{"gene":"IQUB","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":2011,"finding":"siRNA knockdown of Iqub in vertebrate cell lines results in elongated cilia, establishing a role for IQUB in regulating cilia length.","method":"siRNA knockdown with high-content immunofluorescence microscopy (cilia number, length, cargo transport assays)","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean siRNA knockdown with defined phenotypic readout across three cell lines, two orthogonal cargo transport assays, but single lab","pmids":["21289087"],"is_preprint":false},{"year":2018,"finding":"IQUB overexpression promotes breast cancer cell proliferation and migration by activating Akt, which phosphorylates GSK3β, in turn activating the Wnt/β-catenin signaling pathway; knockdown of IQUB inhibits these effects and causes G1 cell cycle arrest.","method":"IQUB overexpression and knockdown in MCF-7 and MDA-MB-231 cells combined with LiCl (GSK3β inhibitor) and MG-132 (proteasome inhibitor) treatment, proliferation/migration assays, cell cycle analysis","journal":"Cancer medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function and gain-of-function with pharmacological pathway interrogation, single lab, multiple orthogonal readouts","pmids":["29968965"],"is_preprint":false},{"year":2022,"finding":"IQUB is required for assembly of radial spoke 1 (RS1) specifically in sperm flagella but not in tracheal cilia of mice; Iqub knockout abolishes the entire RS1 in sperm flagella, causing male infertility due to sperm motility defects, while triple radial spokes remain intact in tracheal cilia.","method":"Iqub knockout mouse model, transmission electron microscopy of sperm flagella and tracheal cilia ultrastructure, fertility assays","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout mouse model with ultrastructural TEM confirmation and defined cellular phenotype (RS1 loss, male infertility), replicated in subsequent independent studies","pmids":["36417862"],"is_preprint":false},{"year":2023,"finding":"IQUB interacts with radial spoke head protein RSPH3, CEP295NL (DDC8), GSTM1, and ODF1 in yeast two-hybrid assays. Functionally, IQUB recruits calmodulin in low-Ca²⁺ environments to facilitate radial spoke assembly by inhibiting the activity of an RSPH3/p-ERK1/2 non-typical AKAP complex; loss of IQUB causes radial spoke defects and asthenospermia in humans and mice.","method":"Yeast two-hybrid protein interaction screen, Iqub knockout and knockin mouse models, co-immunoprecipitation, western blot, scanning and transmission electron microscopy, whole-exome sequencing of human patients","journal":"Human reproduction (Oxford, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus KO/KI mouse models with ultrastructural phenotype, single lab, functional mechanism partly inferred from inhibitor studies","pmids":["36355624"],"is_preprint":false},{"year":2023,"finding":"IQUB protein is localized to the acrosome and flagellum of mature spermatozoa, and is expressed in spermatogenic cells at different developmental stages in mouse testis.","method":"Western blot and immunofluorescence with newly generated rabbit polyclonal antibody against mouse IQUB in wild-type mouse testis","journal":"Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — direct subcellular localization by immunofluorescence with validated antibody, single lab, no functional consequence directly tested in this paper","pmids":["37732581"],"is_preprint":false},{"year":2024,"finding":"IQUB is specifically downregulated in ARL3T31A/C118F mutant fibroblasts; re-expression of IQUB rescues the elongated cilia phenotype caused by these ARL3 mutations, placing IQUB downstream of ARL3 in a pathway controlling cilia length.","method":"Patient-derived transformed fibroblast cell lines, RNA-sequencing, proteomics, IQUB rescue overexpression with cilia morphology measurement","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis established by rescue experiment in patient-derived cells, two orthogonal omics methods plus functional validation, single lab","pmids":["38457249"],"is_preprint":false},{"year":2025,"finding":"IQUB acts as an adapter/scaffold for RS1 assembly in both human and mouse sperm flagella; loss of IQUB causes selective RS1 deficiency (not RS2 or RS3), co-dependent loss of inner dynein arm components DNAH7 and DNAH12, and reduced sperm kinetic parameters. Twelve RS1 components were identified (RSPH3, RSPH6A, RSPH9, DYDC1, NME5, DNAJB13, PPIL6, AK8, ROPN1L, RSPH14, DYNLL1, IQUB), with IQUB localized to the RS1 stalk.","method":"Whole-exome sequencing of infertile males, Iqub-/- mouse model, computer-aided sperm analysis, electron microscopy, protein mass spectrometry, western blot, bioinformatic structural modeling, ICSI","journal":"Cell communication and signaling : CCS","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multi-method study (proteomics, KO mouse, electron microscopy, human genetic variant) with structural modeling and independent replication of core IQUB-RS1 finding across labs","pmids":["39849482"],"is_preprint":false}],"current_model":"IQUB is a ciliary/flagellar scaffold protein required for the assembly of radial spoke 1 (RS1) on the axonemal A-microtubule doublet in mammalian sperm flagella; it localizes to the RS1 stalk, recruits calmodulin under low-Ca²⁺ conditions to suppress aberrant RSPH3/p-ERK1/2 AKAP activity, interacts with RSPH3, CEP295NL, GSTM1, and ODF1, and its loss selectively abolishes RS1 and co-depletes inner dynein arm components DNAH7/DNAH12, causing asthenospermia and male infertility; in somatic cells IQUB also regulates cilia length downstream of ARL3, and in cancer cells it promotes proliferation and migration via the Akt/GSK3β/β-catenin pathway."},"narrative":{"mechanistic_narrative":"IQUB is a ciliary/flagellar scaffold protein whose principal characterized role is the assembly of radial spoke 1 (RS1) on the axoneme of mammalian sperm flagella [PMID:36417862, PMID:39849482]. Genetic ablation in mice and humans selectively abolishes RS1 — leaving RS2 and RS3 intact — and co-depletes the inner dynein arm components DNAH7 and DNAH12, reducing sperm motility and causing asthenospermia and male infertility [PMID:36417862, PMID:39849482]. IQUB localizes to the RS1 stalk and is one of twelve identified RS1 components, where it acts as an adapter that nucleates spoke assembly [PMID:39849482]. It interacts with the radial spoke head protein RSPH3 as well as CEP295NL, GSTM1, and ODF1, and recruits calmodulin under low-Ca²⁺ conditions to suppress the activity of an RSPH3/p-ERK1/2 non-typical AKAP complex during spoke assembly [PMID:36355624]. Within the male germline, IQUB protein localizes to the acrosome and flagellum of mature spermatozoa and is expressed across spermatogenic stages [PMID:37732581]. Beyond the flagellum, IQUB regulates primary cilium length in somatic cells, acting downstream of ARL3 — re-expression of IQUB rescues the elongated-cilia phenotype of ARL3 mutant fibroblasts [PMID:21289087, PMID:38457249]. IQUB also promotes breast cancer cell proliferation and migration by activating Akt-mediated GSK3β phosphorylation and downstream Wnt/β-catenin signaling, with its loss causing G1 cell cycle arrest [PMID:29968965].","teleology":[{"year":2011,"claim":"Established the first cellular function for IQUB by showing it constrains cilia length, identifying it as a ciliary regulator rather than an uncharacterized protein.","evidence":"siRNA knockdown with high-content immunofluorescence across three vertebrate cell lines and cargo transport assays","pmids":["21289087"],"confidence":"Medium","gaps":["Molecular mechanism of length control not defined","No interacting partners identified","Single-lab knockdown without genetic confirmation"]},{"year":2018,"claim":"Revealed a non-ciliary signaling role, linking IQUB to a proliferative cascade and showing it is not exclusively a structural ciliary protein.","evidence":"Overexpression and knockdown in MCF-7 and MDA-MB-231 cells with GSK3β and proteasome inhibitors, proliferation/migration and cell cycle assays","pmids":["29968965"],"confidence":"Medium","gaps":["Direct biochemical link between IQUB and Akt not established","Mechanism connecting ciliary scaffold function to oncogenic signaling unclear","Single cancer-type context"]},{"year":2022,"claim":"Defined IQUB's core structural function by showing it is selectively required for radial spoke 1 assembly in sperm flagella but dispensable for tracheal cilia spokes, explaining tissue-specific motility phenotypes.","evidence":"Iqub knockout mouse with TEM of sperm flagella and tracheal cilia and fertility assays","pmids":["36417862"],"confidence":"High","gaps":["Reason for tissue selectivity (sperm vs trachea) not explained","Molecular interactions within RS1 not yet mapped"]},{"year":2023,"claim":"Identified IQUB's direct binding partners and a calmodulin/Ca²⁺-dependent regulatory mechanism, providing the molecular basis for how it controls radial spoke assembly.","evidence":"Yeast two-hybrid screen, reciprocal Co-IP, KO/KI mouse models, EM, and whole-exome sequencing of patients","pmids":["36355624"],"confidence":"Medium","gaps":["AKAP-inhibition mechanism partly inferred from inhibitor studies","Calmodulin recruitment not structurally resolved","Stoichiometry of interactions undefined"]},{"year":2023,"claim":"Confirmed the subcellular distribution of IQUB protein in the male germline, localizing it to the acrosome and flagellum and across spermatogenic stages.","evidence":"Western blot and immunofluorescence with a newly generated antibody in wild-type mouse testis","pmids":["37732581"],"confidence":"Medium","gaps":["No functional consequence tested in this study","Acrosomal role not mechanistically characterized"]},{"year":2024,"claim":"Placed IQUB in an ARL3-dependent pathway controlling cilia length via epistasis, connecting its somatic ciliary function to an upstream regulator.","evidence":"Patient-derived ARL3 mutant fibroblasts, RNA-seq, proteomics, and IQUB rescue with cilia morphology measurement","pmids":["38457249"],"confidence":"Medium","gaps":["Mechanism by which ARL3 regulates IQUB expression unknown","Whether ARL3 acts on IQUB in flagella as in somatic cilia untested"]},{"year":2025,"claim":"Consolidated IQUB as an RS1 adapter/scaffold and defined RS1 composition, showing IQUB loss causes selective RS1 deficiency and co-dependent loss of inner dynein arm DNAH7/DNAH12 across human and mouse.","evidence":"Whole-exome sequencing of infertile males, Iqub-/- mouse, CASA, EM, mass spectrometry, structural modeling, and ICSI","pmids":["39849482"],"confidence":"High","gaps":["Mechanism linking RS1 loss to inner dynein arm depletion not resolved","Structural model not experimentally validated","Order of assembly within RS1 stalk undefined"]},{"year":null,"claim":"How IQUB's structural role in radial spoke assembly mechanistically connects to its signaling functions in somatic cilia length control and Akt/Wnt-driven proliferation remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying biochemical mechanism across flagellar, ciliary, and oncogenic contexts","Calmodulin/Ca²⁺ regulation not tested in somatic cilia","No structural data on full-length IQUB complexes"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[3,6]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[2,6]}],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[0,2,4,6]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[2,6]}],"pathway":[{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,5]}],"complexes":["radial spoke 1 (RS1)"],"partners":["RSPH3","CEP295NL","GSTM1","ODF1","CALMODULIN","ARL3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8NA54","full_name":"IQ motif and ubiquitin-like domain-containing protein","aliases":[],"length_aa":791,"mass_kda":92.6,"function":"Adapter protein that anchors the radial spoke 1 (RS1) complex to the A microtubule of outer doublet microtubules in axonemes (PubMed:36355624). The triple radial spokes (RS1, RS2 and RS3) are required to modulate beating of the sperm flagellum (PubMed:36355624). May play a role in inhibiting signaling via MAPK1/ERK2 and MAPK3/ERK1 (PubMed:36355624). Additionally, may play a role in the functioning of cilia (By similarity). Not required for the functioning of tracheal or ependymal cilia (By similarity)","subcellular_location":"Cytoplasm, cytoskeleton, flagellum axoneme; Cell projection, cilium","url":"https://www.uniprot.org/uniprotkb/Q8NA54/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/IQUB","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/IQUB","total_profiled":1310},"omim":[{"mim_id":"620557","title":"IQ MOTIF- AND UBIQUITIN DOMAIN-CONTAINING PROTEIN; IQUB","url":"https://www.omim.org/entry/620557"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nuclear speckles","reliability":"Approved"},{"location":"Mid piece","reliability":"Approved"},{"location":"Principal piece","reliability":"Approved"},{"location":"End piece","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"testis","ntpm":31.3}],"url":"https://www.proteinatlas.org/search/IQUB"},"hgnc":{"alias_symbol":["FLJ35834"],"prev_symbol":[]},"alphafold":{"accession":"Q8NA54","domains":[{"cath_id":"3.10.20.90","chopping":"128-203","consensus_level":"high","plddt":85.8339,"start":128,"end":203},{"cath_id":"-","chopping":"640-773","consensus_level":"high","plddt":82.6294,"start":640,"end":773},{"cath_id":"1.10.287","chopping":"399-469","consensus_level":"medium","plddt":91.9873,"start":399,"end":469},{"cath_id":"1.20.120","chopping":"483-585","consensus_level":"medium","plddt":90.4597,"start":483,"end":585}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NA54","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NA54-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NA54-F1-predicted_aligned_error_v6.png","plddt_mean":75.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=IQUB","jax_strain_url":"https://www.jax.org/strain/search?query=IQUB"},"sequence":{"accession":"Q8NA54","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NA54.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NA54/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NA54"}},"corpus_meta":[{"pmid":"26330360","id":"PMC_26330360","title":"Whole genome and transcriptome sequencing of matched primary and peritoneal metastatic gastric carcinoma.","date":"2015","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/26330360","citation_count":81,"is_preprint":false},{"pmid":"21289087","id":"PMC_21289087","title":"Functional characterization of putative cilia genes by high-content analysis.","date":"2011","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/21289087","citation_count":78,"is_preprint":false},{"pmid":"24348429","id":"PMC_24348429","title":"Rare Genomic Variants Link Bipolar Disorder with Anxiety Disorders to CREB-Regulated Intracellular Signaling Pathways.","date":"2013","source":"Frontiers in psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/24348429","citation_count":33,"is_preprint":false},{"pmid":"36417862","id":"PMC_36417862","title":"Differential requirements of IQUB for the assembly of radial spoke 1 and the motility of mouse cilia and flagella.","date":"2022","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/36417862","citation_count":26,"is_preprint":false},{"pmid":"29968965","id":"PMC_29968965","title":"Upregulated IQUB promotes cell proliferation and migration via activating Akt/GSK3β/β-catenin signaling pathway in breast cancer.","date":"2018","source":"Cancer medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29968965","citation_count":20,"is_preprint":false},{"pmid":"36339449","id":"PMC_36339449","title":"Combining bioinformatics, network pharmacology and artificial intelligence to predict the mechanism of celastrol in the treatment of type 2 diabetes.","date":"2022","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/36339449","citation_count":20,"is_preprint":false},{"pmid":"36355624","id":"PMC_36355624","title":"IQUB deficiency causes male infertility by affecting the activity of p-ERK1/2/RSPH3.","date":"2023","source":"Human reproduction (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36355624","citation_count":8,"is_preprint":false},{"pmid":"39849482","id":"PMC_39849482","title":"IQUB mutation induces radial spoke 1 deficiency causing asthenozoospermia with normal sperm morphology in humans and mice.","date":"2025","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/39849482","citation_count":6,"is_preprint":false},{"pmid":"38457249","id":"PMC_38457249","title":"Mechanisms underlying morphological and functional changes of cilia in fibroblasts derived from patients bearing ARL3T31A and ARL3T31A/C118F mutations.","date":"2024","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/38457249","citation_count":6,"is_preprint":false},{"pmid":"37277920","id":"PMC_37277920","title":"Transcriptome-wide profile of 1α,25 dihydroxyvitamin D3 in HTR-8/SVneo cells.","date":"2023","source":"The journal of obstetrics and gynaecology research","url":"https://pubmed.ncbi.nlm.nih.gov/37277920","citation_count":1,"is_preprint":false},{"pmid":"37732581","id":"PMC_37732581","title":"[Preparation and application of rabbit polyclonal antibody against mouse IQ and ubiquitin-like domain-containing protein (IQUB)].","date":"2023","source":"Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/37732581","citation_count":0,"is_preprint":false},{"pmid":"41602861","id":"PMC_41602861","title":"IQ motif family genes in male infertility: pathogenesis, mechanisms, and clinical perspectives.","date":"2026","source":"Frontiers in reproductive health","url":"https://pubmed.ncbi.nlm.nih.gov/41602861","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9207,"output_tokens":1968,"usd":0.02857,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8912,"output_tokens":2827,"usd":0.057618,"stage2_stop_reason":"end_turn"},"total_usd":0.086188,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"siRNA knockdown of Iqub in vertebrate cell lines results in elongated cilia, establishing a role for IQUB in regulating cilia length.\",\n      \"method\": \"siRNA knockdown with high-content immunofluorescence microscopy (cilia number, length, cargo transport assays)\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean siRNA knockdown with defined phenotypic readout across three cell lines, two orthogonal cargo transport assays, but single lab\",\n      \"pmids\": [\"21289087\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"IQUB overexpression promotes breast cancer cell proliferation and migration by activating Akt, which phosphorylates GSK3β, in turn activating the Wnt/β-catenin signaling pathway; knockdown of IQUB inhibits these effects and causes G1 cell cycle arrest.\",\n      \"method\": \"IQUB overexpression and knockdown in MCF-7 and MDA-MB-231 cells combined with LiCl (GSK3β inhibitor) and MG-132 (proteasome inhibitor) treatment, proliferation/migration assays, cell cycle analysis\",\n      \"journal\": \"Cancer medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function and gain-of-function with pharmacological pathway interrogation, single lab, multiple orthogonal readouts\",\n      \"pmids\": [\"29968965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"IQUB is required for assembly of radial spoke 1 (RS1) specifically in sperm flagella but not in tracheal cilia of mice; Iqub knockout abolishes the entire RS1 in sperm flagella, causing male infertility due to sperm motility defects, while triple radial spokes remain intact in tracheal cilia.\",\n      \"method\": \"Iqub knockout mouse model, transmission electron microscopy of sperm flagella and tracheal cilia ultrastructure, fertility assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout mouse model with ultrastructural TEM confirmation and defined cellular phenotype (RS1 loss, male infertility), replicated in subsequent independent studies\",\n      \"pmids\": [\"36417862\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"IQUB interacts with radial spoke head protein RSPH3, CEP295NL (DDC8), GSTM1, and ODF1 in yeast two-hybrid assays. Functionally, IQUB recruits calmodulin in low-Ca²⁺ environments to facilitate radial spoke assembly by inhibiting the activity of an RSPH3/p-ERK1/2 non-typical AKAP complex; loss of IQUB causes radial spoke defects and asthenospermia in humans and mice.\",\n      \"method\": \"Yeast two-hybrid protein interaction screen, Iqub knockout and knockin mouse models, co-immunoprecipitation, western blot, scanning and transmission electron microscopy, whole-exome sequencing of human patients\",\n      \"journal\": \"Human reproduction (Oxford, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus KO/KI mouse models with ultrastructural phenotype, single lab, functional mechanism partly inferred from inhibitor studies\",\n      \"pmids\": [\"36355624\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"IQUB protein is localized to the acrosome and flagellum of mature spermatozoa, and is expressed in spermatogenic cells at different developmental stages in mouse testis.\",\n      \"method\": \"Western blot and immunofluorescence with newly generated rabbit polyclonal antibody against mouse IQUB in wild-type mouse testis\",\n      \"journal\": \"Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — direct subcellular localization by immunofluorescence with validated antibody, single lab, no functional consequence directly tested in this paper\",\n      \"pmids\": [\"37732581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"IQUB is specifically downregulated in ARL3T31A/C118F mutant fibroblasts; re-expression of IQUB rescues the elongated cilia phenotype caused by these ARL3 mutations, placing IQUB downstream of ARL3 in a pathway controlling cilia length.\",\n      \"method\": \"Patient-derived transformed fibroblast cell lines, RNA-sequencing, proteomics, IQUB rescue overexpression with cilia morphology measurement\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis established by rescue experiment in patient-derived cells, two orthogonal omics methods plus functional validation, single lab\",\n      \"pmids\": [\"38457249\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"IQUB acts as an adapter/scaffold for RS1 assembly in both human and mouse sperm flagella; loss of IQUB causes selective RS1 deficiency (not RS2 or RS3), co-dependent loss of inner dynein arm components DNAH7 and DNAH12, and reduced sperm kinetic parameters. Twelve RS1 components were identified (RSPH3, RSPH6A, RSPH9, DYDC1, NME5, DNAJB13, PPIL6, AK8, ROPN1L, RSPH14, DYNLL1, IQUB), with IQUB localized to the RS1 stalk.\",\n      \"method\": \"Whole-exome sequencing of infertile males, Iqub-/- mouse model, computer-aided sperm analysis, electron microscopy, protein mass spectrometry, western blot, bioinformatic structural modeling, ICSI\",\n      \"journal\": \"Cell communication and signaling : CCS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multi-method study (proteomics, KO mouse, electron microscopy, human genetic variant) with structural modeling and independent replication of core IQUB-RS1 finding across labs\",\n      \"pmids\": [\"39849482\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"IQUB is a ciliary/flagellar scaffold protein required for the assembly of radial spoke 1 (RS1) on the axonemal A-microtubule doublet in mammalian sperm flagella; it localizes to the RS1 stalk, recruits calmodulin under low-Ca²⁺ conditions to suppress aberrant RSPH3/p-ERK1/2 AKAP activity, interacts with RSPH3, CEP295NL, GSTM1, and ODF1, and its loss selectively abolishes RS1 and co-depletes inner dynein arm components DNAH7/DNAH12, causing asthenospermia and male infertility; in somatic cells IQUB also regulates cilia length downstream of ARL3, and in cancer cells it promotes proliferation and migration via the Akt/GSK3β/β-catenin pathway.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"IQUB is a ciliary/flagellar scaffold protein whose principal characterized role is the assembly of radial spoke 1 (RS1) on the axoneme of mammalian sperm flagella [#2, #6]. Genetic ablation in mice and humans selectively abolishes RS1 — leaving RS2 and RS3 intact — and co-depletes the inner dynein arm components DNAH7 and DNAH12, reducing sperm motility and causing asthenospermia and male infertility [#2, #6]. IQUB localizes to the RS1 stalk and is one of twelve identified RS1 components, where it acts as an adapter that nucleates spoke assembly [#6]. It interacts with the radial spoke head protein RSPH3 as well as CEP295NL, GSTM1, and ODF1, and recruits calmodulin under low-Ca\\u00b2\\u207a conditions to suppress the activity of an RSPH3/p-ERK1/2 non-typical AKAP complex during spoke assembly [#3]. Within the male germline, IQUB protein localizes to the acrosome and flagellum of mature spermatozoa and is expressed across spermatogenic stages [#4]. Beyond the flagellum, IQUB regulates primary cilium length in somatic cells, acting downstream of ARL3 — re-expression of IQUB rescues the elongated-cilia phenotype of ARL3 mutant fibroblasts [#0, #5]. IQUB also promotes breast cancer cell proliferation and migration by activating Akt-mediated GSK3\\u03b2 phosphorylation and downstream Wnt/\\u03b2-catenin signaling, with its loss causing G1 cell cycle arrest [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Established the first cellular function for IQUB by showing it constrains cilia length, identifying it as a ciliary regulator rather than an uncharacterized protein.\",\n      \"evidence\": \"siRNA knockdown with high-content immunofluorescence across three vertebrate cell lines and cargo transport assays\",\n      \"pmids\": [\"21289087\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of length control not defined\", \"No interacting partners identified\", \"Single-lab knockdown without genetic confirmation\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Revealed a non-ciliary signaling role, linking IQUB to a proliferative cascade and showing it is not exclusively a structural ciliary protein.\",\n      \"evidence\": \"Overexpression and knockdown in MCF-7 and MDA-MB-231 cells with GSK3\\u03b2 and proteasome inhibitors, proliferation/migration and cell cycle assays\",\n      \"pmids\": [\"29968965\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical link between IQUB and Akt not established\", \"Mechanism connecting ciliary scaffold function to oncogenic signaling unclear\", \"Single cancer-type context\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined IQUB's core structural function by showing it is selectively required for radial spoke 1 assembly in sperm flagella but dispensable for tracheal cilia spokes, explaining tissue-specific motility phenotypes.\",\n      \"evidence\": \"Iqub knockout mouse with TEM of sperm flagella and tracheal cilia and fertility assays\",\n      \"pmids\": [\"36417862\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Reason for tissue selectivity (sperm vs trachea) not explained\", \"Molecular interactions within RS1 not yet mapped\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified IQUB's direct binding partners and a calmodulin/Ca\\u00b2\\u207a-dependent regulatory mechanism, providing the molecular basis for how it controls radial spoke assembly.\",\n      \"evidence\": \"Yeast two-hybrid screen, reciprocal Co-IP, KO/KI mouse models, EM, and whole-exome sequencing of patients\",\n      \"pmids\": [\"36355624\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"AKAP-inhibition mechanism partly inferred from inhibitor studies\", \"Calmodulin recruitment not structurally resolved\", \"Stoichiometry of interactions undefined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Confirmed the subcellular distribution of IQUB protein in the male germline, localizing it to the acrosome and flagellum and across spermatogenic stages.\",\n      \"evidence\": \"Western blot and immunofluorescence with a newly generated antibody in wild-type mouse testis\",\n      \"pmids\": [\"37732581\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional consequence tested in this study\", \"Acrosomal role not mechanistically characterized\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed IQUB in an ARL3-dependent pathway controlling cilia length via epistasis, connecting its somatic ciliary function to an upstream regulator.\",\n      \"evidence\": \"Patient-derived ARL3 mutant fibroblasts, RNA-seq, proteomics, and IQUB rescue with cilia morphology measurement\",\n      \"pmids\": [\"38457249\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which ARL3 regulates IQUB expression unknown\", \"Whether ARL3 acts on IQUB in flagella as in somatic cilia untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Consolidated IQUB as an RS1 adapter/scaffold and defined RS1 composition, showing IQUB loss causes selective RS1 deficiency and co-dependent loss of inner dynein arm DNAH7/DNAH12 across human and mouse.\",\n      \"evidence\": \"Whole-exome sequencing of infertile males, Iqub-/- mouse, CASA, EM, mass spectrometry, structural modeling, and ICSI\",\n      \"pmids\": [\"39849482\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking RS1 loss to inner dynein arm depletion not resolved\", \"Structural model not experimentally validated\", \"Order of assembly within RS1 stalk undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How IQUB's structural role in radial spoke assembly mechanistically connects to its signaling functions in somatic cilia length control and Akt/Wnt-driven proliferation remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying biochemical mechanism across flagellar, ciliary, and oncogenic contexts\", \"Calmodulin/Ca\\u00b2\\u207a regulation not tested in somatic cilia\", \"No structural data on full-length IQUB complexes\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [3, 6]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [2, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [0, 2, 4, 6]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [2, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"complexes\": [\n      \"radial spoke 1 (RS1)\"\n    ],\n    \"partners\": [\n      \"RSPH3\",\n      \"CEP295NL\",\n      \"GSTM1\",\n      \"ODF1\",\n      \"calmodulin\",\n      \"ARL3\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":7,"faith_pct":85.71428571428571}}