later invasion-specific genetic evidence (#15); the #8 paper also carries a 2025 erratum.\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_255260","name":"AMA1","product":"apical membrane antigen AMA1","uniprot_acc":"S8GKS3","chromosome":"TGME49_chrVIIb","start_pos":4947538},{"strain":"GT1","gene_id":"TGGT1_255260","name":null,"product":"apical membrane antigen AMA1","uniprot_acc":null,"chromosome":"TGGT1_chrVIIb","start_pos":4856406},{"strain":"RH88","gene_id":"TGRH88_073680","name":null,"product":"apical membrane antigen AMA1","uniprot_acc":null,"chromosome":"CM023089","start_pos":4982244},{"strain":"VEG","gene_id":"TGVEG_255260","name":"AMA1","product":"apical membrane antigen AMA1","uniprot_acc":"B6KAM0","chromosome":"TGVEG_chrVIIb","start_pos":4969545}]}