{"gene":"TG_260820","gene_symbol":"ISP1","run_date":"2026-09-10T21:09:19","timeline":{"discoveries":[{"year":2010,"finding":"ISP1 localizes to the apical cap sub-compartment of the Toxoplasma IMC, dependent on N-terminal residues predicted for coordinated myristoylation and palmitoylation; the N-terminal region is necessary and sufficient for apical cap targeting.","method":"Fluorescence microscopy, N-terminal truncation/mutation analyses, live imaging","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct localization experiments with deletion analyses replicated across multiple constructs in a single rigorous study, functional consequence (mislocalization of ISP2/3) demonstrated","pmids":["20844581"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"finding":"ISP1 acts as a 'gate-keeper' that excludes ISP2 and ISP3 from the apical cap: disruption of ISP1 causes dramatic relocalization of ISP2 and ISP3 to the apical cap, revealing a hierarchical targeting mechanism. The C-terminal region (beyond the N-terminal targeting domain) is required for this exclusion function.","method":"Gene knockout of ISP1 followed by fluorescence microscopy of ISP2/ISP3 localization; deletion analyses of C-terminal region","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic loss-of-function with defined molecular phenotype (relocalization of two paralogues), domain mapping with multiple deletion constructs, single rigorous study with multiple orthogonal methods","pmids":["20844581"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"finding":"Crystal structures of TgISP1 and TgISP3 were solved to 2.10 Å and 2.32 Å resolution, respectively, revealing that both proteins adopt a pleckstrin homology (PH) fold. Biochemical assays showed no phospholipid binding activity despite the PH fold; conserved surface residues map to the putative ligand-binding site, suggesting functional repurposing of this site for protein-protein interactions rather than lipid binding.","method":"X-ray crystallography (2.10 Å for ISP1, 2.32 Å for ISP3), phospholipid binding assays, conservation mapping","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure determination at high resolution combined with biochemical binding assays (negative phospholipid result) and conservation analysis, multiple orthogonal methods in one study","pmids":["24675080"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2012,"finding":"Preliminary X-ray diffraction data for N-terminally truncated TgISP1 were obtained, with two crystal forms (space groups P4(1)32 or P4(3)32, and P2(1)2(1)2(1)) diffracting to 2.05 and 2.1 Å resolution, establishing that a soluble, structured domain exists in ISP1 amenable to structural characterization.","method":"Protein purification from E. coli, crystallization, X-ray diffraction analysis","journal":"Acta crystallographica. Section F, Structural biology and crystallization communications","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — crystallographic data collection established crystal forms and diffraction quality, but no structure was solved in this paper; single study, preliminary report only","pmids":["22750877"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2020,"finding":"TgISP1 and TgISP3 were identified as likely substrates of the palmitoyl acyltransferase TgDHHC2: upon conditional depletion of TgDHHC2, ISP1 and ISP3 lose their membrane association, whereas depletion of TgDHHC14 does not affect them.","method":"Conditional knockdown of TgDHHC2 and TgDHHC14 followed by fluorescence microscopy and fractionation to assess membrane association of ISP1/ISP3","journal":"Cellular microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional depletion with defined molecular phenotype (loss of membrane association) for two separate enzymes, providing specificity; single lab, two constructs tested","pmids":["32329212"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"ISP1 is an apical cap IMC sub-compartment protein in Toxoplasma gondii that adopts a pleckstrin homology fold (without phospholipid binding activity), is anchored to the apical cap membrane via coordinated N-terminal myristoylation and palmitoylation (the latter catalyzed by TgDHHC2), and uses its C-terminal region to gate-keep the apical cap sub-compartment by actively excluding the paralogues ISP2 and ISP3 from this region, thereby establishing a hierarchical, interactive targeting system that organizes distinct IMC sub-compartments."},"narrative":{"mechanistic_narrative":"ISP1 is a Toxoplasma gondii inner membrane complex (IMC) sub-compartment protein that organizes the apical cap region and establishes a hierarchical protein-targeting system for the IMC [PMID:20844581]. It is targeted to the apical cap membrane through its N-terminal region, whose predicted coordinated myristoylation and palmitoylation are necessary and sufficient for apical cap localization [PMID:20844581]; the palmitoylation depends on the palmitoyl acyltransferase TgDHHC2, whose depletion abolishes ISP1 membrane association [PMID:32329212]. Beyond membrane anchoring, ISP1 functions as a gate-keeper: its C-terminal region actively excludes the paralogues ISP2 and ISP3 from the apical cap, and loss of ISP1 relocalizes both paralogues into this sub-compartment [PMID:20844581]. Structurally, ISP1 adopts a pleckstrin homology (PH) fold but does not bind phospholipids, with conserved surface residues at the canonical ligand-binding site apparently repurposed for protein-protein interactions [PMID:24675080].","teleology":[{"year":2010,"claim":"Established where ISP1 resides and how it gets there, defining the apical cap as a discrete IMC sub-compartment with a lipid-anchor-dependent targeting signal.","evidence":"Fluorescence microscopy with N-terminal truncation/mutation constructs and live imaging in T. gondii","pmids":["20844581"],"confidence":"High","gaps":["Direct biochemical demonstration of the myristoylation/palmitoylation modifications not shown","Enzyme responsible for the lipid modifications not identified in this study"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2010,"claim":"Revealed that ISP1 does more than localize itself — it enforces sub-compartment boundaries by excluding paralogues, defining a hierarchical targeting logic for IMC organization.","evidence":"Gene knockout of ISP1 with fluorescence microscopy of ISP2/ISP3 localization and C-terminal deletion mapping in T. gondii","pmids":["20844581"],"confidence":"High","gaps":["Molecular mechanism of exclusion (steric, binding-partner competition) not resolved","Direct interaction partners of the C-terminal region not identified"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2012,"claim":"Demonstrated that ISP1 contains a soluble, folded domain amenable to atomic-resolution structural study, enabling later mechanistic interpretation.","evidence":"Recombinant expression in E. coli, crystallization, and X-ray diffraction of N-terminally truncated ISP1","pmids":["22750877"],"confidence":"Medium","gaps":["No structure solved in this report","Fold and functional site not yet assigned"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2014,"claim":"Solved the fold and tested its presumed function, showing ISP1 is a PH-fold protein that has abandoned lipid binding in favor of a protein-interaction surface.","evidence":"X-ray crystallography of ISP1 (2.10 Å) and ISP3 (2.32 Å), phospholipid binding assays, and surface conservation mapping","pmids":["24675080"],"confidence":"High","gaps":["Identity of protein ligands binding the repurposed surface unknown","Structural basis of paralogue exclusion not directly demonstrated"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2020,"claim":"Identified the enzyme responsible for ISP1 membrane anchoring, linking the predicted palmitoylation to a specific acyltransferase with demonstrated specificity.","evidence":"Conditional knockdown of TgDHHC2 versus TgDHHC14 with microscopy and fractionation to assess ISP1/ISP3 membrane association in T. gondii","pmids":["32329212"],"confidence":"Medium","gaps":["Direct enzymatic modification of ISP1 by TgDHHC2 (in vitro acylation) not shown","Contribution of myristoylation versus palmitoylation to anchoring not disentangled"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The molecular basis by which the ISP1 C-terminal PH-fold surface excludes ISP2/ISP3 and the identity of its direct protein partners remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No binding partner identified for the repurposed ligand-binding surface","Mechanism connecting the PH fold to paralogue gate-keeping unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["ISP2 (EXCLUDED FROM APICAL CAP BY ISP1)","ISP3 (EXCLUDED FROM APICAL CAP BY ISP1)","TGDHHC2 (PALMITOYL ACYLTRANSFERASE, MEDIATES ISP1 MEMBRANE ASSOCIATION)"],"other_free_text":["N-terminal region carries predicted coordinated myristoylation and palmitoylation signals necessary and sufficient for apical cap targeting [#0].","Adopts a pleckstrin homology (PH) fold with no phospholipid binding activity; canonical ligand-binding site repurposed for protein-protein interactions [#2].","C-terminal region is required for exclusion of ISP2/ISP3 from the apical cap [#1]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"20844581","id":"PMC_20844581","title":"A novel family of Toxoplasma IMC proteins displays a hierarchical organization and functions in coordinating parasite division.","date":"2010","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/20844581","citation_count":192,"is_preprint":false},{"pmid":"22659420","id":"PMC_22659420","title":"Toxoplasma ISP4 is a central IMC sub-compartment protein whose localization depends on palmitoylation but not myristoylation.","date":"2012","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/22659420","citation_count":44,"is_preprint":false},{"pmid":"27548677","id":"PMC_27548677","title":"Virus-Like Nanoparticle Vaccine Confers Protection against Toxoplasma gondii.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/27548677","citation_count":33,"is_preprint":false},{"pmid":"21829561","id":"PMC_21829561","title":"Subcellular antigen location influences T-cell activation during acute infection with Toxoplasma gondii.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21829561","citation_count":33,"is_preprint":false},{"pmid":"25088010","id":"PMC_25088010","title":"Identification and characterization of Toxoplasma SIP, a conserved apicomplexan cytoskeleton protein involved in maintaining the shape, motility and virulence of the parasite.","date":"2014","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/25088010","citation_count":28,"is_preprint":false},{"pmid":"27586039","id":"PMC_27586039","title":"Cross-protection induced by Toxoplasma gondii virus-like particle vaccine upon intraperitoneal route challenge.","date":"2016","source":"Acta tropica","url":"https://pubmed.ncbi.nlm.nih.gov/27586039","citation_count":15,"is_preprint":false},{"pmid":"34634933","id":"PMC_34634933","title":"A Novel Toxoplasma Inner Membrane Complex Suture-Associated Protein Regulates Suture Protein Targeting and Colocalizes with Membrane Trafficking Machinery.","date":"2021","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/34634933","citation_count":12,"is_preprint":false},{"pmid":"24675080","id":"PMC_24675080","title":"The inner membrane complex sub-compartment proteins critical for replication of the apicomplexan parasite Toxoplasma gondii adopt a pleckstrin homology fold.","date":"2014","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24675080","citation_count":12,"is_preprint":false},{"pmid":"40801525","id":"PMC_40801525","title":"Co-dependent formation of the Toxoplasma gondii subpellicular microtubules and inner membrane skeleton.","date":"2025","source":"mBio","url":"https://pubmed.ncbi.nlm.nih.gov/40801525","citation_count":11,"is_preprint":false},{"pmid":"19820829","id":"PMC_19820829","title":"Toxoplasma gondii: further studies on the subpellicular network.","date":"2009","source":"Memorias do Instituto Oswaldo Cruz","url":"https://pubmed.ncbi.nlm.nih.gov/19820829","citation_count":11,"is_preprint":false},{"pmid":"38270431","id":"PMC_38270431","title":"Apical annuli are specialised sites of post-invasion secretion of dense granules in Toxoplasma.","date":"2024","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/38270431","citation_count":10,"is_preprint":false},{"pmid":"32329212","id":"PMC_32329212","title":"Two palmitoyl acyltransferases involved sequentially in the biogenesis of the inner membrane complex of Toxoplasma gondii.","date":"2020","source":"Cellular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/32329212","citation_count":7,"is_preprint":false},{"pmid":"22750877","id":"PMC_22750877","title":"Purification, crystallization and preliminary X-ray diffraction analysis of inner membrane complex (IMC) subcompartment protein 1 (ISP1) from Toxoplasma gondii.","date":"2012","source":"Acta crystallographica. Section F, Structural biology and crystallization communications","url":"https://pubmed.ncbi.nlm.nih.gov/22750877","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":23438,"output_tokens":1504,"usd":0.046437,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6639,"output_tokens":2398,"usd":0.046573,"stage2_stop_reason":"end_turn"},"total_usd":0.0,"stage1_batch_id":"msgbatch_01WgHz6kceqm573AGLyz57at","stage2_batch_id":"msgbatch_01LK4wDYj5zYquahv7gi9893","note":"batch pricing = 50% of standard","skipped":true,"corrective_rerun":"2026-09-10 wrong-gene rerun (round-4 rules)","corrective_reason":"paper list: removed papers about other genes"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"ISP1 localizes to the apical cap sub-compartment of the Toxoplasma IMC, dependent on N-terminal residues predicted for coordinated myristoylation and palmitoylation; the N-terminal region is necessary and sufficient for apical cap targeting.\",\n      \"method\": \"Fluorescence microscopy, N-terminal truncation/mutation analyses, live imaging\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct localization experiments with deletion analyses replicated across multiple constructs in a single rigorous study, functional consequence (mislocalization of ISP2/3) demonstrated\",\n      \"pmids\": [\"20844581\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"ISP1 acts as a 'gate-keeper' that excludes ISP2 and ISP3 from the apical cap: disruption of ISP1 causes dramatic relocalization of ISP2 and ISP3 to the apical cap, revealing a hierarchical targeting mechanism. The C-terminal region (beyond the N-terminal targeting domain) is required for this exclusion function.\",\n      \"method\": \"Gene knockout of ISP1 followed by fluorescence microscopy of ISP2/ISP3 localization; deletion analyses of C-terminal region\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic loss-of-function with defined molecular phenotype (relocalization of two paralogues), domain mapping with multiple deletion constructs, single rigorous study with multiple orthogonal methods\",\n      \"pmids\": [\"20844581\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Crystal structures of TgISP1 and TgISP3 were solved to 2.10 Å and 2.32 Å resolution, respectively, revealing that both proteins adopt a pleckstrin homology (PH) fold. Biochemical assays showed no phospholipid binding activity despite the PH fold; conserved surface residues map to the putative ligand-binding site, suggesting functional repurposing of this site for protein-protein interactions rather than lipid binding.\",\n      \"method\": \"X-ray crystallography (2.10 Å for ISP1, 2.32 Å for ISP3), phospholipid binding assays, conservation mapping\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure determination at high resolution combined with biochemical binding assays (negative phospholipid result) and conservation analysis, multiple orthogonal methods in one study\",\n      \"pmids\": [\"24675080\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Preliminary X-ray diffraction data for N-terminally truncated TgISP1 were obtained, with two crystal forms (space groups P4(1)32 or P4(3)32, and P2(1)2(1)2(1)) diffracting to 2.05 and 2.1 Å resolution, establishing that a soluble, structured domain exists in ISP1 amenable to structural characterization.\",\n      \"method\": \"Protein purification from E. coli, crystallization, X-ray diffraction analysis\",\n      \"journal\": \"Acta crystallographica. Section F, Structural biology and crystallization communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — crystallographic data collection established crystal forms and diffraction quality, but no structure was solved in this paper; single study, preliminary report only\",\n      \"pmids\": [\"22750877\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TgISP1 and TgISP3 were identified as likely substrates of the palmitoyl acyltransferase TgDHHC2: upon conditional depletion of TgDHHC2, ISP1 and ISP3 lose their membrane association, whereas depletion of TgDHHC14 does not affect them.\",\n      \"method\": \"Conditional knockdown of TgDHHC2 and TgDHHC14 followed by fluorescence microscopy and fractionation to assess membrane association of ISP1/ISP3\",\n      \"journal\": \"Cellular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional depletion with defined molecular phenotype (loss of membrane association) for two separate enzymes, providing specificity; single lab, two constructs tested\",\n      \"pmids\": [\"32329212\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"ISP1 is an apical cap IMC sub-compartment protein in Toxoplasma gondii that adopts a pleckstrin homology fold (without phospholipid binding activity), is anchored to the apical cap membrane via coordinated N-terminal myristoylation and palmitoylation (the latter catalyzed by TgDHHC2), and uses its C-terminal region to gate-keep the apical cap sub-compartment by actively excluding the paralogues ISP2 and ISP3 from this region, thereby establishing a hierarchical, interactive targeting system that organizes distinct IMC sub-compartments.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ISP1 is a Toxoplasma gondii inner membrane complex (IMC) sub-compartment protein that organizes the apical cap region and establishes a hierarchical protein-targeting system for the IMC [#0, #1]. It is targeted to the apical cap membrane through its N-terminal region, whose predicted coordinated myristoylation and palmitoylation are necessary and sufficient for apical cap localization [#0]; the palmitoylation depends on the palmitoyl acyltransferase TgDHHC2, whose depletion abolishes ISP1 membrane association [#4]. Beyond membrane anchoring, ISP1 functions as a gate-keeper: its C-terminal region actively excludes the paralogues ISP2 and ISP3 from the apical cap, and loss of ISP1 relocalizes both paralogues into this sub-compartment [#1]. Structurally, ISP1 adopts a pleckstrin homology (PH) fold but does not bind phospholipids, with conserved surface residues at the canonical ligand-binding site apparently repurposed for protein-protein interactions [#2].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established where ISP1 resides and how it gets there, defining the apical cap as a discrete IMC sub-compartment with a lipid-anchor-dependent targeting signal.\",\n      \"evidence\": \"Fluorescence microscopy with N-terminal truncation/mutation constructs and live imaging in T. gondii\",\n      \"pmids\": [\"20844581\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical demonstration of the myristoylation/palmitoylation modifications not shown\", \"Enzyme responsible for the lipid modifications not identified in this study\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Revealed that ISP1 does more than localize itself — it enforces sub-compartment boundaries by excluding paralogues, defining a hierarchical targeting logic for IMC organization.\",\n      \"evidence\": \"Gene knockout of ISP1 with fluorescence microscopy of ISP2/ISP3 localization and C-terminal deletion mapping in T. gondii\",\n      \"pmids\": [\"20844581\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular mechanism of exclusion (steric, binding-partner competition) not resolved\", \"Direct interaction partners of the C-terminal region not identified\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Demonstrated that ISP1 contains a soluble, folded domain amenable to atomic-resolution structural study, enabling later mechanistic interpretation.\",\n      \"evidence\": \"Recombinant expression in E. coli, crystallization, and X-ray diffraction of N-terminally truncated ISP1\",\n      \"pmids\": [\"22750877\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structure solved in this report\", \"Fold and functional site not yet assigned\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Solved the fold and tested its presumed function, showing ISP1 is a PH-fold protein that has abandoned lipid binding in favor of a protein-interaction surface.\",\n      \"evidence\": \"X-ray crystallography of ISP1 (2.10 Å) and ISP3 (2.32 Å), phospholipid binding assays, and surface conservation mapping\",\n      \"pmids\": [\"24675080\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of protein ligands binding the repurposed surface unknown\", \"Structural basis of paralogue exclusion not directly demonstrated\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified the enzyme responsible for ISP1 membrane anchoring, linking the predicted palmitoylation to a specific acyltransferase with demonstrated specificity.\",\n      \"evidence\": \"Conditional knockdown of TgDHHC2 versus TgDHHC14 with microscopy and fractionation to assess ISP1/ISP3 membrane association in T. gondii\",\n      \"pmids\": [\"32329212\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct enzymatic modification of ISP1 by TgDHHC2 (in vitro acylation) not shown\", \"Contribution of myristoylation versus palmitoylation to anchoring not disentangled\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular basis by which the ISP1 C-terminal PH-fold surface excludes ISP2/ISP3 and the identity of its direct protein partners remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No binding partner identified for the repurposed ligand-binding surface\", \"Mechanism connecting the PH fold to paralogue gate-keeping unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005515\", \"supporting_discovery_ids\": [1, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0070258\", \"supporting_discovery_ids\": [0, 1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0007163\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"ISP2 (excluded from apical cap by ISP1)\", \"ISP3 (excluded from apical cap by ISP1)\", \"TgDHHC2 (palmitoyl acyltransferase, mediates ISP1 membrane association)\"],\n    \"other_free_text\": [\n      \"N-terminal region carries predicted coordinated myristoylation and palmitoylation signals necessary and sufficient for apical cap targeting [#0].\",\n      \"Adopts a pleckstrin homology (PH) fold with no phospholipid binding activity; canonical ligand-binding site repurposed for protein-protein interactions [#2].\",\n      \"C-terminal region is required for exclusion of ISP2/ISP3 from the apical cap [#1].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}\n```","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_260820","name":"ISP1","product":"IMC sub-compartment protein ISP1","uniprot_acc":"A0A125YZB4","chromosome":"TGME49_chrVIIb","start_pos":2026953},{"strain":"GT1","gene_id":"TGGT1_260820","name":null,"product":"IMC sub-compartment protein ISP1","uniprot_acc":null,"chromosome":"TGGT1_chrVIIb","start_pos":2000787},{"strain":"RH88","gene_id":"TGRH88_069610","name":null,"product":"IMC sub-compartment protein ISP1","uniprot_acc":null,"chromosome":"CM023089","start_pos":2046374},{"strain":"VEG","gene_id":"TGVEG_260820","name":null,"product":"IMC sub-compartment protein ISP1","uniprot_acc":"B9PKK4","chromosome":"TGVEG_chrVIIb","start_pos":2041981}]}