{"gene":"TBC1D32","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2018,"finding":"Dzip1l has overlapping functions with Bromi (Tbc1d32) in ciliogenesis, cilia morphogenesis, and neural tube patterning, as shown by genetic redundancy experiments in mouse; loss of both factors produces additive ciliopathy phenotypes.","method":"Genetic epistasis / double-mutant mouse analysis with ciliary morphology readouts","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo genetic redundancy established by double-mutant mouse phenotype with specific cellular readouts, single study","pmids":["29487109"],"is_preprint":false},{"year":2021,"finding":"CCRK/CDK20 regulates retrograde ciliary protein trafficking and IFT turnaround at ciliary tips in concert with BROMI/TBC1D32; a CCRK mutant defective in BROMI binding failed to rescue CCRK-KO phenotypes (overaccumulation of IFT proteins at bulged ciliary tips, enrichment of GPR161 and Smoothened on ciliary membrane), indicating that the CCRK–BROMI interaction is required for this function.","method":"CCRK-knockout cell lines, rescue experiments with wild-type CCRK vs. kinase-dead mutant vs. BROMI-binding-defective mutant, immunofluorescence of IFT proteins and ciliary membrane receptors","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 / Moderate — KO cells with specific phenotypic readouts, multiple mutant rescue experiments in a single study establishing both the interaction and its functional requirement","pmids":["34624068"],"is_preprint":false},{"year":2022,"finding":"BROMI/TBC1D32 interacts with CCRK/CDK20, CFAP20 (an evolutionarily conserved ciliary protein), and FAM149B1/JBTS36; BROMI mutants defective in binding to either CCRK or CFAP20 fail to rescue ciliary defects (abnormally long cilia, IFT machinery accumulation at ciliary tip) in BROMI-KO cells, placing BROMI in a complex with CCRK, FAM149B1, and CFAP20 that regulates IFT turnaround under control of ICK/CILK1.","method":"Co-immunoprecipitation, BROMI-knockout cell rescue with binding-defective mutants, immunofluorescence of IFT proteins and cilia length measurements","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal interactions established by Co-IP, functional requirement validated by domain-specific rescue failure in KO cells, multiple orthogonal methods in single study","pmids":["35609210"],"is_preprint":false},{"year":2020,"finding":"TBC1D32 interacts with proteins implicated in cilium assembly, Sonic Hedgehog (Shh) signaling, and brain development, as identified by stable and dynamic protein–protein interaction pulldowns from HEK cells followed by mass spectrometry; TBC1D32 is expressed in developing hypothalamus, Rathke's pouch, and hindbrain.","method":"Affinity pulldown from HEK cells followed by mass spectrometry; in situ hybridization for expression profiling","journal":"The Journal of clinical endocrinology and metabolism","confidence":"Medium","confidence_rationale":"Tier 3 / Weak — single pulldown-MS experiment identifying interaction partners, limited functional follow-up in this paper","pmids":["32060556"],"is_preprint":false},{"year":2023,"finding":"TBC1D32 plays a role in ciliogenesis of the retinal pigment epithelium (RPE); loss of TBC1D32 in iPSC-derived RPE and Xenopus in vivo models causes elongated ciliary defects, disrupted apical tight junctions, loss of retinoid cycling functionality, altered secretion balance, onset of epithelial-mesenchymal transition-like phenotype, and photoreceptor connecting cilium anomalies with impaired trafficking to the outer segment.","method":"Xenopus in vivo knockdown/knockout, human iPSC-derived retinal organoids and RPE models, immunofluorescence of ciliary markers, functional assays (retinoid cycling, secretion balance)","journal":"JCI insight","confidence":"High","confidence_rationale":"Tier 2 / Moderate — loss-of-function in two independent model systems (Xenopus in vivo and iPSC-derived retinal models) with multiple orthogonal functional readouts","pmids":["37768732"],"is_preprint":false}],"current_model":"TBC1D32/BROMI is a ciliary protein that forms a complex with CCRK/CDK20, FAM149B1/JBTS36, and CFAP20 to regulate intraflagellar transport (IFT) turnaround at the ciliary tip downstream of ICK/CILK1 kinase activation; it is also required for ciliary bud formation (acting redundantly with Dzip1l), RPE ciliogenesis, and photoreceptor connecting cilium integrity, positioning it as a central regulator of ciliogenesis and Hedgehog/Smoothened signaling in multiple tissues."},"narrative":{"mechanistic_narrative":"TBC1D32 (BROMI) is a ciliary protein that regulates intraflagellar transport (IFT) turnaround at the ciliary tip and is required for proper ciliogenesis and Hedgehog signaling across multiple tissues [PMID:35609210, PMID:34624068]. It functions within a complex containing the kinase CCRK/CDK20, FAM149B1/JBTS36, and the conserved ciliary protein CFAP20, where BROMI mutants defective in binding either CCRK or CFAP20 fail to rescue the abnormally long cilia and tip accumulation of IFT machinery seen in BROMI-knockout cells, placing the complex under the control of ICK/CILK1 [PMID:35609210]. The CCRK–BROMI interaction is specifically required for retrograde ciliary trafficking and IFT turnaround, since a CCRK mutant unable to bind BROMI cannot reverse the overaccumulation of IFT proteins at bulged ciliary tips or the abnormal enrichment of GPR161 and Smoothened on the ciliary membrane [PMID:34624068]. In vivo, TBC1D32 acts redundantly with Dzip1l in ciliogenesis, cilia morphogenesis, and neural tube patterning [PMID:29487109], and is required for retinal pigment epithelium ciliogenesis, epithelial integrity, retinoid cycling, and photoreceptor connecting cilium function [PMID:37768732]. Beyond these roles, the biochemical activity of the TBC domain itself has not been characterized in the available corpus.","teleology":[{"year":2018,"claim":"Established that Bromi/Tbc1d32 operates in the same biological program as Dzip1l, resolving whether it acts alone or shares function in cilium formation and patterning.","evidence":"Double-mutant mouse genetic epistasis with ciliary morphology and neural tube readouts","pmids":["29487109"],"confidence":"Medium","gaps":["Molecular basis of the redundancy not defined","No direct physical interaction with Dzip1l shown","Does not identify the biochemical activity of Tbc1d32"]},{"year":2020,"claim":"Defined the interaction landscape of TBC1D32 and its expression domains, linking it to cilium assembly, Shh signaling, and brain development.","evidence":"Affinity pulldown-mass spectrometry from HEK cells plus in situ hybridization expression profiling","pmids":["32060556"],"confidence":"Medium","gaps":["Interactions identified by single pulldown-MS without reciprocal validation","Limited functional follow-up","Functional consequences of individual interactions not tested"]},{"year":2021,"claim":"Showed that the CCRK–BROMI interaction is functionally required for retrograde ciliary trafficking and IFT turnaround, distinguishing the interaction from CCRK kinase activity per se.","evidence":"CCRK-knockout cell lines rescued with wild-type, kinase-dead, and BROMI-binding-defective CCRK mutants; immunofluorescence of IFT proteins, GPR161, and Smoothened","pmids":["34624068"],"confidence":"High","gaps":["Does not resolve how BROMI mechanistically promotes IFT turnaround","TBC domain catalytic role unaddressed","Direct vs. indirect effect on receptor enrichment not separated"]},{"year":2022,"claim":"Placed BROMI in a defined multiprotein complex with CCRK, FAM149B1/JBTS36, and CFAP20, and showed both CCRK- and CFAP20-binding are required for ciliary length control and IFT turnaround under ICK/CILK1 control.","evidence":"Co-immunoprecipitation and BROMI-knockout cell rescue with binding-defective mutants, with IFT immunofluorescence and cilia length measurements","pmids":["35609210"],"confidence":"High","gaps":["Stoichiometry and architecture of the complex unknown","No structural model of the assembly","How ICK/CILK1 signaling is transmitted to the complex not defined"]},{"year":2023,"claim":"Extended TBC1D32 function to retinal tissue, establishing its requirement for RPE ciliogenesis, epithelial integrity, retinoid cycling, and photoreceptor connecting cilium integrity.","evidence":"Xenopus in vivo loss-of-function and human iPSC-derived RPE/retinal organoid models with ciliary markers and functional assays","pmids":["37768732"],"confidence":"High","gaps":["Whether retinal phenotypes depend on the CCRK/CFAP20 complex not tested","Mechanism linking ciliary defect to EMT-like phenotype unclear","No causative human disease mutation established in this study"]},{"year":null,"claim":"The intrinsic biochemical activity of the TBC1D32 TBC domain and how the BROMI complex molecularly executes IFT turnaround remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No demonstrated GAP or catalytic activity for the TBC domain","No structure of the BROMI-containing complex","Mechanistic coupling between ICK/CILK1 phosphorylation and IFT turnaround undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,2]}],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[1,2,4]}],"pathway":[{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[0,2,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,3]}],"complexes":["BROMI–CCRK–FAM149B1–CFAP20 complex"],"partners":["CCRK","CFAP20","FAM149B1","DZIP1L"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96NH3","full_name":"Protein broad-minded","aliases":["TBC1 domain family member 32"],"length_aa":1257,"mass_kda":144.8,"function":"Required for high-level Shh responses in the developing neural tube. Together with CDK20, controls the structure of the primary cilium by coordinating assembly of the ciliary membrane and axoneme, allowing GLI2 to be properly activated in response to Shh signaling (By similarity)","subcellular_location":"Cytoplasm; Cell projection, cilium","url":"https://www.uniprot.org/uniprotkb/Q96NH3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TBC1D32","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/TBC1D32","total_profiled":1310},"omim":[{"mim_id":"621307","title":"ALSAHAN-HARRIS SYNDROME; ALHAS","url":"https://www.omim.org/entry/621307"},{"mim_id":"621280","title":"RETINITIS PIGMENTOSA 100; RP100","url":"https://www.omim.org/entry/621280"},{"mim_id":"618763","title":"JOUBERT SYNDROME 36; JBTS36","url":"https://www.omim.org/entry/618763"},{"mim_id":"618413","title":"FAMILY WITH SEQUENCE SIMILARITY 149, MEMBER B1; FAM149B1","url":"https://www.omim.org/entry/618413"},{"mim_id":"615867","title":"TBC1 DOMAIN FAMILY, MEMBER 32; TBC1D32","url":"https://www.omim.org/entry/615867"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Mitochondria","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"retina","ntpm":6.9}],"url":"https://www.proteinatlas.org/search/TBC1D32"},"hgnc":{"alias_symbol":["FLJ30899","dJ310J6.1","FLJ34235","bA57L9.1","BROMI"],"prev_symbol":["C6orf171","C6orf170"]},"alphafold":{"accession":"Q96NH3","domains":[{"cath_id":"-","chopping":"7-80_96-132","consensus_level":"high","plddt":81.358,"start":7,"end":132},{"cath_id":"-","chopping":"752-856","consensus_level":"medium","plddt":75.9943,"start":752,"end":856},{"cath_id":"-","chopping":"858-915","consensus_level":"medium","plddt":84.7441,"start":858,"end":915},{"cath_id":"-","chopping":"998-1119","consensus_level":"medium","plddt":91.4892,"start":998,"end":1119},{"cath_id":"-","chopping":"1123-1168_1187-1251","consensus_level":"high","plddt":94.4012,"start":1123,"end":1251},{"cath_id":"1.10.220","chopping":"172-245","consensus_level":"high","plddt":74.7374,"start":172,"end":245},{"cath_id":"1.20.1050","chopping":"273-330_338-401_417-450","consensus_level":"medium","plddt":87.4493,"start":273,"end":450}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96NH3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96NH3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96NH3-F1-predicted_aligned_error_v6.png","plddt_mean":80.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TBC1D32","jax_strain_url":"https://www.jax.org/strain/search?query=TBC1D32"},"sequence":{"accession":"Q96NH3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96NH3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96NH3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96NH3"}},"corpus_meta":[{"pmid":"18226934","id":"PMC_18226934","title":"Homologs of ToxB, a host-selective toxin gene from Pyrenophora tritici-repentis, are present in the genome of sister-species Pyrenophora bromi and other members of the Ascomycota.","date":"2007","source":"Fungal genetics and biology : FG & B","url":"https://pubmed.ncbi.nlm.nih.gov/18226934","citation_count":38,"is_preprint":false},{"pmid":"29487109","id":"PMC_29487109","title":"Centrosomal protein Dzip1l binds Cby, promotes ciliary bud formation, and acts redundantly with Bromi to regulate ciliogenesis in the mouse.","date":"2018","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/29487109","citation_count":22,"is_preprint":false},{"pmid":"32060556","id":"PMC_32060556","title":"Loss-of-Function Variants in TBC1D32 Underlie Syndromic Hypopituitarism.","date":"2020","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/32060556","citation_count":21,"is_preprint":false},{"pmid":"37768732","id":"PMC_37768732","title":"TBC1D32 variants disrupt retinal ciliogenesis and cause retinitis pigmentosa.","date":"2023","source":"JCI insight","url":"https://pubmed.ncbi.nlm.nih.gov/37768732","citation_count":17,"is_preprint":false},{"pmid":"18944587","id":"PMC_18944587","title":"Genetic Variation Among Natural Populations of Tilletia controversa and T. bromi.","date":"2000","source":"Phytopathology","url":"https://pubmed.ncbi.nlm.nih.gov/18944587","citation_count":16,"is_preprint":false},{"pmid":"35609210","id":"PMC_35609210","title":"BROMI/TBC1D32 together with CCRK/CDK20 and FAM149B1/JBTS36 contributes to intraflagellar transport turnaround involving ICK/CILK1.","date":"2022","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/35609210","citation_count":12,"is_preprint":false},{"pmid":"34624068","id":"PMC_34624068","title":"CCRK/CDK20 regulates ciliary retrograde protein trafficking via interacting with BROMI/TBC1D32.","date":"2021","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/34624068","citation_count":10,"is_preprint":false},{"pmid":"21091157","id":"PMC_21091157","title":"Pyrenophora bromi, causal agent of brownspot of bromegrass, expresses a gene encoding a protein with homology and similar activity to Ptr ToxB, a host-selective toxin of wheat.","date":"2011","source":"Molecular plant-microbe interactions : MPMI","url":"https://pubmed.ncbi.nlm.nih.gov/21091157","citation_count":9,"is_preprint":false},{"pmid":"36826837","id":"PMC_36826837","title":"Diagnosis of TBC1D32-associated conditions: Expanding the phenotypic spectrum of a complex ciliopathy.","date":"2023","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/36826837","citation_count":3,"is_preprint":false},{"pmid":"39930170","id":"PMC_39930170","title":"Novel Potentially Pathogenic Variants in TBC1D32 Cause Non-syndromic Rod-Cone Degeneration.","date":"2025","source":"Advances in experimental medicine and biology","url":"https://pubmed.ncbi.nlm.nih.gov/39930170","citation_count":2,"is_preprint":false},{"pmid":"40702307","id":"PMC_40702307","title":"Expanding the clinical and molecular spectrum of TBC1D32-related ciliopathy: case reports and literature Review.","date":"2025","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40702307","citation_count":0,"is_preprint":false},{"pmid":"40319332","id":"PMC_40319332","title":"Two novel mutations in TBC1D32 add complexity to the oro-facial-digital syndrome.","date":"2025","source":"Human genomics","url":"https://pubmed.ncbi.nlm.nih.gov/40319332","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.10.08.617295","title":"Dissecting Regulatory Non-Coding Heart Disease GWAS Loci with High-Resolution 3D Chromatin Interactions Reveals Causal Genes with Pathophysiological Relevance to Heart Failure","date":"2024-10-13","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.08.617295","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7927,"output_tokens":1473,"usd":0.022938,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8205,"output_tokens":2252,"usd":0.048662,"stage2_stop_reason":"end_turn"},"total_usd":0.0716,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2018,\n      \"finding\": \"Dzip1l has overlapping functions with Bromi (Tbc1d32) in ciliogenesis, cilia morphogenesis, and neural tube patterning, as shown by genetic redundancy experiments in mouse; loss of both factors produces additive ciliopathy phenotypes.\",\n      \"method\": \"Genetic epistasis / double-mutant mouse analysis with ciliary morphology readouts\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo genetic redundancy established by double-mutant mouse phenotype with specific cellular readouts, single study\",\n      \"pmids\": [\"29487109\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"CCRK/CDK20 regulates retrograde ciliary protein trafficking and IFT turnaround at ciliary tips in concert with BROMI/TBC1D32; a CCRK mutant defective in BROMI binding failed to rescue CCRK-KO phenotypes (overaccumulation of IFT proteins at bulged ciliary tips, enrichment of GPR161 and Smoothened on ciliary membrane), indicating that the CCRK–BROMI interaction is required for this function.\",\n      \"method\": \"CCRK-knockout cell lines, rescue experiments with wild-type CCRK vs. kinase-dead mutant vs. BROMI-binding-defective mutant, immunofluorescence of IFT proteins and ciliary membrane receptors\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO cells with specific phenotypic readouts, multiple mutant rescue experiments in a single study establishing both the interaction and its functional requirement\",\n      \"pmids\": [\"34624068\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"BROMI/TBC1D32 interacts with CCRK/CDK20, CFAP20 (an evolutionarily conserved ciliary protein), and FAM149B1/JBTS36; BROMI mutants defective in binding to either CCRK or CFAP20 fail to rescue ciliary defects (abnormally long cilia, IFT machinery accumulation at ciliary tip) in BROMI-KO cells, placing BROMI in a complex with CCRK, FAM149B1, and CFAP20 that regulates IFT turnaround under control of ICK/CILK1.\",\n      \"method\": \"Co-immunoprecipitation, BROMI-knockout cell rescue with binding-defective mutants, immunofluorescence of IFT proteins and cilia length measurements\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interactions established by Co-IP, functional requirement validated by domain-specific rescue failure in KO cells, multiple orthogonal methods in single study\",\n      \"pmids\": [\"35609210\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"TBC1D32 interacts with proteins implicated in cilium assembly, Sonic Hedgehog (Shh) signaling, and brain development, as identified by stable and dynamic protein–protein interaction pulldowns from HEK cells followed by mass spectrometry; TBC1D32 is expressed in developing hypothalamus, Rathke's pouch, and hindbrain.\",\n      \"method\": \"Affinity pulldown from HEK cells followed by mass spectrometry; in situ hybridization for expression profiling\",\n      \"journal\": \"The Journal of clinical endocrinology and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single pulldown-MS experiment identifying interaction partners, limited functional follow-up in this paper\",\n      \"pmids\": [\"32060556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"TBC1D32 plays a role in ciliogenesis of the retinal pigment epithelium (RPE); loss of TBC1D32 in iPSC-derived RPE and Xenopus in vivo models causes elongated ciliary defects, disrupted apical tight junctions, loss of retinoid cycling functionality, altered secretion balance, onset of epithelial-mesenchymal transition-like phenotype, and photoreceptor connecting cilium anomalies with impaired trafficking to the outer segment.\",\n      \"method\": \"Xenopus in vivo knockdown/knockout, human iPSC-derived retinal organoids and RPE models, immunofluorescence of ciliary markers, functional assays (retinoid cycling, secretion balance)\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in two independent model systems (Xenopus in vivo and iPSC-derived retinal models) with multiple orthogonal functional readouts\",\n      \"pmids\": [\"37768732\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TBC1D32/BROMI is a ciliary protein that forms a complex with CCRK/CDK20, FAM149B1/JBTS36, and CFAP20 to regulate intraflagellar transport (IFT) turnaround at the ciliary tip downstream of ICK/CILK1 kinase activation; it is also required for ciliary bud formation (acting redundantly with Dzip1l), RPE ciliogenesis, and photoreceptor connecting cilium integrity, positioning it as a central regulator of ciliogenesis and Hedgehog/Smoothened signaling in multiple tissues.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TBC1D32 (BROMI) is a ciliary protein that regulates intraflagellar transport (IFT) turnaround at the ciliary tip and is required for proper ciliogenesis and Hedgehog signaling across multiple tissues [#2, #1]. It functions within a complex containing the kinase CCRK/CDK20, FAM149B1/JBTS36, and the conserved ciliary protein CFAP20, where BROMI mutants defective in binding either CCRK or CFAP20 fail to rescue the abnormally long cilia and tip accumulation of IFT machinery seen in BROMI-knockout cells, placing the complex under the control of ICK/CILK1 [#2]. The CCRK\\u2013BROMI interaction is specifically required for retrograde ciliary trafficking and IFT turnaround, since a CCRK mutant unable to bind BROMI cannot reverse the overaccumulation of IFT proteins at bulged ciliary tips or the abnormal enrichment of GPR161 and Smoothened on the ciliary membrane [#1]. In vivo, TBC1D32 acts redundantly with Dzip1l in ciliogenesis, cilia morphogenesis, and neural tube patterning [#0], and is required for retinal pigment epithelium ciliogenesis, epithelial integrity, retinoid cycling, and photoreceptor connecting cilium function [#4]. Beyond these roles, the biochemical activity of the TBC domain itself has not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2018,\n      \"claim\": \"Established that Bromi/Tbc1d32 operates in the same biological program as Dzip1l, resolving whether it acts alone or shares function in cilium formation and patterning.\",\n      \"evidence\": \"Double-mutant mouse genetic epistasis with ciliary morphology and neural tube readouts\",\n      \"pmids\": [\"29487109\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of the redundancy not defined\", \"No direct physical interaction with Dzip1l shown\", \"Does not identify the biochemical activity of Tbc1d32\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined the interaction landscape of TBC1D32 and its expression domains, linking it to cilium assembly, Shh signaling, and brain development.\",\n      \"evidence\": \"Affinity pulldown-mass spectrometry from HEK cells plus in situ hybridization expression profiling\",\n      \"pmids\": [\"32060556\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interactions identified by single pulldown-MS without reciprocal validation\", \"Limited functional follow-up\", \"Functional consequences of individual interactions not tested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showed that the CCRK\\u2013BROMI interaction is functionally required for retrograde ciliary trafficking and IFT turnaround, distinguishing the interaction from CCRK kinase activity per se.\",\n      \"evidence\": \"CCRK-knockout cell lines rescued with wild-type, kinase-dead, and BROMI-binding-defective CCRK mutants; immunofluorescence of IFT proteins, GPR161, and Smoothened\",\n      \"pmids\": [\"34624068\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not resolve how BROMI mechanistically promotes IFT turnaround\", \"TBC domain catalytic role unaddressed\", \"Direct vs. indirect effect on receptor enrichment not separated\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed BROMI in a defined multiprotein complex with CCRK, FAM149B1/JBTS36, and CFAP20, and showed both CCRK- and CFAP20-binding are required for ciliary length control and IFT turnaround under ICK/CILK1 control.\",\n      \"evidence\": \"Co-immunoprecipitation and BROMI-knockout cell rescue with binding-defective mutants, with IFT immunofluorescence and cilia length measurements\",\n      \"pmids\": [\"35609210\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and architecture of the complex unknown\", \"No structural model of the assembly\", \"How ICK/CILK1 signaling is transmitted to the complex not defined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended TBC1D32 function to retinal tissue, establishing its requirement for RPE ciliogenesis, epithelial integrity, retinoid cycling, and photoreceptor connecting cilium integrity.\",\n      \"evidence\": \"Xenopus in vivo loss-of-function and human iPSC-derived RPE/retinal organoid models with ciliary markers and functional assays\",\n      \"pmids\": [\"37768732\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether retinal phenotypes depend on the CCRK/CFAP20 complex not tested\", \"Mechanism linking ciliary defect to EMT-like phenotype unclear\", \"No causative human disease mutation established in this study\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The intrinsic biochemical activity of the TBC1D32 TBC domain and how the BROMI complex molecularly executes IFT turnaround remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No demonstrated GAP or catalytic activity for the TBC domain\", \"No structure of the BROMI-containing complex\", \"Mechanistic coupling between ICK/CILK1 phosphorylation and IFT turnaround undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [1, 2, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 3]}\n    ],\n    \"complexes\": [\"BROMI\\u2013CCRK\\u2013FAM149B1\\u2013CFAP20 complex\"],\n    \"partners\": [\"CCRK\", \"CFAP20\", \"FAM149B1\", \"DZIP1L\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":3,"faith_total":4,"faith_pct":75.0}}