{"gene":"PF3D7_0911200","run_date":"2026-09-08T16:26:55","timeline":{"discoveries":[{"year":2022,"finding":"SKA1 (PF3D7_0911200) was identified as a component of the apicomplexan kinetochore through interactomics and deep homology searches, placing it among 13 previously unknown kinetochore components in Apicomplexa with a discrete subkinetochore localization.","method":"Interactomics (pulldown/co-immunoprecipitation) combined with deep homology searches and subcellular localization imaging","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — interactomics plus imaging in a single study; establishes kinetochore membership but no detailed mechanistic characterization of SKA1 itself","pmids":["36006241"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2026,"finding":"In Plasmodium berghei, SKA1 (PF3D7_0911200) accumulates on the meiotic spindle and kinetochores during zygote development but is not detected during male microgametogenesis, indicating a meiosis-specific role in kinetochore–microtubule attachment regulation.","method":"Live fluorescence imaging of SKA1-mNG-3xHA together with the kinetochore marker NUF2-mScI across male gametogenesis and zygote/ookinete development stages","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct live-imaging localization across multiple lifecycle stages in three independent biological replicates; functional consequence inferred from stage-specific absence rather than direct loss-of-function of SKA1 itself","pmids":["42323312"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]}],"current_model":"SKA1 (PF3D7_0911200) is a divergent kinetochore component in apicomplexan parasites that localizes to the meiotic spindle and kinetochores in Plasmodium berghei zygotes but is absent from male microgametocytes, consistent with a meiosis-specific role in kinetochore–microtubule attachment; its precise biochemical function within the kinetochore remains uncharacterized."},"narrative":{"mechanistic_narrative":"SKA1 (PF3D7_0911200) is a divergent kinetochore component of apicomplexan parasites, identified through interactomics and deep homology searches as one of a set of previously unrecognized kinetochore proteins with a discrete subkinetochore localization [PMID:36006241]. In Plasmodium berghei, SKA1 accumulates on the meiotic spindle and kinetochores during zygote development but is undetectable during male microgametogenesis, a stage-specific expression pattern consistent with a meiosis-restricted role in kinetochore–microtubule attachment [PMID:42323312]. Beyond its assignment to the kinetochore and its meiotic localization profile, the biochemical function of SKA1 within the kinetochore has not been characterized in the available corpus.","teleology":[{"year":2022,"claim":"Whether apicomplexan parasites possess a definable kinetochore protein inventory was unresolved; identifying SKA1 as a kinetochore component established its membership in the parasite kinetochore machinery.","evidence":"Interactomics (pulldown/co-immunoprecipitation) combined with deep homology searches and subcellular localization imaging in P. falciparum and P. berghei","pmids":["36006241"],"confidence":"Medium","gaps":["No direct biochemical function or interaction partner of SKA1 within the kinetochore was defined","Discrete subkinetochore localization was described but not mechanistically dissected","No loss-of-function analysis of SKA1 itself"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2026,"claim":"When and where SKA1 acts across the parasite life cycle was unknown; live imaging across gametogenesis and zygote development localized SKA1 to the meiotic spindle and kinetochores while showing its absence from male microgametogenesis, pointing to a meiosis-specific role.","evidence":"Live fluorescence imaging of SKA1-mNG-3xHA with the kinetochore marker NUF2-mScI across life-cycle stages in P. berghei","pmids":["42323312"],"confidence":"Medium","gaps":["Functional role inferred from stage-specific absence, not from direct loss-of-function of SKA1","No demonstration that SKA1 mediates kinetochore–microtubule attachment biochemically","Interaction with NUF2 or other kinetochore proteins not directly tested"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":null,"claim":"The biochemical mechanism by which SKA1 contributes to kinetochore function and the phenotypic consequence of its loss remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct loss-of-function/knockout phenotype for SKA1 reported","No structural model or defined kinetochore-microtubule binding activity","Direct interaction partners within the kinetochore not established"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Apicomplexan kinetochore"],"partners":[],"other_free_text":["Identified as one of 13 previously unknown apicomplexan kinetochore components with discrete subkinetochore localization [#0]","In P. berghei, present on meiotic spindle/kinetochores in zygotes but absent from male microgametogenesis [#1]","Imaged alongside the kinetochore marker NUF2 but a direct SKA1-NUF2 interaction was not tested [#1]"]}},"prefetch_data":{},"corpus_meta":[{"pmid":"36006241","id":"PMC_36006241","title":"Composition and organization of kinetochores show plasticity in apicomplexan chromosome segregation.","date":"2022","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/36006241","citation_count":31,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"42323312","id":"","title":"A modular chromosomal passenger complex rewires chromosome segregation in Plasmodium berghei.","date":"2026","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/42323312","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["SKA1"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4469,"output_tokens":682,"usd":0.011818,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5285,"output_tokens":1504,"usd":0.032012,"stage2_stop_reason":"end_turn"},"total_usd":0.04383,"stage1_batch_id":"msgbatch_01NE1MTa8x1hW7Lo4tAaNzY1","stage2_batch_id":"msgbatch_0141vaQdeFvbo2q39AinvXM9","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2022,\n      \"finding\": \"SKA1 (PF3D7_0911200) was identified as a component of the apicomplexan kinetochore through interactomics and deep homology searches, placing it among 13 previously unknown kinetochore components in Apicomplexa with a discrete subkinetochore localization.\",\n      \"method\": \"Interactomics (pulldown/co-immunoprecipitation) combined with deep homology searches and subcellular localization imaging\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — interactomics plus imaging in a single study; establishes kinetochore membership but no detailed mechanistic characterization of SKA1 itself\",\n      \"pmids\": [\"36006241\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In Plasmodium berghei, SKA1 (PF3D7_0911200) accumulates on the meiotic spindle and kinetochores during zygote development but is not detected during male microgametogenesis, indicating a meiosis-specific role in kinetochore–microtubule attachment regulation.\",\n      \"method\": \"Live fluorescence imaging of SKA1-mNG-3xHA together with the kinetochore marker NUF2-mScI across male gametogenesis and zygote/ookinete development stages\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct live-imaging localization across multiple lifecycle stages in three independent biological replicates; functional consequence inferred from stage-specific absence rather than direct loss-of-function of SKA1 itself\",\n      \"pmids\": [\"42323312\"],\n      \"is_preprint\": false,\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    }\n  ],\n  \"current_model\": \"SKA1 (PF3D7_0911200) is a divergent kinetochore component in apicomplexan parasites that localizes to the meiotic spindle and kinetochores in Plasmodium berghei zygotes but is absent from male microgametocytes, consistent with a meiosis-specific role in kinetochore–microtubule attachment; its precise biochemical function within the kinetochore remains uncharacterized.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"SKA1 (PF3D7_0911200) is a divergent kinetochore component of apicomplexan parasites, identified through interactomics and deep homology searches as one of a set of previously unrecognized kinetochore proteins with a discrete subkinetochore localization [#0]. In Plasmodium berghei, SKA1 accumulates on the meiotic spindle and kinetochores during zygote development but is undetectable during male microgametogenesis, a stage-specific expression pattern consistent with a meiosis-restricted role in kinetochore\\u2013microtubule attachment [#1]. Beyond its assignment to the kinetochore and its meiotic localization profile, the biochemical function of SKA1 within the kinetochore has not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether apicomplexan parasites possess a definable kinetochore protein inventory was unresolved; identifying SKA1 as a kinetochore component established its membership in the parasite kinetochore machinery.\",\n      \"evidence\": \"Interactomics (pulldown/co-immunoprecipitation) combined with deep homology searches and subcellular localization imaging in P. falciparum and P. berghei\",\n      \"pmids\": [\"36006241\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct biochemical function or interaction partner of SKA1 within the kinetochore was defined\",\n        \"Discrete subkinetochore localization was described but not mechanistically dissected\",\n        \"No loss-of-function analysis of SKA1 itself\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"When and where SKA1 acts across the parasite life cycle was unknown; live imaging across gametogenesis and zygote development localized SKA1 to the meiotic spindle and kinetochores while showing its absence from male microgametogenesis, pointing to a meiosis-specific role.\",\n      \"evidence\": \"Live fluorescence imaging of SKA1-mNG-3xHA with the kinetochore marker NUF2-mScI across life-cycle stages in P. berghei\",\n      \"pmids\": [\"42323312\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Functional role inferred from stage-specific absence, not from direct loss-of-function of SKA1\",\n        \"No demonstration that SKA1 mediates kinetochore\\u2013microtubule attachment biochemically\",\n        \"Interaction with NUF2 or other kinetochore proteins not directly tested\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The biochemical mechanism by which SKA1 contributes to kinetochore function and the phenotypic consequence of its loss remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No direct loss-of-function/knockout phenotype for SKA1 reported\",\n        \"No structural model or defined kinetochore-microtubule binding activity\",\n        \"Direct interaction partners within the kinetochore not established\"\n      ],\n      \"attribution\": []\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0000776\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005876\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0051321\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"complexes\": [\"Apicomplexan kinetochore\"],\n    \"partners\": [],\n    \"other_free_text\": [\n      \"Identified as one of 13 previously unknown apicomplexan kinetochore components with discrete subkinetochore localization [#0]\",\n      \"In P. berghei, present on meiotic spindle/kinetochores in zygotes but absent from male microgametogenesis [#1]\",\n      \"Imaged alongside the kinetochore marker NUF2 but a direct SKA1-NUF2 interaction was not tested [#1]\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0911200","name":null,"product":"spindle and kinetochore-associated protein 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_0812300","name":null,"product":"conserved Plasmodium protein, unknown function","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_0709200","name":null,"product":"spindle and kinetochore-associated protein 1, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"SKA1","evaluation":null}