{"gene":"TG_201840","gene_symbol":"ASP1","run_date":"2026-09-07T10:25:42","timeline":{"discoveries":[{"year":2007,"finding":"TgASP1 is proteolytically matured and shows a dynamic, cell-cycle-dependent subcellular localization: in non-dividing tachyzoites it localizes to punctate structures associated with the secretory pathway, and during replication it relocalizes to the nascent inner membrane complex (IMC) of daughter cells before coalescing again at the end of division.","method":"Subcellular localization by fluorescence microscopy and analysis of proteolytic maturation through the cell cycle","journal":"Traffic","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiment with cell-cycle-dependent functional context, single lab, two complementary approaches (maturation assay + imaging)","pmids":["17547703"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"finding":"Conventional knockout of TgASP1 demonstrated that TgASP1 is not essential for tachyzoite survival or for proper inner membrane complex (IMC) biogenesis, despite its localization near the nascent IMC during replication.","method":"Conventional gene knockout with phenotypic analysis of tachyzoite growth and IMC biogenesis","journal":"Experimental parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype readout (growth and IMC formation), single lab","pmids":["21616070"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2020,"finding":"ASP1 resides in the lysosome-like vacuolar compartment (VAC) of T. gondii and its correct maturation depends on cathepsin protease L (CPL); however, ASP1 plays a dispensable role in VAC protein digestion.","method":"Subcellular fractionation/localization, genetic ablation of CPL and CPB with protein digestion assays, maturation analysis","journal":"mSphere","confidence":"High","confidence_rationale":"Tier 2 / Strong — localization established, CPL-dependent maturation demonstrated, dispensability confirmed by KO with proteolysis assay; multiple orthogonal methods in one rigorous study","pmids":["32051238"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2013,"finding":"Antibodies raised against recombinant TgASP1 localized the protein primarily to the tip of T. gondii tachyzoites, and TgASP1 was identified as a membrane-associated protein.","method":"Immunofluorescence localization using antibodies raised against recombinant TgASP1 expressed in E. coli","journal":"Parasites & vectors","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single localization method using heterologous antibodies; no functional consequence established","pmids":["23768047"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]}],"current_model":"TgASP1 is a coccidian-specific aspartic protease that undergoes CPL-dependent proteolytic maturation and localizes to the vacuolar compartment (VAC) in non-dividing tachyzoites, dynamically relocalizing to the nascent inner membrane complex during daughter-cell replication; despite this cell-cycle-associated behavior, genetic knockout experiments establish that TgASP1 is dispensable for tachyzoite growth, IMC biogenesis, and VAC-mediated protein digestion."},"narrative":{"mechanistic_narrative":"TgASP1 is a coccidian aspartic protease of Toxoplasma gondii that undergoes proteolytic maturation and displays a dynamic, cell-cycle-dependent subcellular distribution: in non-dividing tachyzoites it occupies punctate structures of the secretory pathway, and during replication it relocalizes to the nascent inner membrane complex (IMC) of daughter cells before coalescing again as division completes [PMID:17547703]. It resides in the lysosome-like vacuolar compartment (VAC), where its correct maturation depends on cathepsin protease L (CPL) [PMID:32051238]. Despite this cell-cycle-associated behavior and IMC-proximal localization, TgASP1 is dispensable: genetic knockout leaves tachyzoite growth and IMC biogenesis intact [PMID:21616070], and it plays no essential role in VAC-mediated protein digestion [PMID:32051238]. Beyond these localization, maturation, and dispensability findings, no substrate or catalytic pathway for TgASP1 has been characterized in the available corpus.","teleology":[{"year":2007,"claim":"Establishing where and when TgASP1 acts, this work showed the protease is proteolytically matured and traffics dynamically with the cell cycle, hinting at a role in daughter-cell (IMC) assembly.","evidence":"Fluorescence microscopy localization and maturation analysis across the cell cycle in T. gondii tachyzoites","pmids":["17547703"],"confidence":"Medium","gaps":["No substrate or catalytic activity demonstrated","Functional consequence of IMC relocalization untested","Trafficking machinery directing relocalization unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2011,"claim":"Testing whether the IMC-proximal localization reflected an essential role in daughter-cell membrane assembly, knockout showed TgASP1 is dispensable for tachyzoite growth and IMC biogenesis, decoupling its localization from an essential function.","evidence":"Conventional gene knockout with growth and IMC biogenesis phenotyping in T. gondii tachyzoites","pmids":["21616070"],"confidence":"Medium","gaps":["Does not identify the protein's actual function","Redundancy with other proteases not excluded","Life-cycle stages beyond tachyzoite untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2013,"claim":"An independent localization attempt using heterologous antibodies placed TgASP1 at the tachyzoite tip and classified it as membrane-associated, adding a localization datum that diverges from later VAC/IMC assignments.","evidence":"Immunofluorescence with antibodies raised against recombinant TgASP1 in RH strain","pmids":["23768047"],"confidence":"Low","gaps":["Single method with heterologous antibodies, no functional readout","Apical-tip localization not corroborated by other studies","Antibody specificity not orthogonally validated"],"attribution":[{"species":"Toxoplasma gondii","strain":"RH"}]},{"year":2020,"claim":"Resolving the resting-state compartment and maturation pathway, this work placed TgASP1 in the lysosome-like VAC, showed its maturation requires CPL, and demonstrated it is dispensable for VAC protein digestion.","evidence":"Subcellular fractionation/localization, CPL and CPB genetic ablation, protein digestion and maturation assays in T. gondii","pmids":["32051238"],"confidence":"High","gaps":["Endogenous substrate of TgASP1 still unidentified","Reason for CPL-dependent maturation unclear","Biological purpose of the enzyme remains undefined despite known localization"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The physiological substrate and biological function of TgASP1 remain unknown: it is a matured, VAC-localized, cell-cycle-dynamic aspartic protease that is dispensable for every process so far tested.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No proteolytic substrate identified","No essential process assigned","Function beyond the tachyzoite stage uncharacterized"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["CPL (CATHEPSIN PROTEASE L) — REQUIRED FOR TGASP1 MATURATION [#2]"],"other_free_text":["TgASP1 is proteolytically matured and dispensable for tachyzoite growth, IMC biogenesis, and VAC protein digestion [#1, #2].","During replication TgASP1 relocalizes to the nascent inner membrane complex of daughter cells, coalescing at the end of division [#0]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"15358257","id":"PMC_15358257","title":"Host cell invasion by the apicomplexans: the significance of microneme protein proteolysis.","date":"2004","source":"Current opinion in microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/15358257","citation_count":72,"is_preprint":false},{"pmid":"17547703","id":"PMC_17547703","title":"A family of aspartic proteases and a novel, dynamic and cell-cycle-dependent protease localization in the secretory pathway of Toxoplasma gondii.","date":"2007","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/17547703","citation_count":49,"is_preprint":false},{"pmid":"23768047","id":"PMC_23768047","title":"Identification and characterization of Toxoplasma gondii aspartic protease 1 as a novel vaccine candidate against toxoplasmosis.","date":"2013","source":"Parasites & vectors","url":"https://pubmed.ncbi.nlm.nih.gov/23768047","citation_count":31,"is_preprint":false},{"pmid":"32051238","id":"PMC_32051238","title":"Toxoplasma Cathepsin Protease B and Aspartyl Protease 1 Are Dispensable for Endolysosomal Protein Digestion.","date":"2020","source":"mSphere","url":"https://pubmed.ncbi.nlm.nih.gov/32051238","citation_count":17,"is_preprint":false},{"pmid":"28238685","id":"PMC_28238685","title":"Immunization with Toxoplasma gondii aspartic protease 3 increases survival time of infected mice.","date":"2017","source":"Acta tropica","url":"https://pubmed.ncbi.nlm.nih.gov/28238685","citation_count":17,"is_preprint":false},{"pmid":"21616070","id":"PMC_21616070","title":"Toxoplasma gondii aspartic protease 1 is not essential in tachyzoites.","date":"2011","source":"Experimental parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/21616070","citation_count":10,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4950,"output_tokens":1050,"usd":0.0153,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5964,"output_tokens":2147,"usd":0.041747,"stage2_stop_reason":"end_turn"},"total_usd":0.057047,"stage1_batch_id":"msgbatch_018xTxyBPcQFK9jdgubtxgsj","stage2_batch_id":"msgbatch_01UiG5BTaJP7BvKKL6RLeyv2","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"TgASP1 is proteolytically matured and shows a dynamic, cell-cycle-dependent subcellular localization: in non-dividing tachyzoites it localizes to punctate structures associated with the secretory pathway, and during replication it relocalizes to the nascent inner membrane complex (IMC) of daughter cells before coalescing again at the end of division.\",\n      \"method\": \"Subcellular localization by fluorescence microscopy and analysis of proteolytic maturation through the cell cycle\",\n      \"journal\": \"Traffic\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment with cell-cycle-dependent functional context, single lab, two complementary approaches (maturation assay + imaging)\",\n      \"pmids\": [\"17547703\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Conventional knockout of TgASP1 demonstrated that TgASP1 is not essential for tachyzoite survival or for proper inner membrane complex (IMC) biogenesis, despite its localization near the nascent IMC during replication.\",\n      \"method\": \"Conventional gene knockout with phenotypic analysis of tachyzoite growth and IMC biogenesis\",\n      \"journal\": \"Experimental parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype readout (growth and IMC formation), single lab\",\n      \"pmids\": [\"21616070\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ASP1 resides in the lysosome-like vacuolar compartment (VAC) of T. gondii and its correct maturation depends on cathepsin protease L (CPL); however, ASP1 plays a dispensable role in VAC protein digestion.\",\n      \"method\": \"Subcellular fractionation/localization, genetic ablation of CPL and CPB with protein digestion assays, maturation analysis\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — localization established, CPL-dependent maturation demonstrated, dispensability confirmed by KO with proteolysis assay; multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"32051238\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Antibodies raised against recombinant TgASP1 localized the protein primarily to the tip of T. gondii tachyzoites, and TgASP1 was identified as a membrane-associated protein.\",\n      \"method\": \"Immunofluorescence localization using antibodies raised against recombinant TgASP1 expressed in E. coli\",\n      \"journal\": \"Parasites & vectors\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single localization method using heterologous antibodies; no functional consequence established\",\n      \"pmids\": [\"23768047\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    }\n  ],\n  \"current_model\": \"TgASP1 is a coccidian-specific aspartic protease that undergoes CPL-dependent proteolytic maturation and localizes to the vacuolar compartment (VAC) in non-dividing tachyzoites, dynamically relocalizing to the nascent inner membrane complex during daughter-cell replication; despite this cell-cycle-associated behavior, genetic knockout experiments establish that TgASP1 is dispensable for tachyzoite growth, IMC biogenesis, and VAC-mediated protein digestion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TgASP1 is a coccidian aspartic protease of Toxoplasma gondii that undergoes proteolytic maturation and displays a dynamic, cell-cycle-dependent subcellular distribution: in non-dividing tachyzoites it occupies punctate structures of the secretory pathway, and during replication it relocalizes to the nascent inner membrane complex (IMC) of daughter cells before coalescing again as division completes [#0]. It resides in the lysosome-like vacuolar compartment (VAC), where its correct maturation depends on cathepsin protease L (CPL) [#2]. Despite this cell-cycle-associated behavior and IMC-proximal localization, TgASP1 is dispensable: genetic knockout leaves tachyzoite growth and IMC biogenesis intact [#1], and it plays no essential role in VAC-mediated protein digestion [#2]. Beyond these localization, maturation, and dispensability findings, no substrate or catalytic pathway for TgASP1 has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2007,\n      \"claim\": \"Establishing where and when TgASP1 acts, this work showed the protease is proteolytically matured and traffics dynamically with the cell cycle, hinting at a role in daughter-cell (IMC) assembly.\",\n      \"evidence\": \"Fluorescence microscopy localization and maturation analysis across the cell cycle in T. gondii tachyzoites\",\n      \"pmids\": [\"17547703\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No substrate or catalytic activity demonstrated\", \"Functional consequence of IMC relocalization untested\", \"Trafficking machinery directing relocalization unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Testing whether the IMC-proximal localization reflected an essential role in daughter-cell membrane assembly, knockout showed TgASP1 is dispensable for tachyzoite growth and IMC biogenesis, decoupling its localization from an essential function.\",\n      \"evidence\": \"Conventional gene knockout with growth and IMC biogenesis phenotyping in T. gondii tachyzoites\",\n      \"pmids\": [\"21616070\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not identify the protein's actual function\", \"Redundancy with other proteases not excluded\", \"Life-cycle stages beyond tachyzoite untested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"An independent localization attempt using heterologous antibodies placed TgASP1 at the tachyzoite tip and classified it as membrane-associated, adding a localization datum that diverges from later VAC/IMC assignments.\",\n      \"evidence\": \"Immunofluorescence with antibodies raised against recombinant TgASP1 in RH strain\",\n      \"pmids\": [\"23768047\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single method with heterologous antibodies, no functional readout\", \"Apical-tip localization not corroborated by other studies\", \"Antibody specificity not orthogonally validated\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"RH\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Resolving the resting-state compartment and maturation pathway, this work placed TgASP1 in the lysosome-like VAC, showed its maturation requires CPL, and demonstrated it is dispensable for VAC protein digestion.\",\n      \"evidence\": \"Subcellular fractionation/localization, CPL and CPB genetic ablation, protein digestion and maturation assays in T. gondii\",\n      \"pmids\": [\"32051238\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous substrate of TgASP1 still unidentified\", \"Reason for CPL-dependent maturation unclear\", \"Biological purpose of the enzyme remains undefined despite known localization\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The physiological substrate and biological function of TgASP1 remain unknown: it is a matured, VAC-localized, cell-cycle-dynamic aspartic protease that is dispensable for every process so far tested.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No proteolytic substrate identified\", \"No essential process assigned\", \"Function beyond the tachyzoite stage uncharacterized\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004190\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0070258\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0016485\", \"supporting_discovery_ids\": [2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"CPL (cathepsin protease L) — required for TgASP1 maturation [#2]\"\n    ],\n    \"other_free_text\": [\n      \"TgASP1 is proteolytically matured and dispensable for tachyzoite growth, IMC biogenesis, and VAC protein digestion [#1, #2].\",\n      \"During replication TgASP1 relocalizes to the nascent inner membrane complex of daughter cells, coalescing at the end of division [#0].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_201840","name":"ASP1","product":"aspartyl protease ASP1","uniprot_acc":"S8F3D0","chromosome":"TGME49_chrVIIa","start_pos":3748209},{"strain":"GT1","gene_id":"TGGT1_201840","name":null,"product":"aspartyl protease ASP1","uniprot_acc":null,"chromosome":"TGGT1_chrVIIa","start_pos":3648103},{"strain":"RH88","gene_id":"TGRH88_037100","name":null,"product":"aspartyl protease ASP1","uniprot_acc":null,"chromosome":"CM023088","start_pos":3842524},{"strain":"VEG","gene_id":"TGVEG_201840","name":null,"product":"aspartyl protease ASP1","uniprot_acc":"B9QG15","chromosome":"TGVEG_chrVIIa","start_pos":3835827}]}