{"gene":"TG_275470","gene_symbol":"GRA15","run_date":"2026-09-08T16:59:57+00:00","timeline":{"discoveries":[{"year":2011,"finding":"GRA15 is a novel dense granule protein secreted by Toxoplasma gondii into the host cell upon invasion, and the type II allele is sufficient to activate NF-κB nuclear translocation and NF-κB-mediated transcription in host cells. A GRA15-deficient type II strain has a severe defect in NF-κB activation, and human cells expressing type II GRA15 activate NF-κB, demonstrating GRA15 alone is sufficient for this effect.","method":"Forward genetics (type II × type III cross), GRA15 knockout, stable expression of GRA15II in type I strain and human cells, NF-κB reporter assays, in vivo bioluminescent imaging","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (forward genetics, KO, heterologous expression), replicated across cell types, founding paper with rigorous controls","pmids":["21199955"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (ME49/Prugniaud), type I (RH), type III"}]},{"year":2011,"finding":"GRA15 (activating NF-κB) promotes classical (M1) macrophage activation by type II parasites, whereas ROP16 (activating STAT6) promotes alternative (M2) macrophage activation. GRA15 and ROP16 antagonistically regulate many of the same host genes, and their combined expression determines intestinal inflammation and parasite control in vivo.","method":"Macrophage polarization assays, genetic crosses, transgenic parasite expression, in vivo oral infection model","journal":"Cell host & microbe","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal approaches across two independent labs, epistasis confirmed in vivo","pmids":["21669396"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2011,"finding":"GRA15 (along with ROP16 and ROP18) is one of three parasitic factors that determine strain-specific accumulation of murine GBP1 on the parasitophorous vacuole (PV) in IFN-γ-activated cells; GRA15 contributes to GBP recruitment, linking it to the cell-autonomous immune response.","method":"Genetic crosses, transgenic parasite expression, immunofluorescence for mGBP1 localization on PV","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiments with transgenic parasites, single lab, multiple genetic tools","pmids":["21931713"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2013,"finding":"GRA15 is responsible for IL-1β induction during T. gondii infection of human monocytes, acting upstream of caspase-1 and ASC (inflammasome components). A GRA15-knockout type II strain failed to induce IL-1β, and a type I strain expressing type II GRA15 gained the ability to induce IL-1β, establishing GRA15 as the parasite factor driving NF-κB-dependent IL-1β transcription.","method":"GRA15 knockout, stable transgenic expression of GRA15II in type I strain, shRNA knockdown of caspase-1 and ASC, IL-1β ELISA and transcript analysis","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal gain/loss-of-function with multiple orthogonal methods, caspase-1/ASC knockdown epistasis","pmids":["23839215"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II (Prugniaud)"}]},{"year":2013,"finding":"ROP16 and GRA15 act in combination to promote host resistance to oral Toxoplasma infection; expression of STAT-activating ROP16 in type II strain promotes host resistance only when endogenous GRA15 is also present, and co-expression enhances parasite susceptibility in IFN-γ/TNF-stimulated macrophages.","method":"Transgenic parasite expression (type II + ROP16I), GRA15 genetic background, oral infection model, STAT3/6-deficient mice, macrophage killing assays","journal":"Infection and immunity","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with defined transgenic strains, multiple in vivo and in vitro readouts","pmids":["23545295"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud), type I"}]},{"year":2013,"finding":"GRA15 polymorphisms between RH and GT1 type I strains account for differential NF-κB activation between these strains. Furthermore, RH (but not other type I strains) recruits phosphorylated IκBα to the parasitophorous vacuole membrane in a manner partially dependent on GRA2.","method":"Whole genome sequencing (SNP identification), host transcriptional profiling, NF-κB activation assays, immunofluorescence for p-IκBα","journal":"BMC genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — comparative genomics plus functional validation, single lab","pmids":["23837824"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RH (type I), GT1 (type I)"}]},{"year":2014,"finding":"Type II GRA15 induces expression of CD40 on infected macrophages in an NF-κB-dependent manner. Stable expression of HA-tagged GRA15II in THP-1 cells upregulated CD40 in the absence of infection. CD40 induction was mapped by forward genetics to a chromosomal region containing GRA15, and CD40L engagement of GRA15II-induced CD40 amplified the IL-12 response.","method":"Forward genetics (type II × type III cross), stable GRA15II expression in type I parasites and THP-1 cells, NF-κB inhibitor treatment, CD40 flow cytometry, IL-12 ELISA","journal":"Infection and immunity","confidence":"High","confidence_rationale":"Tier 2 / Strong — forward genetics plus heterologous expression, NF-κB inhibitor epistasis, multiple orthogonal methods","pmids":["25024369"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2014,"finding":"GRA15 and ROP16 from Hammondia hammondi are functionally conserved; HhGRA15 modulates host NF-κB pathway when expressed heterologously in T. gondii, confirming that GRA15's NF-κB-activating function is conserved across closely related apicomplexans.","method":"Heterologous expression of HhGRA15 in T. gondii, NF-κB reporter assays","journal":"Eukaryotic cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional heterologous expression assay, single lab","pmids":["25280815"],"is_preprint":false,"attribution":[{"species":"Hammondia hammondi","strain":""},{"species":"Toxoplasma gondii","strain":""}]},{"year":2019,"finding":"GRA15 activates the NF-κB pathway by interacting with TNF receptor-associated factors (TRAFs). Multiple TRAF-binding sites were identified in the GRA15 amino acid sequence; deletion of these sites greatly reduces NF-κB activation. TRAF2 knockout cells display impaired GRA15-mediated NF-κB activation, establishing TRAF proteins as the molecular link between GRA15 and NF-κB.","method":"Co-immunoprecipitation (GRA15–TRAF interaction), TRAF-binding site deletion mutagenesis, TRAF2 knockout cells, NF-κB reporter assays","journal":"mBio","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — mutagenesis of binding sites combined with KO cell lines and reporter assays, multiple orthogonal methods in one rigorous study","pmids":["31311877"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2019,"finding":"GRA15 is secreted into the host cell cytoplasm and localizes to the endoplasmic reticulum via its second transmembrane motif. GRA15 promotes STING polyubiquitination at Lys-337 and STING oligomerization in a TRAF-dependent manner, thereby activating STING and innate immune signaling (type I IFNs). GRA15-deficient T. gondii failed to activate STING-dependent responses and was more virulent in wild-type but not Stinggt/gt mice.","method":"GRA15 subcellular fractionation/localization (ER), transmembrane domain mutants, STING polyubiquitination assay, STING oligomerization assay, GRA15-KO parasites, Stinggt/gt mice infection","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (localization, biochemical ubiquitination assay, KO parasites, genetic host model), single lab but comprehensive","pmids":["31416833"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2018,"finding":"GRA15-dependent NF-κB activation induces NLRP3 inflammasome-dependent IL-1β production from infected monocytes; IL-1β in turn combines with IFN-γ to strongly stimulate iNOS in hepatocytes, which reduces IDO1 expression, a key IFN-γ-inducible anti-Toxoplasma effector. Thus GRA15 indirectly suppresses IFN-γ-induced IDO1-mediated cell-autonomous immunity in humans by upregulating iNOS.","method":"GRA15-KO parasites, monocyte-hepatocyte co-culture, iNOS inhibition, NLRP3 inflammasome inhibition, IDO1 expression analysis","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — GRA15-KO with defined cellular epistasis across two cell types, inhibitor validation, multiple orthogonal approaches","pmids":["30301855"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"finding":"GRA15 mediates recruitment of ubiquitin ligases TRAF2 and TRAF6 to the parasitophorous vacuole membrane in human primary fibroblasts, which enhances recruitment of ubiquitin receptors (p62/NDP52) and ubiquitin-like molecules (LC3B, GABARAP), ultimately leading to lysosomal degradation of the vacuole. In murine fibroblasts, GRA15-mediated TRAF6 recruitment leads to recruitment of immunity-related GTPases and vacuole destruction.","method":"GRA15-KO parasites, immunofluorescence for TRAF2/TRAF6/p62/NDP52/LC3B/GABARAP at PV, lysosomal degradation assays, murine vs. human fibroblast comparison","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — GRA15-KO with mechanistic follow-up across two species' cells, multiple markers, defined pathway","pmids":["32293748"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"finding":"GRA15 and GRA24 synergistically shape innate immune responses in Tlr11-/- mice and human macrophages; GRA15 is the predominant effector for IL-12, IL-18, and IL-1β secretion in these contexts. GRA15/GRA24-mediated cytokine induction activates IFN-γ secretion by PBMCs, which controls Toxoplasma proliferation.","method":"GRA15 and GRA24 single/double KO parasites, Tlr11-/- mice infection, human macrophage infection, cytokine ELISAs, PBMC IFN-γ assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with epistasis, multiple host models (KO mice, human macrophages), multiple cytokine readouts","pmids":["32453782"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"finding":"GRA15, GRA7, and GRA14 are all involved in NF-κB activation in type II T. gondii; GRA15 is essential for NF-κB activation (nuclear translocation of RelA, phosphorylation of IκBα), while GRA7 and GRA14 only partially contribute. Deletion of GRA15 in Pru strain reduces IL-6 and shows predominantly downregulated NF-κB-mediated gene expression.","method":"Luciferase NF-κB reporter screen, GRA15/GRA7/GRA14 KO in Pru strain, immunofluorescence for RelA nuclear translocation, IκBα phosphorylation western blot, RNA-seq","journal":"Frontiers in immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO parasites with multiple biochemical and transcriptomic readouts, luciferase screen for mechanism","pmids":["32849602"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2017,"finding":"Yeast two-hybrid screening identified mouse Luzp1 and AW209491 as host binding proteins that interact with GRA15II.","method":"Yeast two-hybrid screen with mouse cDNA library using GRA15II as bait, western blot validation of bait expression","journal":"Parasites & vectors","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single yeast two-hybrid screen, no co-IP validation or functional follow-up in the abstract","pmids":["28049510"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"PRU (type II)"}]},{"year":2012,"finding":"GRA15 and ROP16 differentially modulate specific aspects of IFN-γ signaling: GRA15 activates NF-κB/IRF1 to modulate expression of a subset of IFN-γ-responsive genes, while ROP16 activates STAT3/6 to modulate a different subset. However, all three clonal lineages equally inhibit STAT1 transcriptional activity, indicating STAT1 inhibition is independent of GRA15 or ROP16.","method":"Stable STAT1-specific reporter cell line, transcriptional profiling, GRA15/ROP16 allele comparisons across clonal types","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assays with genetic comparisons, single lab, two orthogonal readouts","pmids":["23240025"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2019,"finding":"GRA15-dependent suppression of IFN-γ-induced IDO1 anti-parasite response operates in human neuronal cell lines and primary human neurons, in addition to hepatocytes and monocytes; the mechanism involves GRA15-induced IL-1β production leading to iNOS-dependent IDO1 suppression in brain cells.","method":"Type II T. gondii-infected THP-1 monocytes co-cultured with neuronal cell lines/primary neurons, GRA15-KO comparison, IDO1 expression assays, IL-1β and iNOS measurements","journal":"Frontiers in cellular and infection microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — GRA15-KO epistasis in co-culture system, single lab, consistent with prior mechanistic framework","pmids":["31119110"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2021,"finding":"GRA15 is important for increased expression of IL-1β and other IL-1 pathway host genes in the brains of toxoplasmic encephalitic mice; QTL mapping identified GRA15 as the Toxoplasma gene in a locus correlating with seizure onset. Inhibiting IL-1 receptor signaling reduced seizure severity.","method":"QTL mapping, GRA15-KO parasites, mouse brain gene expression analysis, IL-1 receptor inhibitor treatment, seizure scoring","journal":"mBio","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — QTL mapping plus GRA15-KO functional validation in vivo, single lab","pmids":["34154412"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2021,"finding":"GRA15 is required for inflammasome-induced IL-1β release during T. gondii infection; knocking out GRA15 in Δmag1 parasites completely inhibited IL-1β release, indicating GRA15 is the primary driver of IL-1β induction (which MAG1 counteracts). This confirms GRA15's role in inflammasome activation during infection.","method":"Δmag1, Δgra15, and Δmag1/Δgra15 double-KO parasites, BMDM infection, IL-1β ELISA, heterologous MAG1 complementation","journal":"mBio","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — double KO epistasis with complementation, single lab, clean genetic dissection","pmids":["34006649"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2022,"finding":"GRA15 induces ICAM-1 expression on infected dendritic cells via NF-κB signaling, which promotes enhanced cell adhesion and trans-endothelial migration (TEM). GRA15 deletion or Icam-1 gene silencing reduced TEM, while TgWIP (separately) also facilitates TEM through regulation of host actin dynamics.","method":"GRA15-KO parasites, siRNA silencing of Icam-1 in primary DCs, TEM assay across polarized brain endothelial monolayers, immunofluorescence for ICAM-1","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — GRA15-KO and gene silencing with functional TEM readout, single lab","pmids":["35990682"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2024,"finding":"GRA15 promotes CCR7-mediated macrophage chemotaxis by acting on the NF-κB signaling pathway. GRA15 and GRA24 (acting on NF-κB and p38 MAPK, respectively) together with GRA28-boosted chromatin accessibility at the Ccr7 gene locus drive parasite dissemination in vivo. In vivo, macrophages infected with a GRA15/GRA24 double mutant had reduced migration to secondary organs compared to WT-infected macrophages.","method":"GRA15/GRA24 double-KO parasites, CCR7 expression assays, adoptive transfer of macrophages in mice, chromatin accessibility assay (ATAC-seq), NF-κB reporter assays","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — double KO with in vivo adoptive transfer, ATAC-seq, and signaling pathway dissection; multiple orthogonal methods","pmids":["39207098"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2022,"finding":"A newly isolated type 1 strain (T.gHB1/ToxoDB#10) carries a structurally distinct GRA15 with only one transmembrane region and an extended C-terminal region. This GRA15 activates NF-κB through IκBα phosphorylation and p65 nuclear translocation; deletion mapping showed that residues 194–518 of T.gHB1 GRA15 are required for NF-κB activation.","method":"NF-κB reporter assays, western blot for IκBα phosphorylation and p65 nuclear translocation, truncation/deletion mutagenesis of GRA15","journal":"Parasites & vectors","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutagenesis with functional reporter assays, single lab, single strain","pmids":["36175964"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"T.gHB1 (ToxoDB#10, type I)"}]},{"year":2018,"finding":"GRA15II expressed in choriocarcinoma JEG-3 cells induces endoplasmic reticulum stress (ERS) via IRE1α/JNK pathway and subsequently causes apoptosis; inhibition of IRE1α or JNK reduced GRA15II-induced apoptosis and decreased TRAF2 and ASK1 activation.","method":"Transfection of pEGFP-GRA15II into JEG-3 cells, IRE1α inhibitor (4μ8C) and JNK inhibitor (SP6000125), western blot for apoptosis/ERS markers, flow cytometry","journal":"Parasites & vectors","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — pharmacological inhibitors with multiple apoptosis/ERS markers, single lab, heterologous expression system","pmids":["29665822"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (PRU)"}]},{"year":2024,"finding":"GRA15 expression in dendritic cells (but not macrophages) suppresses T cell-mediated humoral immunity; conditional knock-in mice expressing GRA15 specifically in CD11c+ dendritic cells (CD11c-Cre/GRA15cKI) produced lower anti-T. gondii and anti-OVA antibody titers and had reduced numbers of antigen-specific T cells.","method":"Conditional knock-in mice (CD11c-Cre/GRA15cKI and macrophage-specific), infection and OVA immunization, antibody titer measurements, flow cytometry for plasma cells and T cells","journal":"Parasitology international","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific conditional knock-in model with functional immune readouts, single lab","pmids":["39557359"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2026,"finding":"GRA15 drives transcriptional and secretory upregulation of CCL5/RANTES in primary brain endothelial cells and dendritic cells through NF-κB signaling. CCL5 induces hypermotility and chemotaxis of infected DCs and enhances their transmigration across endothelial monolayers. In vivo, GRA15-driven CCL5 increases sequestration of infected DCs in brain microvasculature and cerebral parasite loads; CCR5 antagonist (Maraviroc) reversed sequestration.","method":"GRA15-KO parasites, NF-κB reporter assay, CCL5 ELISA, DC transmigration assay, in vivo mouse infection with Maraviroc treatment, intravital microscopy of cerebral microvasculature","journal":"mBio","confidence":"High","confidence_rationale":"Tier 2 / Strong — GRA15-KO with in vitro mechanistic dissection, in vivo pharmacological validation, multiple orthogonal readouts in one study","pmids":["41528135"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2025,"finding":"GRA15 and TgWIP effectors increase the sequestration of parasitized dendritic cells in cortical capillaries and cerebral parasite loads in a strain-dependent manner following intracarotid delivery; post-replicative egress from sequestered DCs enables rapid parasite localization in cortical neurons.","method":"GRA15-KO and TgWIP-KO parasites, intracarotid arterial delivery into mice, in vivo brain imaging, ICAM-1/CD18 blocking antibody treatment","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO parasites with in vivo intravascular delivery model, single lab","pmids":["40229286"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"type I (RH), type II (PRU/ME49), type III"}]}],"current_model":"GRA15 is a polymorphic dense granule protein secreted by Toxoplasma gondii into the host cell cytoplasm, where it localizes to the endoplasmic reticulum via its second transmembrane domain and activates the NF-κB pathway by directly interacting with TRAF adaptor proteins (including TRAF2 and TRAF6) through defined TRAF-binding sites; this drives classical macrophage activation, IL-1β/IL-12/IL-18 production, STING polyubiquitination and activation, ICAM-1 and CCL5 induction in dendritic cells and brain endothelium, GBP/IRG recruitment to the parasitophorous vacuole, and CCR7-mediated macrophage chemotaxis—collectively regulating parasite dissemination, cell-autonomous immunity, neuroinflammation, and seizure susceptibility in a strain-specific (predominantly type II allele) manner."},"narrative":{"mechanistic_narrative":"GRA15 is a polymorphic dense granule protein secreted by Toxoplasma gondii into the host cell upon invasion, where it functions as the parasite's principal activator of the host NF-κB pathway and thereby reprograms innate immunity, inflammation, and parasite dissemination [PMID:21199955]. Secreted GRA15 traffics to the host endoplasmic reticulum via its second transmembrane motif and drives NF-κB activation—IκBα phosphorylation, RelA/p65 nuclear translocation, and NF-κB-dependent transcription—by directly binding TNF-receptor-associated factors (TRAFs) through defined TRAF-binding sites, with TRAF2 required for full activity [PMID:31311877, PMID:31416833, PMID:32849602]. Through this NF-κB axis GRA15 promotes classical (M1) macrophage activation in antagonism with the STAT-activating effector ROP16 [PMID:21669396], and induces a broad inflammatory program including IL-1β, IL-12, IL-18, IL-6, and CD40 [PMID:23839215, PMID:25024369, PMID:32453782]. GRA15-driven, NLRP3/caspase-1/ASC-dependent IL-1β production couples the parasite to inflammasome signaling and, via IL-1β–iNOS induction, indirectly suppresses IFN-γ-induced IDO1 anti-parasite defense in hepatocytes and neurons [PMID:23839215, PMID:30301855, PMID:31119110, PMID:34006649]. At the parasitophorous vacuole, GRA15 recruits TRAF2 and TRAF6 and downstream ubiquitin receptors and ubiquitin-like molecules to target the vacuole for lysosomal degradation and immunity-related GTPase attack, and promotes STING polyubiquitination and oligomerization to activate type I IFN responses [PMID:31416833, PMID:32293748]. GRA15 also induces ICAM-1, CCL5/RANTES, and CCR7 in dendritic cells and brain endothelium to enhance infected-cell chemotaxis, transendothelial migration, and cerebral sequestration, and its IL-1-driven neuroinflammation increases seizure susceptibility [PMID:34154412, PMID:35990682, PMID:39207098, PMID:41528135]. These activities are predominantly encoded by the type II allele, and allelic polymorphism accounts for strain-specific NF-κB output [PMID:21199955, PMID:23837824].","teleology":[{"year":2011,"claim":"Established that a secreted parasite dense granule protein—not merely host recognition—is sufficient to activate host NF-κB, identifying GRA15 as the strain-specific driver of this response.","evidence":"Forward genetics from a type II × type III cross, GRA15 knockout, and heterologous GRA15II expression in a type I strain and human cells with NF-κB reporter assays","pmids":["21199955"],"confidence":"High","gaps":["Molecular mechanism linking GRA15 to NF-κB not yet defined","Subcellular localization of GRA15 in the host cell not established"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (ME49/Prugniaud), type I (RH), type III"}]},{"year":2011,"claim":"Placed GRA15 within a broader immunomodulatory logic by showing it drives M1 macrophage polarization in antagonism with ROP16-driven M2 polarization, jointly determining intestinal inflammation and parasite control.","evidence":"Macrophage polarization assays, genetic crosses, transgenic expression, and in vivo oral infection","pmids":["21669396"],"confidence":"High","gaps":["Direct GRA15 effector partners not identified","How opposing NF-κB and STAT6 signals are integrated on shared genes unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2011,"claim":"Linked GRA15 to cell-autonomous immunity by showing it contributes to strain-specific recruitment of murine GBP1 to the parasitophorous vacuole.","evidence":"Genetic crosses, transgenic parasites, and immunofluorescence for mGBP1 at the PV","pmids":["21931713"],"confidence":"Medium","gaps":["Mechanism connecting GRA15/NF-κB to GBP recruitment not defined","Relative contribution versus ROP18/ROP16 unclear"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2012,"claim":"Resolved which arms of IFN-γ signaling GRA15 controls, showing it modulates an NF-κB/IRF1-dependent gene subset while STAT1 inhibition occurs independently of GRA15.","evidence":"STAT1 reporter cell line and transcriptional profiling across clonal lineages with GRA15/ROP16 allele comparisons","pmids":["23240025"],"confidence":"Medium","gaps":["The GRA15-independent STAT1 inhibitor not identified","Direct IRF1 engagement not mechanistically tested"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2013,"claim":"Identified GRA15 as the parasite factor driving inflammasome-associated IL-1β, acting upstream of caspase-1/ASC via NF-κB-dependent transcription in human monocytes.","evidence":"Reciprocal GRA15 knockout and gain-of-function expression with caspase-1/ASC knockdown and IL-1β measurement","pmids":["23839215"],"confidence":"High","gaps":["Which inflammasome sensor is engaged not defined here","Direct GRA15 interactors upstream of NF-κB not identified"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II (Prugniaud)"}]},{"year":2013,"claim":"Demonstrated GRA15 polymorphism explains differential NF-κB output even within type I strains, and that RH additionally recruits phospho-IκBα to the PV membrane partly via GRA2.","evidence":"Whole-genome SNP identification, host transcriptional profiling, NF-κB assays, and p-IκBα immunofluorescence","pmids":["23837824"],"confidence":"Medium","gaps":["Specific GRA15 residues responsible for RH/GT1 divergence not mapped","Relationship between PV-localized p-IκBα and cytoplasmic GRA15 function unclear"],"attribution":[{"species":"Toxoplasma gondii","strain":"RH (type I), GT1 (type I)"}]},{"year":2013,"claim":"Showed GRA15 and ROP16 cooperate genetically to promote host resistance to oral infection, refining the two effectors from purely antagonistic to context-dependent partners.","evidence":"Transgenic type II + ROP16I parasites on defined GRA15 backgrounds, oral infection, STAT-deficient mice, and macrophage killing assays","pmids":["23545295"],"confidence":"High","gaps":["Molecular basis of GRA15/ROP16 cooperativity not defined","Effector-specific gene targets governing resistance not enumerated"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud), type I"}]},{"year":2014,"claim":"Extended the GRA15 NF-κB program to costimulatory signaling by mapping NF-κB-dependent CD40 induction to GRA15, amplifying IL-12 responses.","evidence":"Forward genetics, heterologous GRA15II expression in THP-1, NF-κB inhibitor epistasis, and CD40/IL-12 readouts","pmids":["25024369"],"confidence":"High","gaps":["Whether CD40 induction is direct or via secondary cytokines untested","In vivo relevance of CD40 amplification not addressed"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I, type II, type III"}]},{"year":2014,"claim":"Demonstrated evolutionary conservation of GRA15's NF-κB-activating function in the sister species Hammondia hammondi.","evidence":"Heterologous expression of HhGRA15 in T. gondii with NF-κB reporter assays","pmids":["25280815"],"confidence":"Medium","gaps":["Conservation of downstream partners in H. hammondi not tested","Native H. hammondi host response not examined"],"attribution":[{"species":"Hammondia hammondi","strain":""},{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"First attempt to identify direct host binding partners of GRA15, nominating mouse Luzp1 and AW209491.","evidence":"Yeast two-hybrid screen using GRA15II as bait against a mouse cDNA library","pmids":["28049510"],"confidence":"Low","gaps":["No co-IP or reciprocal validation of the interactions","No functional link between these partners and NF-κB established"],"attribution":[{"species":"Toxoplasma gondii","strain":"PRU (type II)"}]},{"year":2018,"claim":"Connected GRA15-driven IL-1β to suppression of host defense by showing IL-1β plus IFN-γ upregulates iNOS, which reduces the anti-Toxoplasma effector IDO1.","evidence":"GRA15-KO parasites in monocyte-hepatocyte co-culture with NLRP3 and iNOS inhibition and IDO1 readouts","pmids":["30301855"],"confidence":"High","gaps":["Molecular mechanism of iNOS-mediated IDO1 suppression not fully defined","Systemic in vivo consequence of IDO1 suppression not tested here"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2018,"claim":"Showed heterologously expressed GRA15II can trigger ER stress via IRE1α/JNK and TRAF2/ASK1 activation, linking GRA15 to apoptotic signaling in placental cells.","evidence":"Transfection of GRA15II into JEG-3 cells with IRE1α and JNK inhibitors and apoptosis/ER stress marker western blots","pmids":["29665822"],"confidence":"Medium","gaps":["Heterologous overexpression may not reflect secreted GRA15 during infection","Relationship to NF-κB activation and TRAF binding not directly reconciled"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (PRU)"}]},{"year":2019,"claim":"Defined the molecular mechanism of GRA15-mediated NF-κB activation by identifying TRAF-binding sites in GRA15 and showing TRAF2 is required.","evidence":"Co-immunoprecipitation of GRA15–TRAF, TRAF-binding site deletion mutagenesis, TRAF2 knockout cells, and NF-κB reporter assays","pmids":["31311877"],"confidence":"High","gaps":["Stoichiometry and structure of the GRA15-TRAF complex not resolved","Which additional TRAFs act redundantly not fully mapped"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2019,"claim":"Localized GRA15 to the host ER via its second transmembrane motif and showed it promotes TRAF-dependent STING polyubiquitination and oligomerization to activate type I IFN.","evidence":"Subcellular fractionation, transmembrane domain mutants, STING ubiquitination/oligomerization assays, GRA15-KO parasites, and Stinggt/gt mice","pmids":["31416833"],"confidence":"High","gaps":["Direct versus indirect action of GRA15 on the STING ubiquitination machinery unresolved","Identity of the ubiquitin ligase modifying STING Lys-337 not defined"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2019,"claim":"Generalized the GRA15–IL-1β–iNOS–IDO1 axis to brain cells, showing GRA15 suppresses IFN-γ-induced IDO1 in human neurons.","evidence":"GRA15-KO comparison in monocyte-neuron co-cultures with IL-1β, iNOS, and IDO1 measurements","pmids":["31119110"],"confidence":"Medium","gaps":["Neuron-intrinsic versus monocyte-derived signaling not fully separated","In vivo brain relevance not tested in this study"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"claim":"Established GRA15 as the recruiter of TRAF2/TRAF6 to the PV membrane, seeding ubiquitin receptors and ubiquitin-like conjugates that drive lysosomal and IRG-mediated vacuole destruction, with species-specific outcomes.","evidence":"GRA15-KO parasites with immunofluorescence for TRAF2/TRAF6/p62/NDP52/LC3B/GABARAP and lysosomal degradation assays in human versus murine fibroblasts","pmids":["32293748"],"confidence":"High","gaps":["How ER-localized GRA15 delivers TRAFs to the PV membrane unclear","Determinants of the divergent human versus mouse outcomes not fully defined"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"claim":"Showed GRA15 is the predominant effector for IL-12/IL-18/IL-1β secretion and, with GRA24, drives IFN-γ production that controls parasite proliferation.","evidence":"GRA15/GRA24 single and double KO parasites, Tlr11-/- mice, human macrophages, and PBMC IFN-γ assays","pmids":["32453782"],"confidence":"High","gaps":["Molecular basis of GRA15/GRA24 synergy not defined","Contribution of individual cytokines to IFN-γ induction not dissected"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2020,"claim":"Confirmed GRA15 as the essential NF-κB activator among dense granule proteins, with GRA7 and GRA14 only partially contributing, and mapped its transcriptional footprint.","evidence":"Luciferase NF-κB reporter screen, GRA15/GRA7/GRA14 KO in Pru, RelA translocation and IκBα phosphorylation, and RNA-seq","pmids":["32849602"],"confidence":"High","gaps":["How GRA7/GRA14 contribute mechanistically not defined","Full set of NF-κB target genes governing outcome not prioritized"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2021,"claim":"Connected GRA15 to neuropathology by mapping it as the parasite gene driving brain IL-1 pathway induction and seizure susceptibility.","evidence":"QTL mapping, GRA15-KO parasites, brain gene expression, and IL-1 receptor inhibition with seizure scoring","pmids":["34154412"],"confidence":"Medium","gaps":["Cell types responsible for brain IL-1β induction not fully defined","Direct causal chain from GRA15 to seizure circuitry unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2021,"claim":"Genetically dissected the inflammasome axis, showing GRA15 is the primary driver of IL-1β release that MAG1 counteracts.","evidence":"Δmag1, Δgra15, and double-KO parasites with BMDM IL-1β ELISA and MAG1 complementation","pmids":["34006649"],"confidence":"Medium","gaps":["Mechanism by which MAG1 antagonizes GRA15-driven IL-1β not defined","Whether antagonism occurs at transcription or inflammasome assembly unclear"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2022,"claim":"Showed GRA15-driven NF-κB induces ICAM-1 on infected dendritic cells to promote adhesion and transendothelial migration, implicating GRA15 in parasite dissemination.","evidence":"GRA15-KO parasites, Icam-1 siRNA silencing in primary DCs, and transendothelial migration assays across brain endothelium","pmids":["35990682"],"confidence":"Medium","gaps":["Contribution of ICAM-1 versus other NF-κB targets to migration not quantified","In vivo dissemination consequence tested separately"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2022,"claim":"Revealed GRA15 structural diversity by characterizing a type I strain with a single-transmembrane, C-terminally extended GRA15 that still activates NF-κB, mapping the required region to residues 194–518.","evidence":"NF-κB reporter assays, IκBα phosphorylation and p65 translocation western blots, and truncation mutagenesis of T.gHB1 GRA15","pmids":["36175964"],"confidence":"Medium","gaps":["Whether the single-TM variant still localizes to ER not tested","TRAF-binding requirement of this variant not directly examined"],"attribution":[{"species":"Toxoplasma gondii","strain":"T.gHB1 (ToxoDB#10, type I)"}]},{"year":2024,"claim":"Established GRA15 as a driver of infected-cell motility for dissemination by inducing CCR7-mediated macrophage chemotaxis via NF-κB, cooperating with GRA24 and GRA28.","evidence":"GRA15/GRA24 double-KO parasites, CCR7 assays, macrophage adoptive transfer in mice, ATAC-seq, and NF-κB reporters","pmids":["39207098"],"confidence":"High","gaps":["How NF-κB and chromatin-accessibility inputs converge on Ccr7 not fully resolved","Relative contribution of each effector to dissemination not partitioned"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2024,"claim":"Uncovered a cell-type-specific immunosuppressive role, showing GRA15 in dendritic cells but not macrophages dampens humoral immunity and antigen-specific T cell responses.","evidence":"CD11c-Cre/GRA15 conditional knock-in mice with infection/OVA immunization, antibody titers, and flow cytometry","pmids":["39557359"],"confidence":"Medium","gaps":["Mechanism of DC-specific suppression not defined","Reconciliation with GRA15's pro-inflammatory activity in other contexts unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}]},{"year":2026,"claim":"Defined a chemokine-based dissemination mechanism whereby GRA15-driven NF-κB induces CCL5/RANTES in brain endothelium and DCs to promote infected-DC hypermotility, transmigration, and cerebral sequestration reversible by CCR5 antagonism.","evidence":"GRA15-KO parasites, NF-κB reporter, CCL5 ELISA, DC transmigration, and in vivo Maraviroc treatment with intravital microscopy","pmids":["41528135"],"confidence":"High","gaps":["Whether CCL5 acts autocrine on infected DCs or on endothelium primarily not fully separated","Long-term impact on cerebral parasite burden and pathology not quantified"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]},{"year":2025,"claim":"Showed GRA15 and TgWIP promote strain-dependent sequestration of parasitized DCs in cortical capillaries, enabling post-egress invasion of cortical neurons.","evidence":"GRA15-KO and TgWIP-KO parasites delivered intracarotid into mice with in vivo brain imaging and ICAM-1/CD18 blockade","pmids":["40229286"],"confidence":"Medium","gaps":["Relative contribution of GRA15 versus TgWIP to sequestration not partitioned","Molecular basis of strain-dependence not resolved"],"attribution":[{"species":"Toxoplasma gondii","strain":"type I (RH), type II (PRU/ME49), type III"}]},{"year":null,"claim":"How ER-localized GRA15 physically delivers TRAF-dependent signaling both to the cytoplasm/nucleus and to the PV membrane, and the structural basis of the GRA15-TRAF interaction, remain unresolved.","evidence":"No timeline discovery resolves the topology and structure that would unify GRA15's ER localization, cytoplasmic NF-κB activation, and PV-membrane TRAF recruitment","pmids":[],"confidence":"Low","gaps":["No structural model of the GRA15-TRAF complex","Mechanism coupling ER localization to PV-membrane TRAF recruitment unknown","Validated direct host binding partners beyond TRAFs limited"],"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["TRAF2","TRAF6","STING (VIA TRAF-DEPENDENT POLYUBIQUITINATION)","LUZP1 (Y2H, UNVALIDATED)","AW209491 (Y2H, UNVALIDATED)"],"other_free_text":["GRA15 is a polymorphic dense granule effector; NF-κB-activating function is predominantly encoded by the type II allele, and allelic polymorphism (including within type I strains RH vs GT1) governs strain-specific NF-κB output [#0, #5, #21].","GRA15 acts combinatorially with other effectors: antagonistically or cooperatively with ROP16 (STAT), and synergistically with GRA24 (p38 MAPK) and GRA28 (chromatin accessibility) in cytokine induction and CCR7-driven dissemination [#1, #4, #12, #20].","Downstream GRA15/NF-κB outputs include IL-1β, IL-12, IL-18, IL-6, CD40, ICAM-1, CCL5/RANTES, and CCR7, driving inflammation, dissemination, cerebral sequestration, and seizure susceptibility [#3, #6, #12, #13, #17, #19, #20, #24].","GRA15's NF-κB-activating function is conserved in Hammondia hammondi [#7]."]},"strain_conflicts":[{"aspect":"Requirement of GRA15 transmembrane architecture for NF-κB activation","claims":[{"attribution":[{"species":"Toxoplasma gondii","strain":"type II"}],"claim":"GRA15 uses its second transmembrane motif for ER localization and activates NF-κB via TRAF-binding sites","supporting_discovery_ids":[8,9]},{"attribution":[{"species":"Toxoplasma gondii","strain":"T.gHB1 (ToxoDB#10, type I)"}],"claim":"A structurally distinct GRA15 with only one transmembrane region and extended C-terminus still activates NF-κB, with residues 194–518 required","supporting_discovery_ids":[21]}]},{"aspect":"GRA15-mediated PV outcome across host species","claims":[{"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}],"claim":"In human primary fibroblasts GRA15 recruits TRAF2/TRAF6 and ubiquitin receptors leading to lysosomal degradation of the vacuole","supporting_discovery_ids":[11]},{"attribution":[{"species":"Toxoplasma gondii","strain":"type II (Prugniaud)"}],"claim":"In murine fibroblasts GRA15-mediated TRAF6 recruitment leads to immunity-related GTPase recruitment and vacuole destruction","supporting_discovery_ids":[11]}]}]},"prefetch_data":{},"corpus_meta":[{"pmid":"21199955","id":"PMC_21199955","title":"Strain-specific activation of the NF-kappaB pathway by GRA15, a novel Toxoplasma gondii dense granule protein.","date":"2011","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/21199955","citation_count":344,"is_preprint":false},{"pmid":"21669396","id":"PMC_21669396","title":"Toxoplasma polymorphic effectors determine macrophage polarization and intestinal inflammation.","date":"2011","source":"Cell host & 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isolates.","date":"2025","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/41036225","citation_count":1,"is_preprint":false},{"pmid":"32265514","id":"PMC_32265514","title":"The role of macrophage reprogramming induced by GRA15II, a polypeptide effector molecule of Toxoplasma gondii, in liver diseases in model mice.","date":"2020","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/32265514","citation_count":1,"is_preprint":false},{"pmid":"41528135","id":"PMC_41528135","title":"Toxoplasma effector GRA15-driven CCL5 secretion enhances brain parasite load through microvascular sequestration of phagocytes.","date":"2026","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/41528135","citation_count":0,"is_preprint":false},{"pmid":"41611885","id":"PMC_41611885","title":"Brain endothelial spheroids and cortical organoids reveal the impact of Toxoplasma gondii lineage and host-phagocyte-pathogen interactions on colonization.","date":"2026","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/41611885","citation_count":0,"is_preprint":false},{"pmid":"31704772","id":"PMC_31704772","title":"T. gondii inveSTING in a latent future.","date":"2019","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31704772","citation_count":0,"is_preprint":false},{"pmid":"42108599","id":"PMC_42108599","title":"The Potential Function of Toxoplasma gondii in Tumour Immunotherapy.","date":"2026","source":"Immunology","url":"https://pubmed.ncbi.nlm.nih.gov/42108599","citation_count":0,"is_preprint":false},{"pmid":"42322816","id":"PMC_42322816","title":"Dual transcriptomic analysis of Toxoplasma gondii infection in a human PBMC ex vivo model.","date":"2026","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/42322816","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":35383,"output_tokens":7677,"usd":0.110652,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":15621,"output_tokens":10292,"usd":0.167703,"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\": 2011,\n      \"finding\": \"GRA15 is a novel dense granule protein secreted by Toxoplasma gondii into the host cell upon invasion, and the type II allele is sufficient to activate NF-κB nuclear translocation and NF-κB-mediated transcription in host cells. A GRA15-deficient type II strain has a severe defect in NF-κB activation, and human cells expressing type II GRA15 activate NF-κB, demonstrating GRA15 alone is sufficient for this effect.\",\n      \"method\": \"Forward genetics (type II × type III cross), GRA15 knockout, stable expression of GRA15II in type I strain and human cells, NF-κB reporter assays, in vivo bioluminescent imaging\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (forward genetics, KO, heterologous expression), replicated across cell types, founding paper with rigorous controls\",\n      \"pmids\": [\"21199955\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (ME49/Prugniaud), type I (RH), type III\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"GRA15 (activating NF-κB) promotes classical (M1) macrophage activation by type II parasites, whereas ROP16 (activating STAT6) promotes alternative (M2) macrophage activation. GRA15 and ROP16 antagonistically regulate many of the same host genes, and their combined expression determines intestinal inflammation and parasite control in vivo.\",\n      \"method\": \"Macrophage polarization assays, genetic crosses, transgenic parasite expression, in vivo oral infection model\",\n      \"journal\": \"Cell host & microbe\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal approaches across two independent labs, epistasis confirmed in vivo\",\n      \"pmids\": [\"21669396\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"GRA15 (along with ROP16 and ROP18) is one of three parasitic factors that determine strain-specific accumulation of murine GBP1 on the parasitophorous vacuole (PV) in IFN-γ-activated cells; GRA15 contributes to GBP recruitment, linking it to the cell-autonomous immune response.\",\n      \"method\": \"Genetic crosses, transgenic parasite expression, immunofluorescence for mGBP1 localization on PV\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiments with transgenic parasites, single lab, multiple genetic tools\",\n      \"pmids\": [\"21931713\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GRA15 is responsible for IL-1β induction during T. gondii infection of human monocytes, acting upstream of caspase-1 and ASC (inflammasome components). A GRA15-knockout type II strain failed to induce IL-1β, and a type I strain expressing type II GRA15 gained the ability to induce IL-1β, establishing GRA15 as the parasite factor driving NF-κB-dependent IL-1β transcription.\",\n      \"method\": \"GRA15 knockout, stable transgenic expression of GRA15II in type I strain, shRNA knockdown of caspase-1 and ASC, IL-1β ELISA and transcript analysis\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal gain/loss-of-function with multiple orthogonal methods, caspase-1/ASC knockdown epistasis\",\n      \"pmids\": [\"23839215\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"ROP16 and GRA15 act in combination to promote host resistance to oral Toxoplasma infection; expression of STAT-activating ROP16 in type II strain promotes host resistance only when endogenous GRA15 is also present, and co-expression enhances parasite susceptibility in IFN-γ/TNF-stimulated macrophages.\",\n      \"method\": \"Transgenic parasite expression (type II + ROP16I), GRA15 genetic background, oral infection model, STAT3/6-deficient mice, macrophage killing assays\",\n      \"journal\": \"Infection and immunity\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with defined transgenic strains, multiple in vivo and in vitro readouts\",\n      \"pmids\": [\"23545295\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud), type I\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GRA15 polymorphisms between RH and GT1 type I strains account for differential NF-κB activation between these strains. Furthermore, RH (but not other type I strains) recruits phosphorylated IκBα to the parasitophorous vacuole membrane in a manner partially dependent on GRA2.\",\n      \"method\": \"Whole genome sequencing (SNP identification), host transcriptional profiling, NF-κB activation assays, immunofluorescence for p-IκBα\",\n      \"journal\": \"BMC genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — comparative genomics plus functional validation, single lab\",\n      \"pmids\": [\"23837824\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH (type I), GT1 (type I)\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Type II GRA15 induces expression of CD40 on infected macrophages in an NF-κB-dependent manner. Stable expression of HA-tagged GRA15II in THP-1 cells upregulated CD40 in the absence of infection. CD40 induction was mapped by forward genetics to a chromosomal region containing GRA15, and CD40L engagement of GRA15II-induced CD40 amplified the IL-12 response.\",\n      \"method\": \"Forward genetics (type II × type III cross), stable GRA15II expression in type I parasites and THP-1 cells, NF-κB inhibitor treatment, CD40 flow cytometry, IL-12 ELISA\",\n      \"journal\": \"Infection and immunity\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — forward genetics plus heterologous expression, NF-κB inhibitor epistasis, multiple orthogonal methods\",\n      \"pmids\": [\"25024369\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"GRA15 and ROP16 from Hammondia hammondi are functionally conserved; HhGRA15 modulates host NF-κB pathway when expressed heterologously in T. gondii, confirming that GRA15's NF-κB-activating function is conserved across closely related apicomplexans.\",\n      \"method\": \"Heterologous expression of HhGRA15 in T. gondii, NF-κB reporter assays\",\n      \"journal\": \"Eukaryotic cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional heterologous expression assay, single lab\",\n      \"pmids\": [\"25280815\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Hammondia hammondi\", \"strain\": \"\"}, {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GRA15 activates the NF-κB pathway by interacting with TNF receptor-associated factors (TRAFs). Multiple TRAF-binding sites were identified in the GRA15 amino acid sequence; deletion of these sites greatly reduces NF-κB activation. TRAF2 knockout cells display impaired GRA15-mediated NF-κB activation, establishing TRAF proteins as the molecular link between GRA15 and NF-κB.\",\n      \"method\": \"Co-immunoprecipitation (GRA15–TRAF interaction), TRAF-binding site deletion mutagenesis, TRAF2 knockout cells, NF-κB reporter assays\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — mutagenesis of binding sites combined with KO cell lines and reporter assays, multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"31311877\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GRA15 is secreted into the host cell cytoplasm and localizes to the endoplasmic reticulum via its second transmembrane motif. GRA15 promotes STING polyubiquitination at Lys-337 and STING oligomerization in a TRAF-dependent manner, thereby activating STING and innate immune signaling (type I IFNs). GRA15-deficient T. gondii failed to activate STING-dependent responses and was more virulent in wild-type but not Stinggt/gt mice.\",\n      \"method\": \"GRA15 subcellular fractionation/localization (ER), transmembrane domain mutants, STING polyubiquitination assay, STING oligomerization assay, GRA15-KO parasites, Stinggt/gt mice infection\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (localization, biochemical ubiquitination assay, KO parasites, genetic host model), single lab but comprehensive\",\n      \"pmids\": [\"31416833\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GRA15-dependent NF-κB activation induces NLRP3 inflammasome-dependent IL-1β production from infected monocytes; IL-1β in turn combines with IFN-γ to strongly stimulate iNOS in hepatocytes, which reduces IDO1 expression, a key IFN-γ-inducible anti-Toxoplasma effector. Thus GRA15 indirectly suppresses IFN-γ-induced IDO1-mediated cell-autonomous immunity in humans by upregulating iNOS.\",\n      \"method\": \"GRA15-KO parasites, monocyte-hepatocyte co-culture, iNOS inhibition, NLRP3 inflammasome inhibition, IDO1 expression analysis\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — GRA15-KO with defined cellular epistasis across two cell types, inhibitor validation, multiple orthogonal approaches\",\n      \"pmids\": [\"30301855\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GRA15 mediates recruitment of ubiquitin ligases TRAF2 and TRAF6 to the parasitophorous vacuole membrane in human primary fibroblasts, which enhances recruitment of ubiquitin receptors (p62/NDP52) and ubiquitin-like molecules (LC3B, GABARAP), ultimately leading to lysosomal degradation of the vacuole. In murine fibroblasts, GRA15-mediated TRAF6 recruitment leads to recruitment of immunity-related GTPases and vacuole destruction.\",\n      \"method\": \"GRA15-KO parasites, immunofluorescence for TRAF2/TRAF6/p62/NDP52/LC3B/GABARAP at PV, lysosomal degradation assays, murine vs. human fibroblast comparison\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — GRA15-KO with mechanistic follow-up across two species' cells, multiple markers, defined pathway\",\n      \"pmids\": [\"32293748\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GRA15 and GRA24 synergistically shape innate immune responses in Tlr11-/- mice and human macrophages; GRA15 is the predominant effector for IL-12, IL-18, and IL-1β secretion in these contexts. GRA15/GRA24-mediated cytokine induction activates IFN-γ secretion by PBMCs, which controls Toxoplasma proliferation.\",\n      \"method\": \"GRA15 and GRA24 single/double KO parasites, Tlr11-/- mice infection, human macrophage infection, cytokine ELISAs, PBMC IFN-γ assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with epistasis, multiple host models (KO mice, human macrophages), multiple cytokine readouts\",\n      \"pmids\": [\"32453782\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GRA15, GRA7, and GRA14 are all involved in NF-κB activation in type II T. gondii; GRA15 is essential for NF-κB activation (nuclear translocation of RelA, phosphorylation of IκBα), while GRA7 and GRA14 only partially contribute. Deletion of GRA15 in Pru strain reduces IL-6 and shows predominantly downregulated NF-κB-mediated gene expression.\",\n      \"method\": \"Luciferase NF-κB reporter screen, GRA15/GRA7/GRA14 KO in Pru strain, immunofluorescence for RelA nuclear translocation, IκBα phosphorylation western blot, RNA-seq\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO parasites with multiple biochemical and transcriptomic readouts, luciferase screen for mechanism\",\n      \"pmids\": [\"32849602\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Yeast two-hybrid screening identified mouse Luzp1 and AW209491 as host binding proteins that interact with GRA15II.\",\n      \"method\": \"Yeast two-hybrid screen with mouse cDNA library using GRA15II as bait, western blot validation of bait expression\",\n      \"journal\": \"Parasites & vectors\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single yeast two-hybrid screen, no co-IP validation or functional follow-up in the abstract\",\n      \"pmids\": [\"28049510\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"PRU (type II)\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"GRA15 and ROP16 differentially modulate specific aspects of IFN-γ signaling: GRA15 activates NF-κB/IRF1 to modulate expression of a subset of IFN-γ-responsive genes, while ROP16 activates STAT3/6 to modulate a different subset. However, all three clonal lineages equally inhibit STAT1 transcriptional activity, indicating STAT1 inhibition is independent of GRA15 or ROP16.\",\n      \"method\": \"Stable STAT1-specific reporter cell line, transcriptional profiling, GRA15/ROP16 allele comparisons across clonal types\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assays with genetic comparisons, single lab, two orthogonal readouts\",\n      \"pmids\": [\"23240025\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"GRA15-dependent suppression of IFN-γ-induced IDO1 anti-parasite response operates in human neuronal cell lines and primary human neurons, in addition to hepatocytes and monocytes; the mechanism involves GRA15-induced IL-1β production leading to iNOS-dependent IDO1 suppression in brain cells.\",\n      \"method\": \"Type II T. gondii-infected THP-1 monocytes co-cultured with neuronal cell lines/primary neurons, GRA15-KO comparison, IDO1 expression assays, IL-1β and iNOS measurements\",\n      \"journal\": \"Frontiers in cellular and infection microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — GRA15-KO epistasis in co-culture system, single lab, consistent with prior mechanistic framework\",\n      \"pmids\": [\"31119110\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"GRA15 is important for increased expression of IL-1β and other IL-1 pathway host genes in the brains of toxoplasmic encephalitic mice; QTL mapping identified GRA15 as the Toxoplasma gene in a locus correlating with seizure onset. Inhibiting IL-1 receptor signaling reduced seizure severity.\",\n      \"method\": \"QTL mapping, GRA15-KO parasites, mouse brain gene expression analysis, IL-1 receptor inhibitor treatment, seizure scoring\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — QTL mapping plus GRA15-KO functional validation in vivo, single lab\",\n      \"pmids\": [\"34154412\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"GRA15 is required for inflammasome-induced IL-1β release during T. gondii infection; knocking out GRA15 in Δmag1 parasites completely inhibited IL-1β release, indicating GRA15 is the primary driver of IL-1β induction (which MAG1 counteracts). This confirms GRA15's role in inflammasome activation during infection.\",\n      \"method\": \"Δmag1, Δgra15, and Δmag1/Δgra15 double-KO parasites, BMDM infection, IL-1β ELISA, heterologous MAG1 complementation\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — double KO epistasis with complementation, single lab, clean genetic dissection\",\n      \"pmids\": [\"34006649\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GRA15 induces ICAM-1 expression on infected dendritic cells via NF-κB signaling, which promotes enhanced cell adhesion and trans-endothelial migration (TEM). GRA15 deletion or Icam-1 gene silencing reduced TEM, while TgWIP (separately) also facilitates TEM through regulation of host actin dynamics.\",\n      \"method\": \"GRA15-KO parasites, siRNA silencing of Icam-1 in primary DCs, TEM assay across polarized brain endothelial monolayers, immunofluorescence for ICAM-1\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — GRA15-KO and gene silencing with functional TEM readout, single lab\",\n      \"pmids\": [\"35990682\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GRA15 promotes CCR7-mediated macrophage chemotaxis by acting on the NF-κB signaling pathway. GRA15 and GRA24 (acting on NF-κB and p38 MAPK, respectively) together with GRA28-boosted chromatin accessibility at the Ccr7 gene locus drive parasite dissemination in vivo. In vivo, macrophages infected with a GRA15/GRA24 double mutant had reduced migration to secondary organs compared to WT-infected macrophages.\",\n      \"method\": \"GRA15/GRA24 double-KO parasites, CCR7 expression assays, adoptive transfer of macrophages in mice, chromatin accessibility assay (ATAC-seq), NF-κB reporter assays\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — double KO with in vivo adoptive transfer, ATAC-seq, and signaling pathway dissection; multiple orthogonal methods\",\n      \"pmids\": [\"39207098\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"A newly isolated type 1 strain (T.gHB1/ToxoDB#10) carries a structurally distinct GRA15 with only one transmembrane region and an extended C-terminal region. This GRA15 activates NF-κB through IκBα phosphorylation and p65 nuclear translocation; deletion mapping showed that residues 194–518 of T.gHB1 GRA15 are required for NF-κB activation.\",\n      \"method\": \"NF-κB reporter assays, western blot for IκBα phosphorylation and p65 nuclear translocation, truncation/deletion mutagenesis of GRA15\",\n      \"journal\": \"Parasites & vectors\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutagenesis with functional reporter assays, single lab, single strain\",\n      \"pmids\": [\"36175964\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"T.gHB1 (ToxoDB#10, type I)\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GRA15II expressed in choriocarcinoma JEG-3 cells induces endoplasmic reticulum stress (ERS) via IRE1α/JNK pathway and subsequently causes apoptosis; inhibition of IRE1α or JNK reduced GRA15II-induced apoptosis and decreased TRAF2 and ASK1 activation.\",\n      \"method\": \"Transfection of pEGFP-GRA15II into JEG-3 cells, IRE1α inhibitor (4μ8C) and JNK inhibitor (SP6000125), western blot for apoptosis/ERS markers, flow cytometry\",\n      \"journal\": \"Parasites & vectors\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — pharmacological inhibitors with multiple apoptosis/ERS markers, single lab, heterologous expression system\",\n      \"pmids\": [\"29665822\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (PRU)\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GRA15 expression in dendritic cells (but not macrophages) suppresses T cell-mediated humoral immunity; conditional knock-in mice expressing GRA15 specifically in CD11c+ dendritic cells (CD11c-Cre/GRA15cKI) produced lower anti-T. gondii and anti-OVA antibody titers and had reduced numbers of antigen-specific T cells.\",\n      \"method\": \"Conditional knock-in mice (CD11c-Cre/GRA15cKI and macrophage-specific), infection and OVA immunization, antibody titer measurements, flow cytometry for plasma cells and T cells\",\n      \"journal\": \"Parasitology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific conditional knock-in model with functional immune readouts, single lab\",\n      \"pmids\": [\"39557359\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"GRA15 drives transcriptional and secretory upregulation of CCL5/RANTES in primary brain endothelial cells and dendritic cells through NF-κB signaling. CCL5 induces hypermotility and chemotaxis of infected DCs and enhances their transmigration across endothelial monolayers. In vivo, GRA15-driven CCL5 increases sequestration of infected DCs in brain microvasculature and cerebral parasite loads; CCR5 antagonist (Maraviroc) reversed sequestration.\",\n      \"method\": \"GRA15-KO parasites, NF-κB reporter assay, CCL5 ELISA, DC transmigration assay, in vivo mouse infection with Maraviroc treatment, intravital microscopy of cerebral microvasculature\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — GRA15-KO with in vitro mechanistic dissection, in vivo pharmacological validation, multiple orthogonal readouts in one study\",\n      \"pmids\": [\"41528135\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"GRA15 and TgWIP effectors increase the sequestration of parasitized dendritic cells in cortical capillaries and cerebral parasite loads in a strain-dependent manner following intracarotid delivery; post-replicative egress from sequestered DCs enables rapid parasite localization in cortical neurons.\",\n      \"method\": \"GRA15-KO and TgWIP-KO parasites, intracarotid arterial delivery into mice, in vivo brain imaging, ICAM-1/CD18 blocking antibody treatment\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO parasites with in vivo intravascular delivery model, single lab\",\n      \"pmids\": [\"40229286\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I (RH), type II (PRU/ME49), type III\"}]\n    }\n  ],\n  \"current_model\": \"GRA15 is a polymorphic dense granule protein secreted by Toxoplasma gondii into the host cell cytoplasm, where it localizes to the endoplasmic reticulum via its second transmembrane domain and activates the NF-κB pathway by directly interacting with TRAF adaptor proteins (including TRAF2 and TRAF6) through defined TRAF-binding sites; this drives classical macrophage activation, IL-1β/IL-12/IL-18 production, STING polyubiquitination and activation, ICAM-1 and CCL5 induction in dendritic cells and brain endothelium, GBP/IRG recruitment to the parasitophorous vacuole, and CCR7-mediated macrophage chemotaxis—collectively regulating parasite dissemination, cell-autonomous immunity, neuroinflammation, and seizure susceptibility in a strain-specific (predominantly type II allele) manner.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GRA15 is a polymorphic dense granule protein secreted by Toxoplasma gondii into the host cell upon invasion, where it functions as the parasite's principal activator of the host NF-\\u03baB pathway and thereby reprograms innate immunity, inflammation, and parasite dissemination [#0]. Secreted GRA15 traffics to the host endoplasmic reticulum via its second transmembrane motif and drives NF-\\u03baB activation\\u2014I\\u03baB\\u03b1 phosphorylation, RelA/p65 nuclear translocation, and NF-\\u03baB-dependent transcription\\u2014by directly binding TNF-receptor-associated factors (TRAFs) through defined TRAF-binding sites, with TRAF2 required for full activity [#8, #9, #13]. Through this NF-\\u03baB axis GRA15 promotes classical (M1) macrophage activation in antagonism with the STAT-activating effector ROP16 [#1], and induces a broad inflammatory program including IL-1\\u03b2, IL-12, IL-18, IL-6, and CD40 [#3, #6, #12]. GRA15-driven, NLRP3/caspase-1/ASC-dependent IL-1\\u03b2 production couples the parasite to inflammasome signaling and, via IL-1\\u03b2\\u2013iNOS induction, indirectly suppresses IFN-\\u03b3-induced IDO1 anti-parasite defense in hepatocytes and neurons [#3, #10, #16, #18]. At the parasitophorous vacuole, GRA15 recruits TRAF2 and TRAF6 and downstream ubiquitin receptors and ubiquitin-like molecules to target the vacuole for lysosomal degradation and immunity-related GTPase attack, and promotes STING polyubiquitination and oligomerization to activate type I IFN responses [#9, #11]. GRA15 also induces ICAM-1, CCL5/RANTES, and CCR7 in dendritic cells and brain endothelium to enhance infected-cell chemotaxis, transendothelial migration, and cerebral sequestration, and its IL-1-driven neuroinflammation increases seizure susceptibility [#17, #19, #20, #24]. These activities are predominantly encoded by the type II allele, and allelic polymorphism accounts for strain-specific NF-\\u03baB output [#0, #5].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Established that a secreted parasite dense granule protein\\u2014not merely host recognition\\u2014is sufficient to activate host NF-\\u03baB, identifying GRA15 as the strain-specific driver of this response.\",\n      \"evidence\": \"Forward genetics from a type II \\u00d7 type III cross, GRA15 knockout, and heterologous GRA15II expression in a type I strain and human cells with NF-\\u03baB reporter assays\",\n      \"pmids\": [\"21199955\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism linking GRA15 to NF-\\u03baB not yet defined\", \"Subcellular localization of GRA15 in the host cell not established\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (ME49/Prugniaud), type I (RH), type III\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Placed GRA15 within a broader immunomodulatory logic by showing it drives M1 macrophage polarization in antagonism with ROP16-driven M2 polarization, jointly determining intestinal inflammation and parasite control.\",\n      \"evidence\": \"Macrophage polarization assays, genetic crosses, transgenic expression, and in vivo oral infection\",\n      \"pmids\": [\"21669396\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct GRA15 effector partners not identified\", \"How opposing NF-\\u03baB and STAT6 signals are integrated on shared genes unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Linked GRA15 to cell-autonomous immunity by showing it contributes to strain-specific recruitment of murine GBP1 to the parasitophorous vacuole.\",\n      \"evidence\": \"Genetic crosses, transgenic parasites, and immunofluorescence for mGBP1 at the PV\",\n      \"pmids\": [\"21931713\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting GRA15/NF-\\u03baB to GBP recruitment not defined\", \"Relative contribution versus ROP18/ROP16 unclear\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Resolved which arms of IFN-\\u03b3 signaling GRA15 controls, showing it modulates an NF-\\u03baB/IRF1-dependent gene subset while STAT1 inhibition occurs independently of GRA15.\",\n      \"evidence\": \"STAT1 reporter cell line and transcriptional profiling across clonal lineages with GRA15/ROP16 allele comparisons\",\n      \"pmids\": [\"23240025\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The GRA15-independent STAT1 inhibitor not identified\", \"Direct IRF1 engagement not mechanistically tested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified GRA15 as the parasite factor driving inflammasome-associated IL-1\\u03b2, acting upstream of caspase-1/ASC via NF-\\u03baB-dependent transcription in human monocytes.\",\n      \"evidence\": \"Reciprocal GRA15 knockout and gain-of-function expression with caspase-1/ASC knockdown and IL-1\\u03b2 measurement\",\n      \"pmids\": [\"23839215\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which inflammasome sensor is engaged not defined here\", \"Direct GRA15 interactors upstream of NF-\\u03baB not identified\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Demonstrated GRA15 polymorphism explains differential NF-\\u03baB output even within type I strains, and that RH additionally recruits phospho-I\\u03baB\\u03b1 to the PV membrane partly via GRA2.\",\n      \"evidence\": \"Whole-genome SNP identification, host transcriptional profiling, NF-\\u03baB assays, and p-I\\u03baB\\u03b1 immunofluorescence\",\n      \"pmids\": [\"23837824\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific GRA15 residues responsible for RH/GT1 divergence not mapped\", \"Relationship between PV-localized p-I\\u03baB\\u03b1 and cytoplasmic GRA15 function unclear\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH (type I), GT1 (type I)\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Showed GRA15 and ROP16 cooperate genetically to promote host resistance to oral infection, refining the two effectors from purely antagonistic to context-dependent partners.\",\n      \"evidence\": \"Transgenic type II + ROP16I parasites on defined GRA15 backgrounds, oral infection, STAT-deficient mice, and macrophage killing assays\",\n      \"pmids\": [\"23545295\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of GRA15/ROP16 cooperativity not defined\", \"Effector-specific gene targets governing resistance not enumerated\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud), type I\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Extended the GRA15 NF-\\u03baB program to costimulatory signaling by mapping NF-\\u03baB-dependent CD40 induction to GRA15, amplifying IL-12 responses.\",\n      \"evidence\": \"Forward genetics, heterologous GRA15II expression in THP-1, NF-\\u03baB inhibitor epistasis, and CD40/IL-12 readouts\",\n      \"pmids\": [\"25024369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CD40 induction is direct or via secondary cytokines untested\", \"In vivo relevance of CD40 amplification not addressed\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrated evolutionary conservation of GRA15's NF-\\u03baB-activating function in the sister species Hammondia hammondi.\",\n      \"evidence\": \"Heterologous expression of HhGRA15 in T. gondii with NF-\\u03baB reporter assays\",\n      \"pmids\": [\"25280815\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Conservation of downstream partners in H. hammondi not tested\", \"Native H. hammondi host response not examined\"],\n      \"attribution\": [{\"species\": \"Hammondia hammondi\", \"strain\": \"\"}, {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"First attempt to identify direct host binding partners of GRA15, nominating mouse Luzp1 and AW209491.\",\n      \"evidence\": \"Yeast two-hybrid screen using GRA15II as bait against a mouse cDNA library\",\n      \"pmids\": [\"28049510\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No co-IP or reciprocal validation of the interactions\", \"No functional link between these partners and NF-\\u03baB established\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"PRU (type II)\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected GRA15-driven IL-1\\u03b2 to suppression of host defense by showing IL-1\\u03b2 plus IFN-\\u03b3 upregulates iNOS, which reduces the anti-Toxoplasma effector IDO1.\",\n      \"evidence\": \"GRA15-KO parasites in monocyte-hepatocyte co-culture with NLRP3 and iNOS inhibition and IDO1 readouts\",\n      \"pmids\": [\"30301855\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of iNOS-mediated IDO1 suppression not fully defined\", \"Systemic in vivo consequence of IDO1 suppression not tested here\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Showed heterologously expressed GRA15II can trigger ER stress via IRE1\\u03b1/JNK and TRAF2/ASK1 activation, linking GRA15 to apoptotic signaling in placental cells.\",\n      \"evidence\": \"Transfection of GRA15II into JEG-3 cells with IRE1\\u03b1 and JNK inhibitors and apoptosis/ER stress marker western blots\",\n      \"pmids\": [\"29665822\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Heterologous overexpression may not reflect secreted GRA15 during infection\", \"Relationship to NF-\\u03baB activation and TRAF binding not directly reconciled\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (PRU)\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined the molecular mechanism of GRA15-mediated NF-\\u03baB activation by identifying TRAF-binding sites in GRA15 and showing TRAF2 is required.\",\n      \"evidence\": \"Co-immunoprecipitation of GRA15\\u2013TRAF, TRAF-binding site deletion mutagenesis, TRAF2 knockout cells, and NF-\\u03baB reporter assays\",\n      \"pmids\": [\"31311877\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and structure of the GRA15-TRAF complex not resolved\", \"Which additional TRAFs act redundantly not fully mapped\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Localized GRA15 to the host ER via its second transmembrane motif and showed it promotes TRAF-dependent STING polyubiquitination and oligomerization to activate type I IFN.\",\n      \"evidence\": \"Subcellular fractionation, transmembrane domain mutants, STING ubiquitination/oligomerization assays, GRA15-KO parasites, and Stinggt/gt mice\",\n      \"pmids\": [\"31416833\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct versus indirect action of GRA15 on the STING ubiquitination machinery unresolved\", \"Identity of the ubiquitin ligase modifying STING Lys-337 not defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Generalized the GRA15\\u2013IL-1\\u03b2\\u2013iNOS\\u2013IDO1 axis to brain cells, showing GRA15 suppresses IFN-\\u03b3-induced IDO1 in human neurons.\",\n      \"evidence\": \"GRA15-KO comparison in monocyte-neuron co-cultures with IL-1\\u03b2, iNOS, and IDO1 measurements\",\n      \"pmids\": [\"31119110\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Neuron-intrinsic versus monocyte-derived signaling not fully separated\", \"In vivo brain relevance not tested in this study\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Established GRA15 as the recruiter of TRAF2/TRAF6 to the PV membrane, seeding ubiquitin receptors and ubiquitin-like conjugates that drive lysosomal and IRG-mediated vacuole destruction, with species-specific outcomes.\",\n      \"evidence\": \"GRA15-KO parasites with immunofluorescence for TRAF2/TRAF6/p62/NDP52/LC3B/GABARAP and lysosomal degradation assays in human versus murine fibroblasts\",\n      \"pmids\": [\"32293748\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ER-localized GRA15 delivers TRAFs to the PV membrane unclear\", \"Determinants of the divergent human versus mouse outcomes not fully defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed GRA15 is the predominant effector for IL-12/IL-18/IL-1\\u03b2 secretion and, with GRA24, drives IFN-\\u03b3 production that controls parasite proliferation.\",\n      \"evidence\": \"GRA15/GRA24 single and double KO parasites, Tlr11-/- mice, human macrophages, and PBMC IFN-\\u03b3 assays\",\n      \"pmids\": [\"32453782\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of GRA15/GRA24 synergy not defined\", \"Contribution of individual cytokines to IFN-\\u03b3 induction not dissected\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Confirmed GRA15 as the essential NF-\\u03baB activator among dense granule proteins, with GRA7 and GRA14 only partially contributing, and mapped its transcriptional footprint.\",\n      \"evidence\": \"Luciferase NF-\\u03baB reporter screen, GRA15/GRA7/GRA14 KO in Pru, RelA translocation and I\\u03baB\\u03b1 phosphorylation, and RNA-seq\",\n      \"pmids\": [\"32849602\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How GRA7/GRA14 contribute mechanistically not defined\", \"Full set of NF-\\u03baB target genes governing outcome not prioritized\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected GRA15 to neuropathology by mapping it as the parasite gene driving brain IL-1 pathway induction and seizure susceptibility.\",\n      \"evidence\": \"QTL mapping, GRA15-KO parasites, brain gene expression, and IL-1 receptor inhibition with seizure scoring\",\n      \"pmids\": [\"34154412\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cell types responsible for brain IL-1\\u03b2 induction not fully defined\", \"Direct causal chain from GRA15 to seizure circuitry unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Genetically dissected the inflammasome axis, showing GRA15 is the primary driver of IL-1\\u03b2 release that MAG1 counteracts.\",\n      \"evidence\": \"\\u0394mag1, \\u0394gra15, and double-KO parasites with BMDM IL-1\\u03b2 ELISA and MAG1 complementation\",\n      \"pmids\": [\"34006649\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which MAG1 antagonizes GRA15-driven IL-1\\u03b2 not defined\", \"Whether antagonism occurs at transcription or inflammasome assembly unclear\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Showed GRA15-driven NF-\\u03baB induces ICAM-1 on infected dendritic cells to promote adhesion and transendothelial migration, implicating GRA15 in parasite dissemination.\",\n      \"evidence\": \"GRA15-KO parasites, Icam-1 siRNA silencing in primary DCs, and transendothelial migration assays across brain endothelium\",\n      \"pmids\": [\"35990682\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Contribution of ICAM-1 versus other NF-\\u03baB targets to migration not quantified\", \"In vivo dissemination consequence tested separately\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Revealed GRA15 structural diversity by characterizing a type I strain with a single-transmembrane, C-terminally extended GRA15 that still activates NF-\\u03baB, mapping the required region to residues 194\\u2013518.\",\n      \"evidence\": \"NF-\\u03baB reporter assays, I\\u03baB\\u03b1 phosphorylation and p65 translocation western blots, and truncation mutagenesis of T.gHB1 GRA15\",\n      \"pmids\": [\"36175964\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the single-TM variant still localizes to ER not tested\", \"TRAF-binding requirement of this variant not directly examined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"T.gHB1 (ToxoDB#10, type I)\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Established GRA15 as a driver of infected-cell motility for dissemination by inducing CCR7-mediated macrophage chemotaxis via NF-\\u03baB, cooperating with GRA24 and GRA28.\",\n      \"evidence\": \"GRA15/GRA24 double-KO parasites, CCR7 assays, macrophage adoptive transfer in mice, ATAC-seq, and NF-\\u03baB reporters\",\n      \"pmids\": [\"39207098\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How NF-\\u03baB and chromatin-accessibility inputs converge on Ccr7 not fully resolved\", \"Relative contribution of each effector to dissemination not partitioned\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Uncovered a cell-type-specific immunosuppressive role, showing GRA15 in dendritic cells but not macrophages dampens humoral immunity and antigen-specific T cell responses.\",\n      \"evidence\": \"CD11c-Cre/GRA15 conditional knock-in mice with infection/OVA immunization, antibody titers, and flow cytometry\",\n      \"pmids\": [\"39557359\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of DC-specific suppression not defined\", \"Reconciliation with GRA15's pro-inflammatory activity in other contexts unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defined a chemokine-based dissemination mechanism whereby GRA15-driven NF-\\u03baB induces CCL5/RANTES in brain endothelium and DCs to promote infected-DC hypermotility, transmigration, and cerebral sequestration reversible by CCR5 antagonism.\",\n      \"evidence\": \"GRA15-KO parasites, NF-\\u03baB reporter, CCL5 ELISA, DC transmigration, and in vivo Maraviroc treatment with intravital microscopy\",\n      \"pmids\": [\"41528135\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether CCL5 acts autocrine on infected DCs or on endothelium primarily not fully separated\", \"Long-term impact on cerebral parasite burden and pathology not quantified\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed GRA15 and TgWIP promote strain-dependent sequestration of parasitized DCs in cortical capillaries, enabling post-egress invasion of cortical neurons.\",\n      \"evidence\": \"GRA15-KO and TgWIP-KO parasites delivered intracarotid into mice with in vivo brain imaging and ICAM-1/CD18 blockade\",\n      \"pmids\": [\"40229286\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of GRA15 versus TgWIP to sequestration not partitioned\", \"Molecular basis of strain-dependence not resolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I (RH), type II (PRU/ME49), type III\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How ER-localized GRA15 physically delivers TRAF-dependent signaling both to the cytoplasm/nucleus and to the PV membrane, and the structural basis of the GRA15-TRAF interaction, remain unresolved.\",\n      \"evidence\": \"No timeline discovery resolves the topology and structure that would unify GRA15's ER localization, cytoplasmic NF-\\u03baB activation, and PV-membrane TRAF recruitment\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of the GRA15-TRAF complex\", \"Mechanism coupling ER localization to PV-membrane TRAF recruitment unknown\", \"Validated direct host binding partners beyond TRAFs limited\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0051059\", \"supporting_discovery_ids\": [8, 11], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]},\n      {\"term_id\": \"GO:0031625\", \"supporting_discovery_ids\": [8, 11], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [9], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]},\n      {\"term_id\": \"GO:0005938\", \"supporting_discovery_ids\": [11], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0038061\", \"supporting_discovery_ids\": [0, 8, 13], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]},\n      {\"term_id\": \"GO:0032731\", \"supporting_discovery_ids\": [3, 10, 18], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]},\n      {\"term_id\": \"GO:0002827\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type I, type II, type III\"}]},\n      {\"term_id\": \"GO:0002218\", \"supporting_discovery_ids\": [9], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}]},\n      {\"term_id\": \"GO:0060333\", \"supporting_discovery_ids\": [10, 15, 16], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TRAF2\", \"TRAF6\", \"STING (via TRAF-dependent polyubiquitination)\", \"Luzp1 (Y2H, unvalidated)\", \"AW209491 (Y2H, unvalidated)\"],\n    \"other_free_text\": [\n      \"GRA15 is a polymorphic dense granule effector; NF-\\u03baB-activating function is predominantly encoded by the type II allele, and allelic polymorphism (including within type I strains RH vs GT1) governs strain-specific NF-\\u03baB output [#0, #5, #21].\",\n      \"GRA15 acts combinatorially with other effectors: antagonistically or cooperatively with ROP16 (STAT), and synergistically with GRA24 (p38 MAPK) and GRA28 (chromatin accessibility) in cytokine induction and CCR7-driven dissemination [#1, #4, #12, #20].\",\n      \"Downstream GRA15/NF-\\u03baB outputs include IL-1\\u03b2, IL-12, IL-18, IL-6, CD40, ICAM-1, CCL5/RANTES, and CCR7, driving inflammation, dissemination, cerebral sequestration, and seizure susceptibility [#3, #6, #12, #13, #17, #19, #20, #24].\",\n      \"GRA15's NF-\\u03baB-activating function is conserved in Hammondia hammondi [#7].\"\n    ]\n  },\n  \"strain_conflicts\": [\n    {\n      \"aspect\": \"Requirement of GRA15 transmembrane architecture for NF-\\u03baB activation\",\n      \"claims\": [\n        {\"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II\"}], \"claim\": \"GRA15 uses its second transmembrane motif for ER localization and activates NF-\\u03baB via TRAF-binding sites\", \"supporting_discovery_ids\": [8, 9]},\n        {\"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"T.gHB1 (ToxoDB#10, type I)\"}], \"claim\": \"A structurally distinct GRA15 with only one transmembrane region and extended C-terminus still activates NF-\\u03baB, with residues 194\\u2013518 required\", \"supporting_discovery_ids\": [21]}\n      ]\n    },\n    {\n      \"aspect\": \"GRA15-mediated PV outcome across host species\",\n      \"claims\": [\n        {\"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}], \"claim\": \"In human primary fibroblasts GRA15 recruits TRAF2/TRAF6 and ubiquitin receptors leading to lysosomal degradation of the vacuole\", \"supporting_discovery_ids\": [11]},\n        {\"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"type II (Prugniaud)\"}], \"claim\": \"In murine fibroblasts GRA15-mediated TRAF6 recruitment leads to immunity-related GTPase recruitment and vacuole destruction\", \"supporting_discovery_ids\": [11]}\n      ]\n    }\n  ]\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_275470","name":"GRA15","product":"dense granule protein GRA15","uniprot_acc":"A0A125YGQ9","chromosome":"TGME49_chrX","start_pos":7286296},{"strain":"GT1","gene_id":"TGGT1_275470","name":null,"product":"dense granule protein GRA15","uniprot_acc":null,"chromosome":"TGGT1_chrX","start_pos":7172933},{"strain":"VEG","gene_id":"TGVEG_275470","name":null,"product":"dense granule protein GRA15","uniprot_acc":"V4Z7A0","chromosome":"TGVEG_chrX","start_pos":7208354}]}