{"gene":"EFCAB9","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":2019,"finding":"EFCAB9 is a cytoplasmic, bifunctional Ca2+ sensor that directly interacts with CATSPERζ (a subunit of the CatSper channel) in a Ca2+-dependent manner and dissociates from it at elevated pH, thereby modulating both CatSper channel activity and the linear organization of CatSper Ca2+ signaling nanodomains along the sperm tail.","method":"Knockout mouse studies, Co-immunoprecipitation/direct interaction assays, patch-clamp electrophysiology, super-resolution microscopy of CatSper nanodomains","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (KO phenotype, direct binding assay, electrophysiology, nanodomain imaging) in a single rigorous study","pmids":["31056283"],"is_preprint":false},{"year":2019,"finding":"Loss of EFCAB9 in knockout mice abolishes pH-dependent and Ca2+-sensitive activation of the CatSper channel and disrupts the linear arrangement of Ca2+ signaling nanodomains, resulting in compromised sperm motility and male subfertility.","method":"Knockout mouse model, sperm motility analysis, electrophysiology (CatSper currents), super-resolution fluorescence imaging","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular and channel-level phenotypes, multiple orthogonal readouts in one study","pmids":["31056283"],"is_preprint":false},{"year":2021,"finding":"A conserved IQ-like motif in CATSPERζ is required for its interaction with EFCAB9, and recombinant opossum EFCAB9 can interact with mouse CATSPERζ despite high sequence divergence, indicating evolutionary conservation of this pH-tuned Ca2+ sensor–channel subunit interaction.","method":"Recombinant protein interaction assays, sequence/motif analysis, cross-species binding experiments","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — direct binding assay with defined motif requirement across species, single lab","pmids":["33946695"],"is_preprint":false},{"year":2022,"finding":"EFCAB9 interacts with C2CD6, a newly identified CatSper subunit containing a calcium-dependent C2 domain; this interaction places EFCAB9 within an extended CatSper complex whose integrity is required for proper nanodomain organization on the flagellar membrane.","method":"Co-immunoprecipitation, immunofluorescence, genetic KO of C2CD6 showing depletion of CatSper nanodomains","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — Co-IP showing EFCAB9–C2CD6 interaction and KO phenotype, single lab, two orthogonal methods","pmids":["34919125"],"is_preprint":false},{"year":2022,"finding":"CatSper-mediated Ca2+ influx regulated by EFCAB9 controls the clockwise swim-path chirality of sperm; loss of EFCAB9 abolishes this chirality, as does pharmacological CatSper inhibition, establishing EFCAB9 as necessary for this motility parameter.","method":"EFCAB9 knockout mouse sperm tracking, pharmacological CatSper inhibition (mibefradil, NNC 55-0396), zona pellucida ZP2 N-terminal fragment stimulation","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO phenotype with pharmacological validation, single lab, two complementary approaches","pmids":["35438819"],"is_preprint":false},{"year":2025,"finding":"EFCAB9 forms a cytosolic ternary subcomplex with ARMH2 and CATSPERζ within the CatSper channel, contributing to stable linear nanodomain assembly along the sperm tail and to pH/Ca2+ sensitivity of the channel; this was revealed by cryo-EM structural analysis combined with mass spectrometry.","method":"Cryo-EM structure determination, mass spectrometry, AlphaFold prediction, coevolutionary analysis, ARMH2 knockout mouse showing disrupted CatSper nanodomains and subfertility","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structural evidence plus mass spectrometry and KO functional validation in a single rigorous study","pmids":["41271765"],"is_preprint":false}],"current_model":"EFCAB9 is a cytoplasmic EF-hand Ca2+-binding protein that functions as a dual pH/Ca2+ sensor within the CatSper sperm calcium channel complex: it directly binds CATSPERζ via a conserved IQ-like motif in a Ca2+-dependent, pH-sensitive manner, forms a ternary subcomplex with CATSPERζ and ARMH2 as revealed by cryo-EM, and is required for pH-dependent and Ca2+-sensitive CatSper channel activation, linear organization of CatSper Ca2+ signaling nanodomains along the sperm flagellum, sperm hyperactivated motility, swim-path chirality, and male fertility."},"narrative":{"mechanistic_narrative":"EFCAB9 is a cytoplasmic, bifunctional EF-hand Ca2+ sensor that serves as a pH and Ca2+ tuning element of the sperm CatSper calcium channel and is required for hyperactivated sperm motility and male fertility [PMID:31056283]. It binds the CatSper subunit CATSPERζ directly through a conserved IQ-like motif in a Ca2+-dependent, pH-sensitive manner, dissociating at elevated pH, and this interaction is evolutionarily conserved across divergent species [PMID:31056283, PMID:33946695]. Structurally, EFCAB9 assembles with CATSPERζ and ARMH2 into a cytosolic ternary subcomplex resolved by cryo-EM, and it further associates with the C2-domain subunit C2CD6, integrating it into the extended CatSper complex [PMID:34919125, PMID:41271765]. Through these interactions EFCAB9 enables pH-dependent and Ca2+-sensitive CatSper channel activation and the stable linear organization of CatSper Ca2+ signaling nanodomains along the flagellum; its loss abolishes channel gating, disrupts nanodomain arrangement, and eliminates the clockwise swim-path chirality of sperm [PMID:31056283, PMID:35438819, PMID:41271765].","teleology":[{"year":2019,"claim":"Established EFCAB9 as a bifunctional Ca2+ sensor physically coupled to the CatSper channel, answering how channel activity could be jointly tuned by intracellular Ca2+ and pH.","evidence":"Knockout mice, Co-IP/direct binding assays, patch-clamp electrophysiology, and super-resolution imaging of CatSper nanodomains","pmids":["31056283"],"confidence":"High","gaps":["Atomic-level structural basis of the Ca2+/pH switch not resolved","Stoichiometry within the channel complex undefined"]},{"year":2019,"claim":"Demonstrated that EFCAB9 is functionally required, linking its loss to abolished pH/Ca2+-dependent channel gating, disrupted nanodomains, and subfertility.","evidence":"Knockout mouse sperm motility analysis, CatSper current electrophysiology, super-resolution imaging","pmids":["31056283"],"confidence":"High","gaps":["Quantitative contribution of nanodomain disorganization versus channel gating to the motility defect not separated"]},{"year":2021,"claim":"Mapped the EFCAB9 binding determinant to a conserved IQ-like motif in CATSPERζ and showed cross-species interaction, defining the molecular interface and its evolutionary conservation.","evidence":"Recombinant protein interaction assays, motif/sequence analysis, cross-species (opossum/mouse) binding experiments","pmids":["33946695"],"confidence":"Medium","gaps":["Single lab; in vivo requirement of the IQ-like motif not tested by mutation","No structural model of the bound interface at this stage"]},{"year":2022,"claim":"Placed EFCAB9 within an extended CatSper complex by identifying its interaction with the C2-domain subunit C2CD6 required for nanodomain integrity.","evidence":"Co-immunoprecipitation, immunofluorescence, and C2CD6 knockout showing nanodomain depletion","pmids":["34919125"],"confidence":"Medium","gaps":["Direct versus indirect nature of EFCAB9-C2CD6 interaction not fully resolved","Single lab; reciprocal validation limited"]},{"year":2022,"claim":"Connected EFCAB9/CatSper Ca2+ signaling to a specific motility output, clockwise swim-path chirality, expanding the physiological role beyond bulk motility.","evidence":"EFCAB9 knockout sperm tracking with pharmacological CatSper inhibition and ZP2 fragment stimulation","pmids":["35438819"],"confidence":"Medium","gaps":["Mechanistic link between Ca2+ nanodomain geometry and chirality not defined","Single lab"]},{"year":2025,"claim":"Resolved the cytosolic ternary subcomplex of EFCAB9, ARMH2, and CATSPERζ, providing the structural framework for how EFCAB9 anchors and tunes the channel.","evidence":"Cryo-EM structure, mass spectrometry, AlphaFold/coevolutionary analysis, and ARMH2 knockout mouse with disrupted nanodomains and subfertility","pmids":["41271765"],"confidence":"High","gaps":["Conformational basis of the pH/Ca2+ switch within the resolved structure not fully described","Human relevance and fertility variants not addressed"]},{"year":null,"claim":"How EF-hand Ca2+ occupancy and protonation are mechanistically transduced into channel gating and nanodomain assembly remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No dynamic structural model coupling Ca2+/pH state to gating","Human physiological and clinical role uncharacterized in the corpus"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140299","term_label":"molecular sensor activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,5]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,5]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[1,4]}],"complexes":["CatSper channel complex","EFCAB9-ARMH2-CATSPERζ ternary subcomplex"],"partners":["CATSPERZ","ARMH2","C2CD6"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"A8MZ26","full_name":"EF-hand calcium-binding domain-containing protein 9","aliases":[],"length_aa":197,"mass_kda":23.9,"function":"Auxiliary component of the CatSper complex, a complex involved in sperm cell hyperactivation. pH-dependent Ca(2+) sensor required to activate the CatSper channel. Sperm cell hyperactivation is needed for sperm motility which is essential late in the preparation of sperm for fertilization. Associates with the CatSper complex via direct interaction with CATSPERZ, and senses intracellular Ca(2+). Together with CATSPERZ, associates with the CatSper channel pore and is required for the two-row structure of each single CatSper channel","subcellular_location":"Cytoplasm; Cell projection, cilium, flagellum","url":"https://www.uniprot.org/uniprotkb/A8MZ26/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/EFCAB9","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/EFCAB9","total_profiled":1310},"omim":[{"mim_id":"619776","title":"C2 CALCIUM-DEPENDENT DOMAIN-CONTAINING PROTEIN 6; C2CD6","url":"https://www.omim.org/entry/619776"},{"mim_id":"618520","title":"EF-HAND CALCIUM-BINDING DOMAIN-CONTAINING PROTEIN 9; EFCAB9","url":"https://www.omim.org/entry/618520"},{"mim_id":"603209","title":"CYTIDINE MONOPHOSPHO-N-ACETYLNEURAMINIC ACID HYDROXYLASE, PSEUDOGENE; CMAHP","url":"https://www.omim.org/entry/603209"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in single","driving_tissues":[{"tissue":"testis","ntpm":9.5}],"url":"https://www.proteinatlas.org/search/EFCAB9"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"A8MZ26","domains":[{"cath_id":"1.10.238.10","chopping":"9-177","consensus_level":"medium","plddt":95.6196,"start":9,"end":177}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/A8MZ26","model_url":"https://alphafold.ebi.ac.uk/files/AF-A8MZ26-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-A8MZ26-F1-predicted_aligned_error_v6.png","plddt_mean":94.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=EFCAB9","jax_strain_url":"https://www.jax.org/strain/search?query=EFCAB9"},"sequence":{"accession":"A8MZ26","fasta_url":"https://rest.uniprot.org/uniprotkb/A8MZ26.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/A8MZ26/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/A8MZ26"}},"corpus_meta":[{"pmid":"31056283","id":"PMC_31056283","title":"Dual Sensing of Physiologic pH and Calcium by EFCAB9 Regulates Sperm Motility.","date":"2019","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/31056283","citation_count":129,"is_preprint":false},{"pmid":"34919125","id":"PMC_34919125","title":"C2CD6 regulates targeting and organization of the CatSper calcium channel complex in sperm flagella.","date":"2022","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/34919125","citation_count":24,"is_preprint":false},{"pmid":"33946695","id":"PMC_33946695","title":"Molecular Evolution of CatSper in Mammals and Function of Sperm Hyperactivation in Gray Short-Tailed Opossum.","date":"2021","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/33946695","citation_count":13,"is_preprint":false},{"pmid":"35438819","id":"PMC_35438819","title":"CatSper and its CaM-like Ca2+ sensor EFCAB9 are necessary for the path chirality of sperm.","date":"2022","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/35438819","citation_count":8,"is_preprint":false},{"pmid":"31447243","id":"PMC_31447243","title":"Tiny Dancer: EFCAB9 Triggers Sperm Hyperactivation via CatSper.","date":"2019","source":"Trends in biochemical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/31447243","citation_count":2,"is_preprint":false},{"pmid":"41271765","id":"PMC_41271765","title":"ARMH2 is a cytosolic component of CatSper crucial for sperm function.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/41271765","citation_count":2,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4669,"output_tokens":1525,"usd":0.018441,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8321,"output_tokens":2212,"usd":0.048453,"stage2_stop_reason":"end_turn"},"total_usd":0.066894,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2019,\n      \"finding\": \"EFCAB9 is a cytoplasmic, bifunctional Ca2+ sensor that directly interacts with CATSPERζ (a subunit of the CatSper channel) in a Ca2+-dependent manner and dissociates from it at elevated pH, thereby modulating both CatSper channel activity and the linear organization of CatSper Ca2+ signaling nanodomains along the sperm tail.\",\n      \"method\": \"Knockout mouse studies, Co-immunoprecipitation/direct interaction assays, patch-clamp electrophysiology, super-resolution microscopy of CatSper nanodomains\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (KO phenotype, direct binding assay, electrophysiology, nanodomain imaging) in a single rigorous study\",\n      \"pmids\": [\"31056283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Loss of EFCAB9 in knockout mice abolishes pH-dependent and Ca2+-sensitive activation of the CatSper channel and disrupts the linear arrangement of Ca2+ signaling nanodomains, resulting in compromised sperm motility and male subfertility.\",\n      \"method\": \"Knockout mouse model, sperm motility analysis, electrophysiology (CatSper currents), super-resolution fluorescence imaging\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular and channel-level phenotypes, multiple orthogonal readouts in one study\",\n      \"pmids\": [\"31056283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A conserved IQ-like motif in CATSPERζ is required for its interaction with EFCAB9, and recombinant opossum EFCAB9 can interact with mouse CATSPERζ despite high sequence divergence, indicating evolutionary conservation of this pH-tuned Ca2+ sensor–channel subunit interaction.\",\n      \"method\": \"Recombinant protein interaction assays, sequence/motif analysis, cross-species binding experiments\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — direct binding assay with defined motif requirement across species, single lab\",\n      \"pmids\": [\"33946695\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"EFCAB9 interacts with C2CD6, a newly identified CatSper subunit containing a calcium-dependent C2 domain; this interaction places EFCAB9 within an extended CatSper complex whose integrity is required for proper nanodomain organization on the flagellar membrane.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, genetic KO of C2CD6 showing depletion of CatSper nanodomains\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — Co-IP showing EFCAB9–C2CD6 interaction and KO phenotype, single lab, two orthogonal methods\",\n      \"pmids\": [\"34919125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CatSper-mediated Ca2+ influx regulated by EFCAB9 controls the clockwise swim-path chirality of sperm; loss of EFCAB9 abolishes this chirality, as does pharmacological CatSper inhibition, establishing EFCAB9 as necessary for this motility parameter.\",\n      \"method\": \"EFCAB9 knockout mouse sperm tracking, pharmacological CatSper inhibition (mibefradil, NNC 55-0396), zona pellucida ZP2 N-terminal fragment stimulation\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO phenotype with pharmacological validation, single lab, two complementary approaches\",\n      \"pmids\": [\"35438819\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"EFCAB9 forms a cytosolic ternary subcomplex with ARMH2 and CATSPERζ within the CatSper channel, contributing to stable linear nanodomain assembly along the sperm tail and to pH/Ca2+ sensitivity of the channel; this was revealed by cryo-EM structural analysis combined with mass spectrometry.\",\n      \"method\": \"Cryo-EM structure determination, mass spectrometry, AlphaFold prediction, coevolutionary analysis, ARMH2 knockout mouse showing disrupted CatSper nanodomains and subfertility\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structural evidence plus mass spectrometry and KO functional validation in a single rigorous study\",\n      \"pmids\": [\"41271765\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"EFCAB9 is a cytoplasmic EF-hand Ca2+-binding protein that functions as a dual pH/Ca2+ sensor within the CatSper sperm calcium channel complex: it directly binds CATSPERζ via a conserved IQ-like motif in a Ca2+-dependent, pH-sensitive manner, forms a ternary subcomplex with CATSPERζ and ARMH2 as revealed by cryo-EM, and is required for pH-dependent and Ca2+-sensitive CatSper channel activation, linear organization of CatSper Ca2+ signaling nanodomains along the sperm flagellum, sperm hyperactivated motility, swim-path chirality, and male fertility.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"EFCAB9 is a cytoplasmic, bifunctional EF-hand Ca2+ sensor that serves as a pH and Ca2+ tuning element of the sperm CatSper calcium channel and is required for hyperactivated sperm motility and male fertility [#0, #1]. It binds the CatSper subunit CATSPERζ directly through a conserved IQ-like motif in a Ca2+-dependent, pH-sensitive manner, dissociating at elevated pH, and this interaction is evolutionarily conserved across divergent species [#0, #2]. Structurally, EFCAB9 assembles with CATSPERζ and ARMH2 into a cytosolic ternary subcomplex resolved by cryo-EM, and it further associates with the C2-domain subunit C2CD6, integrating it into the extended CatSper complex [#3, #5]. Through these interactions EFCAB9 enables pH-dependent and Ca2+-sensitive CatSper channel activation and the stable linear organization of CatSper Ca2+ signaling nanodomains along the flagellum; its loss abolishes channel gating, disrupts nanodomain arrangement, and eliminates the clockwise swim-path chirality of sperm [#1, #4, #5].\",\n  \"teleology\": [\n    {\n      \"year\": 2019,\n      \"claim\": \"Established EFCAB9 as a bifunctional Ca2+ sensor physically coupled to the CatSper channel, answering how channel activity could be jointly tuned by intracellular Ca2+ and pH.\",\n      \"evidence\": \"Knockout mice, Co-IP/direct binding assays, patch-clamp electrophysiology, and super-resolution imaging of CatSper nanodomains\",\n      \"pmids\": [\"31056283\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-level structural basis of the Ca2+/pH switch not resolved\", \"Stoichiometry within the channel complex undefined\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrated that EFCAB9 is functionally required, linking its loss to abolished pH/Ca2+-dependent channel gating, disrupted nanodomains, and subfertility.\",\n      \"evidence\": \"Knockout mouse sperm motility analysis, CatSper current electrophysiology, super-resolution imaging\",\n      \"pmids\": [\"31056283\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of nanodomain disorganization versus channel gating to the motility defect not separated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Mapped the EFCAB9 binding determinant to a conserved IQ-like motif in CATSPERζ and showed cross-species interaction, defining the molecular interface and its evolutionary conservation.\",\n      \"evidence\": \"Recombinant protein interaction assays, motif/sequence analysis, cross-species (opossum/mouse) binding experiments\",\n      \"pmids\": [\"33946695\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab; in vivo requirement of the IQ-like motif not tested by mutation\", \"No structural model of the bound interface at this stage\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed EFCAB9 within an extended CatSper complex by identifying its interaction with the C2-domain subunit C2CD6 required for nanodomain integrity.\",\n      \"evidence\": \"Co-immunoprecipitation, immunofluorescence, and C2CD6 knockout showing nanodomain depletion\",\n      \"pmids\": [\"34919125\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct versus indirect nature of EFCAB9-C2CD6 interaction not fully resolved\", \"Single lab; reciprocal validation limited\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Connected EFCAB9/CatSper Ca2+ signaling to a specific motility output, clockwise swim-path chirality, expanding the physiological role beyond bulk motility.\",\n      \"evidence\": \"EFCAB9 knockout sperm tracking with pharmacological CatSper inhibition and ZP2 fragment stimulation\",\n      \"pmids\": [\"35438819\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between Ca2+ nanodomain geometry and chirality not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the cytosolic ternary subcomplex of EFCAB9, ARMH2, and CATSPERζ, providing the structural framework for how EFCAB9 anchors and tunes the channel.\",\n      \"evidence\": \"Cryo-EM structure, mass spectrometry, AlphaFold/coevolutionary analysis, and ARMH2 knockout mouse with disrupted nanodomains and subfertility\",\n      \"pmids\": [\"41271765\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Conformational basis of the pH/Ca2+ switch within the resolved structure not fully described\", \"Human relevance and fertility variants not addressed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How EF-hand Ca2+ occupancy and protonation are mechanistically transduced into channel gating and nanodomain assembly remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No dynamic structural model coupling Ca2+/pH state to gating\", \"Human physiological and clinical role uncharacterized in the corpus\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140299\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [1, 4]}\n    ],\n    \"complexes\": [\"CatSper channel complex\", \"EFCAB9-ARMH2-CATSPERζ ternary subcomplex\"],\n    \"partners\": [\"CATSPERZ\", \"ARMH2\", \"C2CD6\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}