{"gene":"TG_229260","gene_symbol":"BCC4","run_date":"2026-09-06T08:22:39","timeline":{"discoveries":[{"year":2022,"finding":"BCC4 and MORN1 together form a 'rubber band' complex at the basal end of the assembling daughter cytoskeleton, and this interaction is essential for cell division in T. gondii.","method":"Reciprocal proximity-based biotinylation (BioID) proteome mapping combined with disruption of component expression and functional readouts of cell division","journal":"Nature Communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal BioID proteomics plus loss-of-function disruption with defined cell division phenotype, single lab, multiple orthogonal methods","pmids":["35941170"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"finding":"BCC4 is assigned to one of four architecturally distinct basal complex subcomplexes whose composition changes dynamically in correlation with changes in basal complex function during daughter budding.","method":"Reciprocal proximity-based biotinylation proteomics and spatiotemporal disruption experiments","journal":"Nature Communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal BioID with spatial/temporal disruption analysis, single lab, two orthogonal methods","pmids":["35941170"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"BCC4 is a component of the Toxoplasma gondii basal complex that partners with MORN1 to form a 'rubber band' structure that sequesters the basal end of the assembling daughter cytoskeleton, playing an essential role in cell division as part of a dynamically regulated basal complex subcomplex."},"narrative":{"mechanistic_narrative":"BCC4 is a component of the Toxoplasma gondii basal complex, the ring-shaped structure at the basal end of the assembling daughter cytoskeleton, where it functions in cell division [PMID:35941170]. BCC4 partners with MORN1 to form a 'rubber band' complex that sequesters the basal end of the budding daughter cytoskeleton, an interaction essential for successful division [PMID:35941170]. Within the basal complex, BCC4 belongs to one of four architecturally distinct subcomplexes whose composition shifts dynamically in correlation with changing basal complex function during daughter budding [PMID:35941170]. Beyond its assignment to a MORN1-associated subcomplex and its requirement for cell division, no further mechanistic detail—molecular activity, structural basis of the interaction, or regulatory inputs—has been characterized in the available corpus.","teleology":[{"year":2022,"claim":"It was unknown which proteins organize the basal end of the daughter cytoskeleton during Toxoplasma division; identifying that BCC4 and MORN1 form an essential 'rubber band' complex established a defined molecular module underlying basal complex constriction.","evidence":"Reciprocal proximity-based biotinylation (BioID) proteome mapping with disruption of component expression and cell division readouts in T. gondii","pmids":["35941170"],"confidence":"Medium","gaps":["The direct biochemical nature of the BCC4-MORN1 interaction is not resolved by proximity labeling","No structural model of the 'rubber band' complex","The molecular activity of BCC4 itself is undefined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2022,"claim":"It was unclear whether the basal complex is a single static assembly; placing BCC4 in one of four architecturally distinct, dynamically composed subcomplexes established that the basal complex is functionally compartmentalized and remodeled during budding.","evidence":"Reciprocal proximity-based biotinylation proteomics and spatiotemporal disruption experiments in T. gondii","pmids":["35941170"],"confidence":"Medium","gaps":["The trigger and regulation of the compositional changes are not defined","The specific contribution of the BCC4-containing subcomplex to particular division steps is not isolated"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The molecular activity of BCC4, the structural basis of its interaction with MORN1, and the signals driving basal complex subcomplex remodeling remain unknown.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No enzymatic or structural function assigned to BCC4","Mechanism of subcomplex dynamic regulation uncharacterized","No cross-strain or cross-species characterization in the corpus"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["BCC4-MORN1 'rubber band' complex","basal complex subcomplex (one of four architecturally distinct subcomplexes)"],"partners":["MORN1"],"other_free_text":["BCC4-MORN1 interaction is essential for cell division in T. gondii [#0]","BCC4-containing basal complex subcomplex composition changes dynamically during daughter budding [#1]"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"35941170","id":"PMC_35941170","title":"Proteomic characterization of the Toxoplasma gondii cytokinesis machinery portrays an expanded hierarchy of its assembly and function.","date":"2022","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/35941170","citation_count":46,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":2793,"output_tokens":526,"usd":0.008134,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5197,"output_tokens":1584,"usd":0.032793,"stage2_stop_reason":"end_turn"},"total_usd":0.040927,"stage1_batch_id":"msgbatch_01WgHz6kceqm573AGLyz57at","stage2_batch_id":"msgbatch_01LK4wDYj5zYquahv7gi9893","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2022,\n      \"finding\": \"BCC4 and MORN1 together form a 'rubber band' complex at the basal end of the assembling daughter cytoskeleton, and this interaction is essential for cell division in T. gondii.\",\n      \"method\": \"Reciprocal proximity-based biotinylation (BioID) proteome mapping combined with disruption of component expression and functional readouts of cell division\",\n      \"journal\": \"Nature Communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal BioID proteomics plus loss-of-function disruption with defined cell division phenotype, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"35941170\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"BCC4 is assigned to one of four architecturally distinct basal complex subcomplexes whose composition changes dynamically in correlation with changes in basal complex function during daughter budding.\",\n      \"method\": \"Reciprocal proximity-based biotinylation proteomics and spatiotemporal disruption experiments\",\n      \"journal\": \"Nature Communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal BioID with spatial/temporal disruption analysis, single lab, two orthogonal methods\",\n      \"pmids\": [\"35941170\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"BCC4 is a component of the Toxoplasma gondii basal complex that partners with MORN1 to form a 'rubber band' structure that sequesters the basal end of the assembling daughter cytoskeleton, playing an essential role in cell division as part of a dynamically regulated basal complex subcomplex.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BCC4 is a component of the Toxoplasma gondii basal complex, the ring-shaped structure at the basal end of the assembling daughter cytoskeleton, where it functions in cell division [#0]. BCC4 partners with MORN1 to form a 'rubber band' complex that sequesters the basal end of the budding daughter cytoskeleton, an interaction essential for successful division [#0]. Within the basal complex, BCC4 belongs to one of four architecturally distinct subcomplexes whose composition shifts dynamically in correlation with changing basal complex function during daughter budding [#1]. Beyond its assignment to a MORN1-associated subcomplex and its requirement for cell division, no further mechanistic detail—molecular activity, structural basis of the interaction, or regulatory inputs—has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2022,\n      \"claim\": \"It was unknown which proteins organize the basal end of the daughter cytoskeleton during Toxoplasma division; identifying that BCC4 and MORN1 form an essential 'rubber band' complex established a defined molecular module underlying basal complex constriction.\",\n      \"evidence\": \"Reciprocal proximity-based biotinylation (BioID) proteome mapping with disruption of component expression and cell division readouts in T. gondii\",\n      \"pmids\": [\n        \"35941170\"\n      ],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The direct biochemical nature of the BCC4-MORN1 interaction is not resolved by proximity labeling\",\n        \"No structural model of the 'rubber band' complex\",\n        \"The molecular activity of BCC4 itself is undefined\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"It was unclear whether the basal complex is a single static assembly; placing BCC4 in one of four architecturally distinct, dynamically composed subcomplexes established that the basal complex is functionally compartmentalized and remodeled during budding.\",\n      \"evidence\": \"Reciprocal proximity-based biotinylation proteomics and spatiotemporal disruption experiments in T. gondii\",\n      \"pmids\": [\n        \"35941170\"\n      ],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The trigger and regulation of the compositional changes are not defined\",\n        \"The specific contribution of the BCC4-containing subcomplex to particular division steps is not isolated\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular activity of BCC4, the structural basis of its interaction with MORN1, and the signals driving basal complex subcomplex remodeling remain unknown.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No enzymatic or structural function assigned to BCC4\",\n        \"Mechanism of subcomplex dynamic regulation uncharacterized\",\n        \"No cross-strain or cross-species characterization in the corpus\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\n        \"term_id\": \"basal complex (T. gondii daughter cytoskeleton basal end)\",\n        \"supporting_discovery_ids\": [0, 1],\n        \"attribution\": [\n          {\n            \"species\": \"Toxoplasma gondii\",\n            \"strain\": \"\"\n          }\n        ]\n      }\n    ],\n    \"pathway\": [\n      {\n        \"term_id\": \"GO:0051301\",\n        \"supporting_discovery_ids\": [0, 1],\n        \"attribution\": [\n          {\n            \"species\": \"Toxoplasma gondii\",\n            \"strain\": \"\"\n          }\n        ]\n      }\n    ],\n    \"complexes\": [\n      \"BCC4-MORN1 'rubber band' complex\",\n      \"basal complex subcomplex (one of four architecturally distinct subcomplexes)\"\n    ],\n    \"partners\": [\n      \"MORN1\"\n    ],\n    \"other_free_text\": [\n      \"BCC4-MORN1 interaction is essential for cell division in T. gondii [#0]\",\n      \"BCC4-containing basal complex subcomplex composition changes dynamically during daughter budding [#1]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_229260","name":"BCC4","product":"basal complex component BCC4","uniprot_acc":"A0A125YYW1","chromosome":"TGME49_chrVIII","start_pos":113547},{"strain":"GT1","gene_id":"TGGT1_229260","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrVIII","start_pos":112028},{"strain":"RH88","gene_id":"TGRH88_073990","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023089","start_pos":5223332},{"strain":"VEG","gene_id":"TGVEG_229260","name":null,"product":"hypothetical protein","uniprot_acc":"B6KJ47","chromosome":"TGVEG_chrVIII","start_pos":117698}]}