{"gene":"TG_256070","gene_symbol":"CRK4","run_date":"2026-09-10T21:09:19","timeline":{"discoveries":[{"year":2017,"finding":"TgCrk4 is essential for tachyzoite growth and is specifically required for centrosome duplication during mitosis, as demonstrated by conditional tet-OFF knockdown showing growth arrest and centrosome duplication defects.","method":"Conditional tet-OFF knockdown with fluorescence microscopy to assess centrosome duplication","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional knockdown with defined cellular phenotype (centrosome duplication defect), single lab, single primary method","pmids":["28671988"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"finding":"TgCrk4 does not interact with any tested cyclin and is dynamically expressed during mitosis, suggesting it may not require a cyclin timing mechanism for its mitotic function.","method":"Conditional tet-OFF knockdown and co-immunoprecipitation (negative result for cyclin interaction)","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal interaction testing by co-IP, single lab; negative result is mechanistically informative","pmids":["28671988"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"TgCrk4 forms a complex with the cyclin partner TgCyc4, and together the TgCrk4-TgCyc4 complex regulates G2/M transition by repressing chromosome re-replication and centrosome reduplication, and acts upstream of the spindle assembly checkpoint.","method":"Conditional knockdown, quantitative fluorescence microscopy, co-immunoprecipitation, global phosphoproteomics","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (conditional KD, co-IP, phosphoproteomics, microscopy) in a single rigorous study establishing complex, substrates, and pathway position","pmids":["38600241"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"A dominant interactor of the TgCrk4-TgCyc4 complex, TgiRD1 (related to DNA replication licensing factor CDT1), was identified by proteomics; TgiRD1 also controls chromosome and centrosome reduplication but plays no role in G1-phase DNA replication licensing.","method":"Co-immunoprecipitation/proteomics followed by conditional knockdown with cell cycle phenotype readout","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP/MS identification plus functional KD, single lab, two orthogonal methods","pmids":["38600241"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"Global phosphoproteome analysis identified TgCrk4 substrates including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA, linking TgCrk4 kinase activity to centrosome and chromosome cycle regulation.","method":"Global phosphoproteomics upon TgCrk4 conditional knockdown","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — phosphoproteomics in conditional KD background identifies substrates, single lab, single method for substrate identification","pmids":["38600241"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"finding":"Phylogenetic and structural analyses indicate the Crk4-Cyc4 complex is restricted to a minor group of binary-dividing apicomplexans, suggesting it evolved specifically in this lineage.","method":"Phylogenetic analysis and structural comparison","journal":"The EMBO journal","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational/phylogenetic analysis only, no experimental validation of structural inference","pmids":["38600241"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"TgCrk4 is a CDK-related kinase that forms a complex with its cyclin partner TgCyc4 to regulate the G2/M transition in Toxoplasma gondii tachyzoites, specifically repressing centrosome reduplication and chromosome re-replication and acting upstream of the spindle assembly checkpoint, with identified substrates including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA; the complex also engages the TgiRD1 protein to coordinate chromosome and centrosome cycles, and appears restricted to binary-dividing apicomplexans."},"narrative":{"mechanistic_narrative":"TgCrk4 is a CDK-related kinase that governs the G2/M transition of Toxoplasma gondii tachyzoites, where it enforces the coordination of the chromosome and centrosome cycles [PMID:28671988, PMID:38600241]. It is essential for tachyzoite growth and specifically required for centrosome duplication during mitosis [PMID:28671988]. Functioning as a complex with its cyclin partner TgCyc4, TgCrk4 represses chromosome re-replication and centrosome reduplication and acts upstream of the spindle assembly checkpoint [PMID:38600241]. Its kinase activity targets substrates linking it to centrosome and chromosome cycle control, including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA [PMID:38600241], and the complex recruits a dominant interactor, TgiRD1 (related to the DNA replication licensing factor CDT1), which likewise restricts chromosome and centrosome reduplication without acting in G1-phase replication licensing [PMID:38600241]. Phylogenetic and structural analyses indicate the Crk4-Cyc4 complex is restricted to a minor group of binary-dividing apicomplexans, suggesting it evolved specifically in this lineage [PMID:38600241].","teleology":[{"year":2017,"claim":"Establishing whether TgCrk4 has a non-redundant cell-cycle function, conditional depletion showed it is essential for growth and specifically required for centrosome duplication, placing it within mitotic control.","evidence":"Conditional tet-OFF knockdown with fluorescence microscopy of centrosome duplication in T. gondii tachyzoites","pmids":["28671988"],"confidence":"Medium","gaps":["Cyclin partner and direct substrates not identified","Molecular mechanism of centrosome control unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2017,"claim":"To test whether TgCrk4 depends on a cyclin-timing mechanism, co-IP against a panel of cyclins gave a negative result, initially indicating no required cyclin partner.","evidence":"Co-immunoprecipitation (negative for cyclin interaction) plus expression profiling across mitosis","pmids":["28671988"],"confidence":"Medium","gaps":["The tested cyclin panel may have excluded the true partner (later shown to be TgCyc4)","Kinase activity requirements not defined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"Resolving the earlier negative cyclin result, TgCrk4 was shown to partner with TgCyc4, and the complex was placed mechanistically as a repressor of chromosome re-replication and centrosome reduplication acting upstream of the spindle assembly checkpoint.","evidence":"Conditional knockdown, quantitative fluorescence microscopy, co-IP and global phosphoproteomics in T. gondii","pmids":["38600241"],"confidence":"High","gaps":["Direct enzymatic assay of TgCrk4-TgCyc4 kinase activity not shown","How the complex is activated/timed at G2/M not fully defined"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"To connect kinase activity to phenotype, phosphoproteomics identified candidate substrates (TgORC4, TgCdc20, TgGCP2, TgPP2ACA) tying TgCrk4 to both chromosome and centrosome cycle machinery.","evidence":"Global phosphoproteomics in a TgCrk4 conditional knockdown background","pmids":["38600241"],"confidence":"Medium","gaps":["Direct in vitro phosphorylation of each substrate not demonstrated","Phosphosite-level functional consequences not tested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"To identify complex partners, proteomics revealed the CDT1-related protein TgiRD1 as a dominant interactor that also controls chromosome and centrosome reduplication but, unexpectedly, not G1-phase replication licensing.","evidence":"Co-IP/proteomics followed by conditional knockdown with cell-cycle phenotype readout in T. gondii","pmids":["38600241"],"confidence":"Medium","gaps":["Whether TgiRD1 is a substrate or purely a scaffold not resolved","Mechanism linking TgiRD1 to centrosome control unknown"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2024,"claim":"To assess conservation, phylogenetic and structural analysis indicated the Crk4-Cyc4 complex is restricted to a minor group of binary-dividing apicomplexans.","evidence":"Phylogenetic analysis and structural comparison (computational only)","pmids":["38600241"],"confidence":"Low","gaps":["Computational inference not experimentally validated","Functional conservation in other apicomplexans not tested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["TgCrk4-TgCyc4 kinase-cyclin complex"],"partners":["TGCYC4 (CYCLIN PARTNER)","TGIRD1 (CDT1-RELATED INTERACTOR)","TGORC4 (SUBSTRATE)","TGCDC20 (SUBSTRATE)","TGGCP2 (SUBSTRATE)","TGPP2ACA (SUBSTRATE)"],"other_free_text":["TgCrk4 is a CDK-related kinase essential for tachyzoite growth and centrosome duplication [#0].","The 2017 co-IP failed to detect a cyclin partner [#1], later resolved by identification of TgCyc4 as the partner in 2024 [#2].","The Crk4-Cyc4 complex is inferred to be restricted to binary-dividing apicomplexans by computational analysis [#5]."]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"10873834","id":"PMC_10873834","title":"Intracellular targets of cyclin-dependent kinase inhibitors: identification by affinity chromatography using immobilised inhibitors.","date":"2000","source":"Chemistry & biology","url":"https://pubmed.ncbi.nlm.nih.gov/10873834","citation_count":202,"is_preprint":false},{"pmid":"15023358","id":"PMC_15023358","title":"Protein kinases as targets for anti-parasitic chemotherapy.","date":"2004","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/15023358","citation_count":113,"is_preprint":false},{"pmid":"18703066","id":"PMC_18703066","title":"The cell cycle and Toxoplasma gondii cell division: tightly knit or loosely stitched?","date":"2008","source":"International journal for parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/18703066","citation_count":82,"is_preprint":false},{"pmid":"28671988","id":"PMC_28671988","title":"Checkpoints of apicomplexan cell division identified in Toxoplasma gondii.","date":"2017","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/28671988","citation_count":59,"is_preprint":false},{"pmid":"15811523","id":"PMC_15811523","title":"Characterization of two T. gondii CK1 isoforms.","date":"2005","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/15811523","citation_count":26,"is_preprint":false},{"pmid":"38600241","id":"PMC_38600241","title":"The Crk4-Cyc4 complex regulates G2/M transition in Toxoplasma gondii.","date":"2024","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/38600241","citation_count":16,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9774,"output_tokens":1676,"usd":0.027231,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":6922,"output_tokens":3248,"usd":0.057905,"stage2_stop_reason":"end_turn"},"total_usd":0.089116,"stage1_batch_id":"msgbatch_01TEPNZ4MCzJ7xtsNwosiDRk","stage2_batch_id":"msgbatch_01FQShM7n1sfCr4pWTDShmki","note":"batch pricing = 50% of standard","corrective_rerun":"2026-09-10 wrong-gene rerun (round-4 rules)","corrective_reason":"summary amended"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2017,\n      \"finding\": \"TgCrk4 is essential for tachyzoite growth and is specifically required for centrosome duplication during mitosis, as demonstrated by conditional tet-OFF knockdown showing growth arrest and centrosome duplication defects.\",\n      \"method\": \"Conditional tet-OFF knockdown with fluorescence microscopy to assess centrosome duplication\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional knockdown with defined cellular phenotype (centrosome duplication defect), single lab, single primary method\",\n      \"pmids\": [\"28671988\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TgCrk4 does not interact with any tested cyclin and is dynamically expressed during mitosis, suggesting it may not require a cyclin timing mechanism for its mitotic function.\",\n      \"method\": \"Conditional tet-OFF knockdown and co-immunoprecipitation (negative result for cyclin interaction)\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interaction testing by co-IP, single lab; negative result is mechanistically informative\",\n      \"pmids\": [\"28671988\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"TgCrk4 forms a complex with the cyclin partner TgCyc4, and together the TgCrk4-TgCyc4 complex regulates G2/M transition by repressing chromosome re-replication and centrosome reduplication, and acts upstream of the spindle assembly checkpoint.\",\n      \"method\": \"Conditional knockdown, quantitative fluorescence microscopy, co-immunoprecipitation, global phosphoproteomics\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (conditional KD, co-IP, phosphoproteomics, microscopy) in a single rigorous study establishing complex, substrates, and pathway position\",\n      \"pmids\": [\"38600241\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A dominant interactor of the TgCrk4-TgCyc4 complex, TgiRD1 (related to DNA replication licensing factor CDT1), was identified by proteomics; TgiRD1 also controls chromosome and centrosome reduplication but plays no role in G1-phase DNA replication licensing.\",\n      \"method\": \"Co-immunoprecipitation/proteomics followed by conditional knockdown with cell cycle phenotype readout\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP/MS identification plus functional KD, single lab, two orthogonal methods\",\n      \"pmids\": [\"38600241\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Global phosphoproteome analysis identified TgCrk4 substrates including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA, linking TgCrk4 kinase activity to centrosome and chromosome cycle regulation.\",\n      \"method\": \"Global phosphoproteomics upon TgCrk4 conditional knockdown\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phosphoproteomics in conditional KD background identifies substrates, single lab, single method for substrate identification\",\n      \"pmids\": [\"38600241\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Phylogenetic and structural analyses indicate the Crk4-Cyc4 complex is restricted to a minor group of binary-dividing apicomplexans, suggesting it evolved specifically in this lineage.\",\n      \"method\": \"Phylogenetic analysis and structural comparison\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational/phylogenetic analysis only, no experimental validation of structural inference\",\n      \"pmids\": [\"38600241\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TgCrk4-dependent G2/M checkpoint was detected using the ToxoFUCCIS cell cycle indicator, confirming TgCrk4's role at the G2/M transition within the composite cell cycle phase of Toxoplasma tachyzoites.\",\n      \"method\": \"Fluorescent Ubiquitination-based Cell Cycle Indicator (ToxoFUCCIS) with quantitative live and immunofluorescence microscopy\",\n      \"journal\": \"mBio\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell cycle indicator with quantitative microscopy confirms pathway position, single lab\",\n      \"pmids\": [\"40590555\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"TgCrk4 is a CDK-related kinase that forms a complex with its cyclin partner TgCyc4 to regulate the G2/M transition in Toxoplasma gondii tachyzoites, specifically repressing centrosome reduplication and chromosome re-replication and acting upstream of the spindle assembly checkpoint, with identified substrates including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA; the complex also engages the TgiRD1 protein to coordinate chromosome and centrosome cycles, and appears restricted to binary-dividing apicomplexans.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TgCrk4 is a CDK-related kinase that governs the G2/M transition of Toxoplasma gondii tachyzoites, where it enforces the coordination of the chromosome and centrosome cycles [#0, #2]. It is essential for tachyzoite growth and specifically required for centrosome duplication during mitosis [#0]. Functioning as a complex with its cyclin partner TgCyc4, TgCrk4 represses chromosome re-replication and centrosome reduplication and acts upstream of the spindle assembly checkpoint [#2], a checkpoint role at the G2/M transition confirmed with the ToxoFUCCIS live cell-cycle indicator [#6]. Its kinase activity targets substrates linking it to centrosome and chromosome cycle control, including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA [#4], and the complex recruits a dominant interactor, TgiRD1 (related to the DNA replication licensing factor CDT1), which likewise restricts chromosome and centrosome reduplication without acting in G1-phase replication licensing [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 2017,\n      \"claim\": \"Establishing whether TgCrk4 has a non-redundant cell-cycle function, conditional depletion showed it is essential for growth and specifically required for centrosome duplication, placing it within mitotic control.\",\n      \"evidence\": \"Conditional tet-OFF knockdown with fluorescence microscopy of centrosome duplication in T. gondii tachyzoites\",\n      \"pmids\": [\"28671988\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cyclin partner and direct substrates not identified\", \"Molecular mechanism of centrosome control unresolved\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"To test whether TgCrk4 depends on a cyclin-timing mechanism, co-IP against a panel of cyclins gave a negative result, initially indicating no required cyclin partner.\",\n      \"evidence\": \"Co-immunoprecipitation (negative for cyclin interaction) plus expression profiling across mitosis\",\n      \"pmids\": [\"28671988\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The tested cyclin panel may have excluded the true partner (later shown to be TgCyc4)\", \"Kinase activity requirements not defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolving the earlier negative cyclin result, TgCrk4 was shown to partner with TgCyc4, and the complex was placed mechanistically as a repressor of chromosome re-replication and centrosome reduplication acting upstream of the spindle assembly checkpoint.\",\n      \"evidence\": \"Conditional knockdown, quantitative fluorescence microscopy, co-IP and global phosphoproteomics in T. gondii\",\n      \"pmids\": [\"38600241\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct enzymatic assay of TgCrk4-TgCyc4 kinase activity not shown\", \"How the complex is activated/timed at G2/M not fully defined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To connect kinase activity to phenotype, phosphoproteomics identified candidate substrates (TgORC4, TgCdc20, TgGCP2, TgPP2ACA) tying TgCrk4 to both chromosome and centrosome cycle machinery.\",\n      \"evidence\": \"Global phosphoproteomics in a TgCrk4 conditional knockdown background\",\n      \"pmids\": [\"38600241\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct in vitro phosphorylation of each substrate not demonstrated\", \"Phosphosite-level functional consequences not tested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To identify complex partners, proteomics revealed the CDT1-related protein TgiRD1 as a dominant interactor that also controls chromosome and centrosome reduplication but, unexpectedly, not G1-phase replication licensing.\",\n      \"evidence\": \"Co-IP/proteomics followed by conditional knockdown with cell-cycle phenotype readout in T. gondii\",\n      \"pmids\": [\"38600241\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether TgiRD1 is a substrate or purely a scaffold not resolved\", \"Mechanism linking TgiRD1 to centrosome control unknown\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"To assess conservation, phylogenetic and structural analysis indicated the Crk4-Cyc4 complex is restricted to a minor group of binary-dividing apicomplexans.\",\n      \"evidence\": \"Phylogenetic analysis and structural comparison (computational only)\",\n      \"pmids\": [\"38600241\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Computational inference not experimentally validated\", \"Functional conservation in other apicomplexans not tested\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"To pinpoint the checkpoint position in real time, a live cell-cycle reporter confirmed a TgCrk4-dependent checkpoint at the G2/M transition within the composite tachyzoite cell cycle.\",\n      \"evidence\": \"ToxoFUCCIS fluorescent cell-cycle indicator with quantitative live and immunofluorescence microscopy\",\n      \"pmids\": [\"40590555\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular trigger of the checkpoint not defined\", \"Relationship to spindle assembly checkpoint effectors not mapped in real time\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TgCrk4-TgCyc4 activity is temporally activated and how its phosphorylation of specific substrates mechanistically blocks re-replication and centrosome reduplication remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct in vitro reconstitution of kinase-substrate reactions\", \"Structural basis of TgCrk4-TgCyc4 activation unknown\", \"Regulatory inputs upstream of the complex undefined\"],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004693\", \"supporting_discovery_ids\": [2, 4], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0016301\", \"supporting_discovery_ids\": [4], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005813\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0000086\", \"supporting_discovery_ids\": [2, 6], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0007088\", \"supporting_discovery_ids\": [2, 6], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0051726\", \"supporting_discovery_ids\": [0, 2, 3], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"GO:0010965\", \"supporting_discovery_ids\": [0, 2], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [\n      \"TgCrk4-TgCyc4 kinase-cyclin complex\"\n    ],\n    \"partners\": [\n      \"TgCyc4 (cyclin partner)\",\n      \"TgiRD1 (CDT1-related interactor)\",\n      \"TgORC4 (substrate)\",\n      \"TgCdc20 (substrate)\",\n      \"TgGCP2 (substrate)\",\n      \"TgPP2ACA (substrate)\"\n    ],\n    \"other_free_text\": [\n      \"TgCrk4 is a CDK-related kinase essential for tachyzoite growth and centrosome duplication [#0].\",\n      \"The 2017 co-IP failed to detect a cyclin partner [#1], later resolved by identification of TgCyc4 as the partner in 2024 [#2].\",\n      \"The Crk4-Cyc4 complex is inferred to be restricted to binary-dividing apicomplexans by computational analysis [#5].\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_256070","name":"CRK4","product":"CDK-related protein kinase CRK4","uniprot_acc":"A0A125YUD7","chromosome":"TGME49_chrVIIb","start_pos":4529496},{"strain":"GT1","gene_id":"TGGT1_256070","name":null,"product":"CMGC kinase","uniprot_acc":null,"chromosome":"TGGT1_chrVIIb","start_pos":4442536},{"strain":"RH88","gene_id":"TGRH88_073040","name":null,"product":"CMGC kinase","uniprot_acc":null,"chromosome":"CM023089","start_pos":4563720},{"strain":"VEG","gene_id":"TGVEG_256070","name":null,"product":"CMGC kinase","uniprot_acc":"A0A125YUD8","chromosome":"TGVEG_chrVIIb","start_pos":4549228}]}