{"gene":"KIF9","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":2001,"finding":"KIF9 was identified as a binding partner of the Ras-like GTPase Gem (RGK family) via yeast two-hybrid screen, and their interaction was confirmed by co-immunoprecipitation, representing the first molecular link between RGK family GTPases and the microtubule cytoskeleton.","method":"Yeast two-hybrid screen; co-immunoprecipitation","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — reciprocal Co-IP confirming yeast two-hybrid result, single lab, two orthogonal methods","pmids":["11483511"],"is_preprint":false},{"year":2010,"finding":"KIF9 regulates podosome number and matrix degradation in primary human macrophages; siRNA/shRNA knockdown significantly impairs both podosome numbers and matrix lysis. The unique C-terminal region of KIF9 is required for these effects and mediates binding to reggie-1/flotillin-2, a signaling mediator between intracellular vesicles and the cell periphery, as shown by co-immunoprecipitation and colocalization.","method":"siRNA/shRNA knockdown; overexpression; microinjection; co-immunoprecipitation; live-cell imaging","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockdown with defined cellular phenotype plus Co-IP of interactor, single lab, multiple orthogonal methods","pmids":["21119006"],"is_preprint":false},{"year":2012,"finding":"KIF9 is a downstream effector of Gem in mitosis: siRNA depletion of KIF9 phenocopies Gem loss, causing spindle elongation, increased microtubule polymerization rates, and chromosome misalignment. KIF9 depletion increases steady-state spindle α-tubulin levels by increasing microtubule polymerization, establishing KIF9 as a regulator of spindle dynamics and length.","method":"siRNA knockdown; spindle length measurement; tubulin polymerization analysis; epistasis (Gem/KIF9 double depletion)","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with defined spindle phenotype, single lab, multiple quantitative readouts","pmids":["22964304"],"is_preprint":false},{"year":2020,"finding":"KIF9 is required for progressive sperm motility in mice; CRISPR/Cas9-generated Kif9 mutant mice display impaired sperm motility, asymmetric flagellar waveform, and circular sperm motion leading to subfertility. Immunofluorescence and immunoblot showed KIF9 is absent from spermatozoa lacking the central pair protein HYDIN, indicating KIF9 associates with central pair microtubules of the axoneme to regulate flagellar motility.","method":"CRISPR/Cas9 knockout mouse; sperm motility analysis; immunofluorescence; immunoblot; epistasis with HYDIN mutant","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined motility phenotype, epistasis with central pair component, two orthogonal detection methods, replicated in human data (PMID:36686457)","pmids":["32072696"],"is_preprint":false},{"year":2023,"finding":"Bi-allelic loss-of-function KIF9 variants in human patients cause asthenozoospermia. Co-immunoprecipitation in human samples confirmed KIF9 interacts with the central pair microtubule component HYDIN. Immunofluorescence showed KIF9 localizes throughout sperm flagella and is absent in spermatozoa with central pair deletions, consistent with KIF9 functioning at the central pair to regulate flagellar beating.","method":"Whole exome sequencing; co-immunoprecipitation; immunofluorescence; transmission electron microscopy; western blot","journal":"Frontiers in endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP of HYDIN interaction in human samples, localization data, single lab but consistent with mouse KO data","pmids":["36686457"],"is_preprint":false},{"year":2025,"finding":"KIF9 promotes macroautophagy in neurons by mediating anterograde transport of lysosomes via kinesin light chain 1 (KLC1). Loss of KIF9 impairs lysosomal transport and macroautophagy, increasing amyloidogenic APP processing and Aβ accumulation. AAV-mediated KIF9 upregulation in APP23/PS45 AD mice reduced Aβ deposition and improved cognitive function by restoring macroautophagy.","method":"Co-immunoprecipitation (KIF9-KLC1); AAV-mediated overexpression in vivo; live lysosome transport assay; immunofluorescence; behavioral tests; western blot","journal":"Aging cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KLC1 interaction confirmed by Co-IP, lysosome transport and autophagy rescue in vivo, single lab with multiple orthogonal methods","pmids":["39829171"],"is_preprint":false},{"year":2025,"finding":"KIF9 is a plus-end-directed kinesin motor that localizes to centriolar satellites during interphase and regulates their pericentrosomal positioning. Loss of KIF9 causes centriolar satellite aggregation closer to the centrosome, increased centrosomal protein degradation, impaired centrosome maturation, and consequent chromosome congression and segregation defects during mitosis.","method":"KIF9 knockdown/knockout; live-cell imaging; immunofluorescence; proteomic analysis (mass spectrometry); centrosome maturation assays; mitotic phenotype quantification","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct localization with functional consequence, KO phenotype with defined molecular mechanism (satellite misposition → protein degradation → spindle defects), peer-reviewed and consistent with preprint version","pmids":["40975050"],"is_preprint":false},{"year":2024,"finding":"KIF9 loss causes centriolar satellite aggregation near the centrosome and increased centrosomal protein degradation that disrupts centrosome maturation, resulting in chromosome congression and segregation defects during mitosis — establishing roles for Kif9 and centriolar satellites in cellular proteostasis and mitosis. (Preprint version of PMID:40975050.)","method":"KIF9 knockdown/knockout; live-cell imaging; immunofluorescence; proteomic analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — preprint, same data as peer-reviewed version; included for completeness but superseded by published paper","pmids":["38617353"],"is_preprint":true},{"year":2025,"finding":"KIF9 loss causes centriolar satellite (CS) aggregation near the centrosome, leading to defects in primary cilia length and altered levels of key cilia proteins TALPID3, CEP131, CEP170, and CEP290, linking KIF9-regulated satellite positioning to primary cilia assembly and maintenance.","method":"KIF9 loss-of-function; immunofluorescence; cilia length measurement; western blot for cilia proteins","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined molecular phenotype (satellite aggregation → cilia defects with specific protein changes), single lab","pmids":["40879105"],"is_preprint":false}],"current_model":"KIF9 is a plus-end-directed kinesin motor that functions at multiple microtubule-associated structures: it interacts with the Gem GTPase to regulate mitotic spindle length and chromosome segregation; localizes to centriolar satellites to control their pericentrosomal positioning, centrosome maturation, and primary cilia length; associates with central pair microtubules in flagella (via HYDIN) to regulate sperm motility; interacts with reggie-1/flotillin-2 through its C-terminal region to enable macrophage podosome matrix degradation; and promotes macroautophagy by mediating anterograde lysosomal transport via kinesin light chain 1 (KLC1)."},"narrative":{"mechanistic_narrative":"KIF9 is a plus-end-directed kinesin motor that operates at multiple microtubule-associated structures to control cell division, ciliary and flagellar function, and intracellular transport [PMID:40975050]. In mitosis, KIF9 acts downstream of the RGK GTPase Gem, with which it physically interacts, to restrain microtubule polymerization and thereby set spindle length and ensure proper chromosome alignment [PMID:11483511, PMID:22964304]. During interphase, KIF9 localizes to centriolar satellites and governs their pericentrosomal positioning; its loss causes satellite aggregation near the centrosome, increased degradation of centrosomal proteins, impaired centrosome maturation, and downstream chromosome congression and segregation defects [PMID:40975050], and this same satellite-positioning function supports primary cilium length and the maintenance of cilia proteins including TALPID3, CEP131, CEP170, and CEP290 [PMID:40879105]. In the flagellar axoneme, KIF9 associates with central pair microtubules through the central pair component HYDIN to drive symmetric flagellar waveform and progressive sperm motility; loss-of-function abolishes KIF9 from sperm lacking HYDIN and produces asthenozoospermia in mice and humans [PMID:32072696, PMID:36686457]. KIF9 additionally mediates anterograde lysosomal transport via kinesin light chain 1 (KLC1) to promote macroautophagy [PMID:39829171] and supports macrophage podosome matrix degradation through a C-terminal interaction with reggie-1/flotillin-2 [PMID:21119006].","teleology":[{"year":2001,"claim":"Established the first molecular link between an RGK-family GTPase and the microtubule motor machinery by identifying KIF9 as a Gem-binding partner, raising the question of what cytoskeletal process this interaction serves.","evidence":"Yeast two-hybrid screen with reciprocal co-immunoprecipitation","pmids":["11483511"],"confidence":"Medium","gaps":["Did not define the functional consequence of the Gem-KIF9 interaction","No motor activity or directionality demonstrated","Single lab"]},{"year":2010,"claim":"Showed KIF9 has a cytoskeletal-remodeling role beyond mitosis by linking its C-terminal region to podosome formation and matrix degradation in macrophages.","evidence":"siRNA/shRNA knockdown, overexpression, microinjection, and co-IP/colocalization with reggie-1/flotillin-2 in primary human macrophages","pmids":["21119006"],"confidence":"Medium","gaps":["Mechanism by which flotillin-2 binding controls podosome activity unresolved","Cargo transported by KIF9 in this context not identified","Single lab"]},{"year":2012,"claim":"Resolved the functional meaning of the Gem-KIF9 interaction, placing KIF9 as a downstream effector of Gem that limits microtubule polymerization to control spindle length and chromosome alignment.","evidence":"siRNA depletion with spindle length and tubulin polymerization measurements and Gem/KIF9 epistasis","pmids":["22964304"],"confidence":"Medium","gaps":["Did not determine whether KIF9 restrains polymerization directly via motor activity or indirectly","No structural basis for the Gem-KIF9 interaction","Single lab"]},{"year":2020,"claim":"Identified an axonemal role for KIF9 by showing it is required for progressive sperm motility and depends on the central pair component HYDIN for its localization.","evidence":"CRISPR/Cas9 knockout mouse with sperm motility analysis, immunofluorescence/immunoblot, and epistasis with HYDIN mutant","pmids":["32072696"],"confidence":"High","gaps":["Did not define how KIF9 motor activity shapes the flagellar waveform","Direct binding partner within the central pair not pinpointed"]},{"year":2023,"claim":"Extended the flagellar role to human disease, establishing bi-allelic KIF9 loss-of-function as a cause of asthenozoospermia and confirming the KIF9-HYDIN interaction in human samples.","evidence":"Whole exome sequencing of patients, co-IP, immunofluorescence, and transmission electron microscopy","pmids":["36686457"],"confidence":"Medium","gaps":["Did not establish the structural mechanism of KIF9 at the central pair","Patient cohort limited","Single lab"]},{"year":2025,"claim":"Defined KIF9 as a centriolar satellite regulator, showing satellite mispositioning upon its loss drives centrosomal protein degradation, impaired centrosome maturation, and mitotic chromosome defects.","evidence":"KIF9 knockdown/knockout with live-cell imaging, immunofluorescence, mass spectrometry proteomics, and centrosome maturation assays","pmids":["40975050"],"confidence":"High","gaps":["Cargo and adaptors linking KIF9 to satellites not fully mapped","Relationship between satellite-positioning and the Gem-dependent spindle role not integrated"]},{"year":2025,"claim":"Connected KIF9-controlled satellite positioning to ciliogenesis, showing its loss alters primary cilia length and levels of specific cilia proteins.","evidence":"KIF9 loss-of-function with cilia length measurement and western blot for TALPID3, CEP131, CEP170, CEP290","pmids":["40879105"],"confidence":"Medium","gaps":["Did not establish whether the cilia protein changes are direct or secondary to satellite aggregation","Single lab"]},{"year":2025,"claim":"Demonstrated a transport-and-clearance role for KIF9, showing it drives anterograde lysosomal transport via KLC1 to sustain macroautophagy, with therapeutic relevance in an Alzheimer's model.","evidence":"KIF9-KLC1 co-IP, live lysosome transport assay, and AAV-mediated overexpression with behavioral testing in APP23/PS45 mice","pmids":["39829171"],"confidence":"Medium","gaps":["Did not establish whether KIF9 acts as a primary motor or accessory adaptor in lysosome transport","Generalizability beyond neurons unclear","Single lab"]},{"year":null,"claim":"How KIF9's distinct activities across spindle, centriolar satellites, axonemal central pair, podosomes, and lysosomal transport are coordinated and selected in different cell types remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying model linking motor directionality to its diverse cargoes","No structural characterization of KIF9 motor or cargo-binding regions","Cargo-selection mechanism unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003774","term_label":"cytoskeletal motor activity","supporting_discovery_ids":[6]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[2,6]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[6,8]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[2,3,6]},{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[8]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[5]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[6,8]}],"complexes":[],"partners":["GEM","HYDIN","KLC1","FLOT2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9HAQ2","full_name":"Kinesin-like protein KIF9","aliases":[],"length_aa":790,"mass_kda":90.0,"function":"Essential for normal male fertility and for progressive motility of spermatozoa","subcellular_location":"Cytoplasm, cytoskeleton; Cell projection, cilium, flagellum; Cytoplasm, cytoskeleton, flagellum axoneme","url":"https://www.uniprot.org/uniprotkb/Q9HAQ2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KIF9","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KIF9","total_profiled":1310},"omim":[{"mim_id":"607910","title":"KINESIN FAMILY MEMBER 9; KIF9","url":"https://www.omim.org/entry/607910"},{"mim_id":"600164","title":"GTP-BINDING MITOGEN-INDUCED T-CELL PROTEIN; GEM","url":"https://www.omim.org/entry/600164"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Primary cilium","reliability":"Approved"},{"location":"Primary cilium tip","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"},{"location":"Mid piece","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"choroid plexus","ntpm":107.2},{"tissue":"testis","ntpm":60.4}],"url":"https://www.proteinatlas.org/search/KIF9"},"hgnc":{"alias_symbol":["MGC104186"],"prev_symbol":[]},"alphafold":{"accession":"Q9HAQ2","domains":[{"cath_id":"3.40.850.10","chopping":"6-40_50-157_167-351","consensus_level":"high","plddt":88.0064,"start":6,"end":351},{"cath_id":"-","chopping":"356-449","consensus_level":"medium","plddt":84.5067,"start":356,"end":449},{"cath_id":"1.10.287","chopping":"578-731","consensus_level":"high","plddt":79.1169,"start":578,"end":731},{"cath_id":"1.20.5","chopping":"745-790","consensus_level":"high","plddt":62.7711,"start":745,"end":790}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HAQ2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HAQ2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HAQ2-F1-predicted_aligned_error_v6.png","plddt_mean":74.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KIF9","jax_strain_url":"https://www.jax.org/strain/search?query=KIF9"},"sequence":{"accession":"Q9HAQ2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9HAQ2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9HAQ2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HAQ2"}},"corpus_meta":[{"pmid":"11483511","id":"PMC_11483511","title":"The Ras-like GTPase Gem is involved in cell shape remodelling and interacts with the novel kinesin-like protein KIF9.","date":"2001","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/11483511","citation_count":70,"is_preprint":false},{"pmid":"29207070","id":"PMC_29207070","title":"KIF9‑AS1, LINC01272 and DIO3OS lncRNAs as novel biomarkers for inflammatory bowel disease.","date":"2017","source":"Molecular medicine reports","url":"https://pubmed.ncbi.nlm.nih.gov/29207070","citation_count":60,"is_preprint":false},{"pmid":"21119006","id":"PMC_21119006","title":"The kinesin KIF9 and reggie/flotillin proteins regulate matrix degradation by macrophage podosomes.","date":"2010","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/21119006","citation_count":50,"is_preprint":false},{"pmid":"32072696","id":"PMC_32072696","title":"Testis-enriched kinesin KIF9 is important for progressive motility in mouse spermatozoa.","date":"2020","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/32072696","citation_count":38,"is_preprint":false},{"pmid":"32343913","id":"PMC_32343913","title":"Long Noncoding RNA KIF9-AS1 Regulates Transforming Growth Factor-β and Autophagy Signaling to Enhance Renal Cell Carcinoma Chemoresistance via microRNA-497-5p.","date":"2020","source":"DNA and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/32343913","citation_count":34,"is_preprint":false},{"pmid":"22964304","id":"PMC_22964304","title":"The GTPase Gem and its partner Kif9 are required for chromosome alignment, spindle length control, and mitotic progression.","date":"2012","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/22964304","citation_count":17,"is_preprint":false},{"pmid":"34750325","id":"PMC_34750325","title":"Long noncoding RNA KIF9-AS1 promotes cell apoptosis by targeting the microRNA-148a-3p/suppressor of cytokine signaling axis in inflammatory bowel disease.","date":"2021","source":"European journal of gastroenterology & hepatology","url":"https://pubmed.ncbi.nlm.nih.gov/34750325","citation_count":14,"is_preprint":false},{"pmid":"36276278","id":"PMC_36276278","title":"The lncRNA KIF9-AS1 Accelerates Hepatocellular Carcinoma Growth by Recruiting DNMT1 to Promote RAI2 DNA Methylation.","date":"2022","source":"Journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36276278","citation_count":11,"is_preprint":false},{"pmid":"36686457","id":"PMC_36686457","title":"Identification of bi-allelic KIF9 loss-of-function variants contributing to asthenospermia and male infertility in two Chinese families.","date":"2023","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/36686457","citation_count":8,"is_preprint":false},{"pmid":"39735272","id":"PMC_39735272","title":"N6-methyladenosine-modified long non-coding RNA KIF9-AS1 promotes stemness and sorafenib resistance in hepatocellular carcinoma by upregulating SHOX2 expression.","date":"2024","source":"World journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/39735272","citation_count":6,"is_preprint":false},{"pmid":"32973955","id":"PMC_32973955","title":"KIF9-AS1 promotes nasopharyngeal carcinoma progression by suppressing miR-16.","date":"2020","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/32973955","citation_count":4,"is_preprint":false},{"pmid":"39829171","id":"PMC_39829171","title":"KIF9 Ameliorates Neuropathology and Cognitive Dysfunction by Promoting Macroautophagy in a Mouse Model of Alzheimer's Disease.","date":"2025","source":"Aging cell","url":"https://pubmed.ncbi.nlm.nih.gov/39829171","citation_count":2,"is_preprint":false},{"pmid":"40975050","id":"PMC_40975050","title":"The kinesin motor Kif9 regulates centriolar satellite positioning during interphase.","date":"2025","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/40975050","citation_count":1,"is_preprint":false},{"pmid":"38617353","id":"PMC_38617353","title":"The kinesin motor Kif9 regulates centriolar satellite positioning and mitotic progression.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/38617353","citation_count":1,"is_preprint":false},{"pmid":"40879105","id":"PMC_40879105","title":"The Kinesin Motor Kif9 Disrupts Primary Cilia Length by Mispositioning Centriolar Satellites.","date":"2025","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/40879105","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9318,"output_tokens":2375,"usd":0.031789,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9505,"output_tokens":2944,"usd":0.060562,"stage2_stop_reason":"end_turn"},"total_usd":0.092351,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2001,\n      \"finding\": \"KIF9 was identified as a binding partner of the Ras-like GTPase Gem (RGK family) via yeast two-hybrid screen, and their interaction was confirmed by co-immunoprecipitation, representing the first molecular link between RGK family GTPases and the microtubule cytoskeleton.\",\n      \"method\": \"Yeast two-hybrid screen; co-immunoprecipitation\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — reciprocal Co-IP confirming yeast two-hybrid result, single lab, two orthogonal methods\",\n      \"pmids\": [\"11483511\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"KIF9 regulates podosome number and matrix degradation in primary human macrophages; siRNA/shRNA knockdown significantly impairs both podosome numbers and matrix lysis. The unique C-terminal region of KIF9 is required for these effects and mediates binding to reggie-1/flotillin-2, a signaling mediator between intracellular vesicles and the cell periphery, as shown by co-immunoprecipitation and colocalization.\",\n      \"method\": \"siRNA/shRNA knockdown; overexpression; microinjection; co-immunoprecipitation; live-cell imaging\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockdown with defined cellular phenotype plus Co-IP of interactor, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"21119006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"KIF9 is a downstream effector of Gem in mitosis: siRNA depletion of KIF9 phenocopies Gem loss, causing spindle elongation, increased microtubule polymerization rates, and chromosome misalignment. KIF9 depletion increases steady-state spindle α-tubulin levels by increasing microtubule polymerization, establishing KIF9 as a regulator of spindle dynamics and length.\",\n      \"method\": \"siRNA knockdown; spindle length measurement; tubulin polymerization analysis; epistasis (Gem/KIF9 double depletion)\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with defined spindle phenotype, single lab, multiple quantitative readouts\",\n      \"pmids\": [\"22964304\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"KIF9 is required for progressive sperm motility in mice; CRISPR/Cas9-generated Kif9 mutant mice display impaired sperm motility, asymmetric flagellar waveform, and circular sperm motion leading to subfertility. Immunofluorescence and immunoblot showed KIF9 is absent from spermatozoa lacking the central pair protein HYDIN, indicating KIF9 associates with central pair microtubules of the axoneme to regulate flagellar motility.\",\n      \"method\": \"CRISPR/Cas9 knockout mouse; sperm motility analysis; immunofluorescence; immunoblot; epistasis with HYDIN mutant\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined motility phenotype, epistasis with central pair component, two orthogonal detection methods, replicated in human data (PMID:36686457)\",\n      \"pmids\": [\"32072696\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Bi-allelic loss-of-function KIF9 variants in human patients cause asthenozoospermia. Co-immunoprecipitation in human samples confirmed KIF9 interacts with the central pair microtubule component HYDIN. Immunofluorescence showed KIF9 localizes throughout sperm flagella and is absent in spermatozoa with central pair deletions, consistent with KIF9 functioning at the central pair to regulate flagellar beating.\",\n      \"method\": \"Whole exome sequencing; co-immunoprecipitation; immunofluorescence; transmission electron microscopy; western blot\",\n      \"journal\": \"Frontiers in endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP of HYDIN interaction in human samples, localization data, single lab but consistent with mouse KO data\",\n      \"pmids\": [\"36686457\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KIF9 promotes macroautophagy in neurons by mediating anterograde transport of lysosomes via kinesin light chain 1 (KLC1). Loss of KIF9 impairs lysosomal transport and macroautophagy, increasing amyloidogenic APP processing and Aβ accumulation. AAV-mediated KIF9 upregulation in APP23/PS45 AD mice reduced Aβ deposition and improved cognitive function by restoring macroautophagy.\",\n      \"method\": \"Co-immunoprecipitation (KIF9-KLC1); AAV-mediated overexpression in vivo; live lysosome transport assay; immunofluorescence; behavioral tests; western blot\",\n      \"journal\": \"Aging cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KLC1 interaction confirmed by Co-IP, lysosome transport and autophagy rescue in vivo, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"39829171\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KIF9 is a plus-end-directed kinesin motor that localizes to centriolar satellites during interphase and regulates their pericentrosomal positioning. Loss of KIF9 causes centriolar satellite aggregation closer to the centrosome, increased centrosomal protein degradation, impaired centrosome maturation, and consequent chromosome congression and segregation defects during mitosis.\",\n      \"method\": \"KIF9 knockdown/knockout; live-cell imaging; immunofluorescence; proteomic analysis (mass spectrometry); centrosome maturation assays; mitotic phenotype quantification\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct localization with functional consequence, KO phenotype with defined molecular mechanism (satellite misposition → protein degradation → spindle defects), peer-reviewed and consistent with preprint version\",\n      \"pmids\": [\"40975050\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"KIF9 loss causes centriolar satellite aggregation near the centrosome and increased centrosomal protein degradation that disrupts centrosome maturation, resulting in chromosome congression and segregation defects during mitosis — establishing roles for Kif9 and centriolar satellites in cellular proteostasis and mitosis. (Preprint version of PMID:40975050.)\",\n      \"method\": \"KIF9 knockdown/knockout; live-cell imaging; immunofluorescence; proteomic analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — preprint, same data as peer-reviewed version; included for completeness but superseded by published paper\",\n      \"pmids\": [\"38617353\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KIF9 loss causes centriolar satellite (CS) aggregation near the centrosome, leading to defects in primary cilia length and altered levels of key cilia proteins TALPID3, CEP131, CEP170, and CEP290, linking KIF9-regulated satellite positioning to primary cilia assembly and maintenance.\",\n      \"method\": \"KIF9 loss-of-function; immunofluorescence; cilia length measurement; western blot for cilia proteins\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined molecular phenotype (satellite aggregation → cilia defects with specific protein changes), single lab\",\n      \"pmids\": [\"40879105\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"KIF9 is a plus-end-directed kinesin motor that functions at multiple microtubule-associated structures: it interacts with the Gem GTPase to regulate mitotic spindle length and chromosome segregation; localizes to centriolar satellites to control their pericentrosomal positioning, centrosome maturation, and primary cilia length; associates with central pair microtubules in flagella (via HYDIN) to regulate sperm motility; interacts with reggie-1/flotillin-2 through its C-terminal region to enable macrophage podosome matrix degradation; and promotes macroautophagy by mediating anterograde lysosomal transport via kinesin light chain 1 (KLC1).\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KIF9 is a plus-end-directed kinesin motor that operates at multiple microtubule-associated structures to control cell division, ciliary and flagellar function, and intracellular transport [#6]. In mitosis, KIF9 acts downstream of the RGK GTPase Gem, with which it physically interacts, to restrain microtubule polymerization and thereby set spindle length and ensure proper chromosome alignment [#0, #2]. During interphase, KIF9 localizes to centriolar satellites and governs their pericentrosomal positioning; its loss causes satellite aggregation near the centrosome, increased degradation of centrosomal proteins, impaired centrosome maturation, and downstream chromosome congression and segregation defects [#6], and this same satellite-positioning function supports primary cilium length and the maintenance of cilia proteins including TALPID3, CEP131, CEP170, and CEP290 [#8]. In the flagellar axoneme, KIF9 associates with central pair microtubules through the central pair component HYDIN to drive symmetric flagellar waveform and progressive sperm motility; loss-of-function abolishes KIF9 from sperm lacking HYDIN and produces asthenozoospermia in mice and humans [#3, #4]. KIF9 additionally mediates anterograde lysosomal transport via kinesin light chain 1 (KLC1) to promote macroautophagy [#5] and supports macrophage podosome matrix degradation through a C-terminal interaction with reggie-1/flotillin-2 [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established the first molecular link between an RGK-family GTPase and the microtubule motor machinery by identifying KIF9 as a Gem-binding partner, raising the question of what cytoskeletal process this interaction serves.\",\n      \"evidence\": \"Yeast two-hybrid screen with reciprocal co-immunoprecipitation\",\n      \"pmids\": [\"11483511\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define the functional consequence of the Gem-KIF9 interaction\", \"No motor activity or directionality demonstrated\", \"Single lab\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showed KIF9 has a cytoskeletal-remodeling role beyond mitosis by linking its C-terminal region to podosome formation and matrix degradation in macrophages.\",\n      \"evidence\": \"siRNA/shRNA knockdown, overexpression, microinjection, and co-IP/colocalization with reggie-1/flotillin-2 in primary human macrophages\",\n      \"pmids\": [\"21119006\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which flotillin-2 binding controls podosome activity unresolved\", \"Cargo transported by KIF9 in this context not identified\", \"Single lab\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Resolved the functional meaning of the Gem-KIF9 interaction, placing KIF9 as a downstream effector of Gem that limits microtubule polymerization to control spindle length and chromosome alignment.\",\n      \"evidence\": \"siRNA depletion with spindle length and tubulin polymerization measurements and Gem/KIF9 epistasis\",\n      \"pmids\": [\"22964304\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not determine whether KIF9 restrains polymerization directly via motor activity or indirectly\", \"No structural basis for the Gem-KIF9 interaction\", \"Single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified an axonemal role for KIF9 by showing it is required for progressive sperm motility and depends on the central pair component HYDIN for its localization.\",\n      \"evidence\": \"CRISPR/Cas9 knockout mouse with sperm motility analysis, immunofluorescence/immunoblot, and epistasis with HYDIN mutant\",\n      \"pmids\": [\"32072696\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define how KIF9 motor activity shapes the flagellar waveform\", \"Direct binding partner within the central pair not pinpointed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended the flagellar role to human disease, establishing bi-allelic KIF9 loss-of-function as a cause of asthenozoospermia and confirming the KIF9-HYDIN interaction in human samples.\",\n      \"evidence\": \"Whole exome sequencing of patients, co-IP, immunofluorescence, and transmission electron microscopy\",\n      \"pmids\": [\"36686457\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not establish the structural mechanism of KIF9 at the central pair\", \"Patient cohort limited\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined KIF9 as a centriolar satellite regulator, showing satellite mispositioning upon its loss drives centrosomal protein degradation, impaired centrosome maturation, and mitotic chromosome defects.\",\n      \"evidence\": \"KIF9 knockdown/knockout with live-cell imaging, immunofluorescence, mass spectrometry proteomics, and centrosome maturation assays\",\n      \"pmids\": [\"40975050\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cargo and adaptors linking KIF9 to satellites not fully mapped\", \"Relationship between satellite-positioning and the Gem-dependent spindle role not integrated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected KIF9-controlled satellite positioning to ciliogenesis, showing its loss alters primary cilia length and levels of specific cilia proteins.\",\n      \"evidence\": \"KIF9 loss-of-function with cilia length measurement and western blot for TALPID3, CEP131, CEP170, CEP290\",\n      \"pmids\": [\"40879105\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not establish whether the cilia protein changes are direct or secondary to satellite aggregation\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrated a transport-and-clearance role for KIF9, showing it drives anterograde lysosomal transport via KLC1 to sustain macroautophagy, with therapeutic relevance in an Alzheimer's model.\",\n      \"evidence\": \"KIF9-KLC1 co-IP, live lysosome transport assay, and AAV-mediated overexpression with behavioral testing in APP23/PS45 mice\",\n      \"pmids\": [\"39829171\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not establish whether KIF9 acts as a primary motor or accessory adaptor in lysosome transport\", \"Generalizability beyond neurons unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How KIF9's distinct activities across spindle, centriolar satellites, axonemal central pair, podosomes, and lysosomal transport are coordinated and selected in different cell types remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying model linking motor directionality to its diverse cargoes\", \"No structural characterization of KIF9 motor or cargo-binding regions\", \"Cargo-selection mechanism unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003774\", \"supporting_discovery_ids\": [6]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [2, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [6, 8]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [2, 3, 6]},\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [6, 8]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"GEM\", \"HYDIN\", \"KLC1\", \"FLOT2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}