{"gene":"BBS1","run_date":"2026-04-28T17:12:38","timeline":{"discoveries":[{"year":2002,"finding":"BBS1 was identified as the gene most commonly mutated in Bardet-Biedl syndrome, with a missense mutation (M390R) accounting for the majority of BBS1 cases; the gene product was shown to be highly conserved between mice and humans.","method":"Positional cloning, mutational analysis, sequence conservation analysis","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 — foundational positional cloning study with mutational validation, replicated across multiple subsequent studies","pmids":["12118255"],"is_preprint":false},{"year":2003,"finding":"BBS1 shares structural features (a conserved functional domain) with BBS2 and BBS7, suggesting these three proteins participate in a common functional pathway relevant to BBS pathogenesis.","method":"Phylogenetic and genomic comparative analysis, motif-based identification","journal":"American journal of human genetics","confidence":"Low","confidence_rationale":"Tier 4 — computational/sequence similarity analysis only, no direct biochemical validation","pmids":["12567324"],"is_preprint":false},{"year":2003,"finding":"Introduction of a BBS1 missense mutation into mammalian cells causes dramatic mislocalization of the BBS1 protein compared to wild-type, indicating the mutation disrupts normal subcellular targeting.","method":"Transfection of mutant BBS1 constructs into mammalian cells, fluorescence microscopy for localization","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 3 — single cell-based localization experiment with mutant vs. wild-type comparison, single lab","pmids":["12837689"],"is_preprint":false},{"year":2003,"finding":"BBS1 participates in oligogenic/non-Mendelian inheritance, genetically interacting with mutations at each of the other known BBS loci (BBS2, BBS4, BBS6, BBS7) to cause or modulate disease, demonstrating functional genetic interactions among BBS proteins.","method":"Genetic epistasis analysis, mutational screening of 259 BBS families, statistical modeling","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 2 — large-scale genetic epistasis study replicated across multiple families and labs","pmids":["12677556"],"is_preprint":false},{"year":2018,"finding":"BBS1 is required for retrograde trafficking of ciliary GPCRs (Smoothened and GPR161) out of cilia; BBS1 knockout cells show defects in ciliary entry of other BBSome subunits (BBS2, BBS7, BBS9) and ARL6, and the trafficking defect is rescued by wild-type BBS1 but not by a BBS9-binding-deficient BBS1 mutant. The ARL6/BBS3-BBS1 interaction is reinforced by BBS9, indicating BBS1 is central to BBSome assembly and ARL6-mediated membrane recruitment.","method":"BBS1 knockout cell lines, rescue with wild-type vs. mutant BBS1, immunofluorescence microscopy for ciliary GPCR localization, Co-IP for ARL6-BBS1-BBS9 interaction","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 — KO with defined phenotype, reciprocal interaction assays, structure-function mutagenesis rescue experiment","pmids":["29590217"],"is_preprint":false},{"year":2020,"finding":"BBSome assembly is a sequential process in which BBS4 nucleates a pre-BBSome at pericentriolar satellites, followed by BBS1-mediated translocation of the assembled BBSome to the ciliary base. BBS1 is required for the ciliary base localization step of BBSome biogenesis.","method":"Library of human cell lines deficient in individual BBSome subunits expressing fluorescently tagged subunits; biochemical fractionation, FRAP, fluorescence correlation spectroscopy, expansion microscopy","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal quantitative microscopy methods in defined KO cell lines, single lab","pmids":["32759308"],"is_preprint":false},{"year":2021,"finding":"BBS1 controls centrosome polarization toward the immune synapse in T cells by promoting clearance of centrosomal F-actin and its regulator WASH1 via proteasome-dependent degradation, coupling the 19S proteasome regulatory subunit to the microtubule motor dynein for transport to the centrosome.","method":"BBS1 knockdown/knockout in T cells, immunofluorescence for centrosome position and F-actin, Co-IP for BBS1-dynein-19S proteasome interactions, proteasome inhibitor experiments","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2-3 — defined cellular phenotype with mechanistic pathway placement, but single lab","pmids":["34423835"],"is_preprint":false},{"year":2022,"finding":"Bbs1 loss in zebrafish disrupts BBSome complex stability and leads to accumulation of membrane-associated proteins (particularly those involved in lipid homeostasis) in photoreceptor outer segments, resulting in elevated outer segment cholesterol content and early visual deficits preceding structural degeneration.","method":"bbs1 zebrafish mutant; quantitative proteomics and lipidomics on isolated outer segment-enriched samples; electroretinography for functional assessment","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1-2 — ortholog in zebrafish (consistent function), quantitative proteomics + lipidomics + functional ERG readout in the same study","pmids":["35277505"],"is_preprint":false},{"year":2021,"finding":"Ectopic expression of wild-type human BBS1 driven by the CAG promoter rescues male infertility (spermatozoa flagella assembly) but not retinal degeneration in Bbs1-M390R knock-in mice, indicating tissue-specific requirements for BBS1 expression levels.","method":"Transgenic mouse cross onto Bbs1M390R/M390R background; fertility testing; electroretinography; optical coherence tomography; immunohistochemistry; qRT-PCR for tissue expression","journal":"Gene therapy","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo rescue experiment with multiple functional readouts, single lab","pmids":["33664503"],"is_preprint":false},{"year":2022,"finding":"T cell-specific deletion of Bbs1 impairs CD4 T cell-mediated skin wound closure and alters splenic CD4/CD8 ratios upon Imiquimod stimulation, demonstrating a functional role for BBS1/BBSome in selective T cell immune responses.","method":"T cell-specific Bbs1 conditional knockout mice; flow cytometry; wound closure assay; Imiquimod treatment model","journal":"American journal of physiology. Regulatory, integrative and comparative physiology","confidence":"Medium","confidence_rationale":"Tier 2 — conditional KO with defined cellular phenotype, single lab","pmids":["36534590"],"is_preprint":false},{"year":2023,"finding":"BBS1 loss in renal collecting duct IMCD3 cells leads to failure to suppress mesenchymal cell identities (epithelial-to-mesenchymal transition) as cells differentiate, associated with loss of epithelial markers and tight junction formation; transcriptomic analysis of BBS mutant mouse hypothalamus and BBS patient fibroblasts confirms dysregulation of EMT genes as a general feature across tissues.","method":"CRISPR-edited clonal IMCD3 Bbs1 KO cell lines; phenotypic screen; multi-omics (transcriptomics); analysis of mouse hypothalamic preparations and patient fibroblasts","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2-3 — CRISPR KO with multi-omics, replicated across cell and tissue types, single lab","pmids":["37998397"],"is_preprint":false},{"year":2025,"finding":"BBS1 knockout leads to altered phosphorylation of TGF-β pathway components; network analysis identifies CDK2 as a central kinase in the BBS1 KO interactome, implicating BBS1 in regulation of TGF-β signaling and extracellular matrix regulation.","method":"CRISPR-CAS9 BBS1 KO; phosphoproteomics; network diffusion analysis; protein interaction mapping","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 3 — phosphoproteomics in KO cells with computational pathway analysis, no direct enzymatic or binding validation","pmids":["41193622"],"is_preprint":false},{"year":2024,"finding":"BBS1 knockout in retinal epithelial cells causes delayed transferrin internalization and increased recycling of TGFBR1 (rather than degradation), promoting EMT with increased cell migration and reduced proliferation after TGF-β stimulation; this contrasts with BBS4 KO which promotes receptor degradation, indicating BBS1 specifically regulates the recycling arm of receptor endocytic trafficking.","method":"BBS1 KO cell lines; transferrin uptake assay; TGFBR1 recycling vs. degradation assay; EMT marker analysis; migration and proliferation assays","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 + Weak — preprint, single lab, functional assays without reconstitution or structural validation","pmids":[],"is_preprint":true}],"current_model":"BBS1 is a core subunit of the BBSome octameric complex that mediates its translocation from pericentriolar satellites (where BBS4 nucleates assembly) to the ciliary base, where it facilitates ARL6/BBS3-dependent membrane recruitment and retrograde trafficking of ciliary GPCRs (including Smoothened and GPR161) out of cilia; additionally, BBS1 regulates BBSome complex stability, photoreceptor outer segment lipid homeostasis (particularly cholesterol), and non-ciliary functions including centrosome polarization toward the T cell immune synapse via coupling the 19S proteasome to dynein for centrosomal F-actin clearance, and regulation of TGFBR1 endocytic recycling."},"narrative":{"teleology":[{"year":2002,"claim":"Identifying BBS1 as the most frequently mutated gene in Bardet-Biedl syndrome established it as a central locus in ciliopathy pathogenesis and showed that a single missense variant (M390R) accounts for most BBS1 disease alleles.","evidence":"Positional cloning and mutational analysis in BBS families","pmids":["12118255"],"confidence":"High","gaps":["Protein function unknown","Subcellular localization undetermined","No interacting partners identified"]},{"year":2003,"claim":"Demonstrating that BBS1 genetically interacts with all other known BBS loci in oligogenic inheritance patterns, and that disease-causing mutations mislocalize the protein, established that BBS proteins operate in a shared functional pathway requiring correct subcellular targeting.","evidence":"Genetic epistasis analysis across 259 BBS families; fluorescence microscopy of mutant vs. wild-type BBS1 in transfected mammalian cells","pmids":["12677556","12837689"],"confidence":"High","gaps":["Biochemical nature of the shared pathway unknown","Direct physical interactions among BBS proteins not yet shown","Ciliary relevance not established"]},{"year":2018,"claim":"BBS1 knockout revealed its essential role in retrograde trafficking of ciliary GPCRs (Smoothened, GPR161) and showed that BBS1 is required for ciliary entry of other BBSome subunits and ARL6, with the ARL6-BBS1 interaction reinforced by BBS9, defining BBS1 as central to BBSome assembly and ARL6-mediated membrane recruitment.","evidence":"BBS1 KO cell lines with rescue by wild-type vs. BBS9-binding-deficient BBS1; immunofluorescence for ciliary GPCRs; Co-IP for ARL6-BBS1-BBS9 interaction","pmids":["29590217"],"confidence":"High","gaps":["Structural basis of BBS1-ARL6-BBS9 ternary interaction not resolved","Whether BBS1 directly contacts cargo GPCRs or acts through adaptor proteins unknown"]},{"year":2020,"claim":"Establishing that BBSome assembly is sequential — with BBS4 nucleating a pre-BBSome at pericentriolar satellites and BBS1 then mediating translocation to the ciliary base — resolved the spatiotemporal order of complex biogenesis and assigned BBS1 a specific post-assembly trafficking role.","evidence":"Fluorescently tagged BBSome subunits in individual KO cell lines; FRAP, FCS, expansion microscopy, biochemical fractionation","pmids":["32759308"],"confidence":"High","gaps":["Motor or transport machinery used by BBS1 for satellite-to-ciliary-base translocation not identified","Whether BBS1 acts catalytically or as a structural scaffold for translocation unknown"]},{"year":2021,"claim":"Discovery that BBS1 promotes centrosome polarization toward the T cell immune synapse by coupling the 19S proteasome regulatory subunit to dynein for centrosomal F-actin and WASH1 clearance revealed a non-ciliary, proteasome-dependent function for BBS1.","evidence":"BBS1 knockdown/knockout in T cells; Co-IP for BBS1-dynein-19S proteasome; immunofluorescence; proteasome inhibitor experiments","pmids":["34423835"],"confidence":"Medium","gaps":["Single lab finding; independent replication pending","Whether this function requires the intact BBSome or BBS1 alone not established","Structural basis for BBS1-dynein-proteasome coupling unknown"]},{"year":2022,"claim":"Bbs1 loss in zebrafish photoreceptors demonstrated that BBS1 maintains BBSome stability and outer segment lipid homeostasis — particularly cholesterol levels — with functional visual deficits preceding structural degeneration, providing a molecular link between ciliary trafficking defects and retinal disease.","evidence":"bbs1 zebrafish mutant; quantitative proteomics and lipidomics on outer segments; electroretinography","pmids":["35277505"],"confidence":"High","gaps":["Whether cholesterol accumulation is a direct consequence of impaired lipid transporter trafficking or secondary metabolic dysregulation not resolved","Mechanism of BBS1-dependent lipid homeostasis not defined"]},{"year":2022,"claim":"T cell-specific Bbs1 deletion impaired CD4 T cell-mediated wound closure and altered CD4/CD8 ratios under inflammatory stimulation, extending BBS1 function to adaptive immune regulation in vivo.","evidence":"Conditional Bbs1 KO mice; flow cytometry; wound closure and Imiquimod treatment models","pmids":["36534590"],"confidence":"Medium","gaps":["Whether immune phenotype is cilium-dependent or reflects the non-ciliary BBS1 function in T cells not determined","Mechanism linking BBS1 loss to altered CD4/CD8 ratios unknown"]},{"year":2023,"claim":"BBS1 loss in renal collecting duct cells caused failure to suppress mesenchymal gene programs during differentiation, with EMT gene dysregulation confirmed across BBS mutant mouse hypothalamus and patient fibroblasts, establishing EMT suppression as a general BBS1-dependent process across tissues.","evidence":"CRISPR Bbs1 KO IMCD3 lines; transcriptomics across cell lines, mouse tissue, and patient fibroblasts","pmids":["37998397"],"confidence":"Medium","gaps":["Direct mechanism by which BBS1/BBSome suppresses EMT unknown","Whether EMT phenotype is cilium-dependent or reflects altered receptor trafficking not distinguished"]},{"year":null,"claim":"Key unresolved questions include the structural basis of BBS1 within the BBSome at atomic resolution during cargo engagement, the motor/adaptor machinery by which BBS1 drives satellite-to-ciliary-base translocation, and the extent to which BBS1's non-ciliary functions (immune synapse polarization, EMT regulation, TGFBR1 recycling) are BBSome-dependent versus independent.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of BBS1 in complex with ARL6 and cargo","Motor driving BBS1-mediated translocation from satellites to ciliary base unidentified","Cilium-dependent vs. cilium-independent functions not genetically separated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[4,5,6]}],"localization":[{"term_id":"GO:0005929","term_label":"cilium","supporting_discovery_ids":[4,5]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[5,6]}],"pathway":[{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[4,5]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[4,7,10]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6,9]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[4,5]}],"complexes":["BBSome"],"partners":["BBS2","BBS4","BBS7","BBS9","ARL6","WASH1"],"other_free_text":[]},"mechanistic_narrative":"BBS1 is a core subunit of the BBSome, an octameric ciliary trafficking complex, and is the most commonly mutated gene in Bardet-Biedl syndrome [PMID:12118255]. BBS1 mediates the translocation of the assembled BBSome from pericentriolar satellites to the ciliary base, where it facilitates ARL6/BBS3-dependent membrane recruitment and retrograde trafficking of ciliary GPCRs such as Smoothened and GPR161 [PMID:29590217, PMID:32759308]. Loss of BBS1 destabilizes the BBSome complex, causing accumulation of membrane-associated proteins and cholesterol in photoreceptor outer segments leading to early visual dysfunction, and disrupts epithelial identity by failing to suppress epithelial-to-mesenchymal transition in renal and other cell types [PMID:35277505, PMID:37998397]. Beyond ciliary functions, BBS1 promotes centrosome polarization toward the T cell immune synapse by coupling the 19S proteasome to dynein for centrosomal F-actin clearance, and T cell-specific Bbs1 deletion impairs CD4 T cell-mediated wound healing [PMID:34423835, PMID:36534590]."},"prefetch_data":{"uniprot":{"accession":"Q8NFJ9","full_name":"BBSome complex member BBS1","aliases":["BBS2-like protein 2","Bardet-Biedl syndrome 1 protein"],"length_aa":593,"mass_kda":65.1,"function":"The BBSome complex is thought to function as a coat complex required for sorting of specific membrane proteins to the primary cilia. The BBSome complex is required for ciliogenesis but is dispensable for centriolar satellite function. This ciliogenic function is mediated in part by the Rab8 GDP/GTP exchange factor, which localizes to the basal body and contacts the BBSome. Rab8(GTP) enters the primary cilium and promotes extension of the ciliary membrane. Firstly the BBSome associates with the ciliary membrane and binds to RAB3IP/Rabin8, the guanosyl exchange factor (GEF) for Rab8 and then the Rab8-GTP localizes to the cilium and promotes docking and fusion of carrier vesicles to the base of the ciliary membrane. The BBSome complex, together with the LTZL1, controls SMO ciliary trafficking and contributes to the sonic hedgehog (SHH) pathway regulation. Required for proper BBSome complex assembly and its ciliary localization (PubMed:17574030, PubMed:22072986). Plays a role in olfactory cilium biogenesis/maintenance and trafficking (By similarity)","subcellular_location":"Cell projection, cilium membrane; Cytoplasm; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriolar satellite","url":"https://www.uniprot.org/uniprotkb/Q8NFJ9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BBS1","classification":"Not Classified","n_dependent_lines":12,"n_total_lines":1208,"dependency_fraction":0.009933774834437087},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/BBS1","total_profiled":1310},"omim":[{"mim_id":"620505","title":"INTRAFLAGELLAR TRANSPORT 22; IFT22","url":"https://www.omim.org/entry/620505"},{"mim_id":"619471","title":"BARDET-BIEDL SYNDROME 20; BBS20","url":"https://www.omim.org/entry/619471"},{"mim_id":"617406","title":"BARDET-BIEDL SYNDROME 21; BBS21","url":"https://www.omim.org/entry/617406"},{"mim_id":"617119","title":"BARDET-BIEDL SYNDROME 22; BBS22","url":"https://www.omim.org/entry/617119"},{"mim_id":"616629","title":"SENIOR-LOKEN SYNDROME 9; SLSN9","url":"https://www.omim.org/entry/616629"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Midbody","reliability":"Uncertain"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BBS1"},"hgnc":{"alias_symbol":["FLJ23590"],"prev_symbol":[]},"alphafold":{"accession":"Q8NFJ9","domains":[{"cath_id":"2.130.10.10","chopping":"25-129_199-403","consensus_level":"medium","plddt":93.9274,"start":25,"end":403},{"cath_id":"-","chopping":"134-191","consensus_level":"high","plddt":90.5493,"start":134,"end":191},{"cath_id":"2.60.40.1230","chopping":"479-584","consensus_level":"high","plddt":91.2609,"start":479,"end":584}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NFJ9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NFJ9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8NFJ9-F1-predicted_aligned_error_v6.png","plddt_mean":89.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BBS1","jax_strain_url":"https://www.jax.org/strain/search?query=BBS1"},"sequence":{"accession":"Q8NFJ9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8NFJ9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8NFJ9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8NFJ9"}},"corpus_meta":[{"pmid":"12118255","id":"PMC_12118255","title":"Identification 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Advances in ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/31997113","citation_count":4,"is_preprint":false},{"pmid":"35692835","id":"PMC_35692835","title":"Case Report: Identification Pathogenic Abnormal Splicing of BBS1 Causing Bardet-Biedl Syndrome Type I (BBS1) due to Missense Mutation.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35692835","citation_count":3,"is_preprint":false},{"pmid":"34262361","id":"PMC_34262361","title":"Retinitis Pigmentosa and Polydactyly in a Patient with a Heterozygous Mutation on the BBS1 Gene.","date":"2021","source":"International medical case reports journal","url":"https://pubmed.ncbi.nlm.nih.gov/34262361","citation_count":3,"is_preprint":false},{"pmid":"36534590","id":"PMC_36534590","title":"T cell-specific deficiency in BBSome component BBS1 interferes with selective immune responses.","date":"2022","source":"American journal of physiology. Regulatory, integrative and comparative physiology","url":"https://pubmed.ncbi.nlm.nih.gov/36534590","citation_count":2,"is_preprint":false},{"pmid":"37998397","id":"PMC_37998397","title":"De-Suppression of Mesenchymal Cell Identities and Variable Phenotypic Outcomes Associated with Knockout of Bbs1.","date":"2023","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/37998397","citation_count":1,"is_preprint":false},{"pmid":"35695966","id":"PMC_35695966","title":"Lethal neonatal respiratory failure due to biallelic variants in BBS1 and monoallelic variant in TTC21B.","date":"2022","source":"Pediatric nephrology (Berlin, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/35695966","citation_count":1,"is_preprint":false},{"pmid":"39618083","id":"PMC_39618083","title":"Novel BBS1 deletion and BBS9 nonsense pathogenic variant in Bardet-Biedl syndrome.","date":"2024","source":"Ophthalmic genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39618083","citation_count":1,"is_preprint":false},{"pmid":"30142598","id":"PMC_30142598","title":"Generation of induced pluripotent stem cells, KCi001-A derived from a Bardet-Biedl syndrome patient compound heterozygous for the BBS1 variants c.1169T>G/c.1135G>C.","date":"2018","source":"Stem cell research","url":"https://pubmed.ncbi.nlm.nih.gov/30142598","citation_count":1,"is_preprint":false},{"pmid":"40923755","id":"PMC_40923755","title":"Genomic Analysis for the Safety Assessment of a Potential Probiotic Strain Pediococcus pentosaceus BBS1 Isolated From Lao Fermented Bamboo Shoots (Nor Mai Som).","date":"2025","source":"MicrobiologyOpen","url":"https://pubmed.ncbi.nlm.nih.gov/40923755","citation_count":0,"is_preprint":false},{"pmid":"42022048","id":"PMC_42022048","title":"Genetic and Phenotypic Characterization of a Large Cohort of Patients with BBS1-Retinopathy.","date":"2026","source":"Ophthalmology science","url":"https://pubmed.ncbi.nlm.nih.gov/42022048","citation_count":0,"is_preprint":false},{"pmid":"34792930","id":"PMC_34792930","title":"Compound Heterozygous Mutations in the BBS-1 Gene and its Clinical Presentation: A Case Report.","date":"2021","source":"Puerto Rico health sciences journal","url":"https://pubmed.ncbi.nlm.nih.gov/34792930","citation_count":0,"is_preprint":false},{"pmid":"41193622","id":"PMC_41193622","title":"Phosphoproteomic profiling highlights CDC42 and CDK2 as key players in the regulation of the TGF-β pathway in ALMS1 and BBS1 knockout models.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41193622","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.29.691277","title":"Intraflagellar transport-20 coiled-coil domain mediates the channelrhodopsins trafficking to the cilia in  <i>Chlamydomonas reinhardtii</i>","date":"2025-12-01","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.29.691277","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.10.23.619933","title":"Depletion of BBSome Subunits Alters Receptor Endocytosis and Promotes EMT via TGF-β Signaling","date":"2024-10-24","source":"bioRxiv","url":"https://doi.org/10.1101/2024.10.23.619933","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":21334,"output_tokens":2956,"usd":0.054171},"stage2":{"model":"claude-opus-4-6","input_tokens":6325,"output_tokens":2388,"usd":0.136988},"total_usd":0.191159,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"BBS1 was identified as the gene most commonly mutated in Bardet-Biedl syndrome, with a missense mutation (M390R) accounting for the majority of BBS1 cases; the gene product was shown to be highly conserved between mice and humans.\",\n      \"method\": \"Positional cloning, mutational analysis, sequence conservation analysis\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — foundational positional cloning study with mutational validation, replicated across multiple subsequent studies\",\n      \"pmids\": [\"12118255\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"BBS1 shares structural features (a conserved functional domain) with BBS2 and BBS7, suggesting these three proteins participate in a common functional pathway relevant to BBS pathogenesis.\",\n      \"method\": \"Phylogenetic and genomic comparative analysis, motif-based identification\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — computational/sequence similarity analysis only, no direct biochemical validation\",\n      \"pmids\": [\"12567324\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Introduction of a BBS1 missense mutation into mammalian cells causes dramatic mislocalization of the BBS1 protein compared to wild-type, indicating the mutation disrupts normal subcellular targeting.\",\n      \"method\": \"Transfection of mutant BBS1 constructs into mammalian cells, fluorescence microscopy for localization\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single cell-based localization experiment with mutant vs. wild-type comparison, single lab\",\n      \"pmids\": [\"12837689\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"BBS1 participates in oligogenic/non-Mendelian inheritance, genetically interacting with mutations at each of the other known BBS loci (BBS2, BBS4, BBS6, BBS7) to cause or modulate disease, demonstrating functional genetic interactions among BBS proteins.\",\n      \"method\": \"Genetic epistasis analysis, mutational screening of 259 BBS families, statistical modeling\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — large-scale genetic epistasis study replicated across multiple families and labs\",\n      \"pmids\": [\"12677556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"BBS1 is required for retrograde trafficking of ciliary GPCRs (Smoothened and GPR161) out of cilia; BBS1 knockout cells show defects in ciliary entry of other BBSome subunits (BBS2, BBS7, BBS9) and ARL6, and the trafficking defect is rescued by wild-type BBS1 but not by a BBS9-binding-deficient BBS1 mutant. The ARL6/BBS3-BBS1 interaction is reinforced by BBS9, indicating BBS1 is central to BBSome assembly and ARL6-mediated membrane recruitment.\",\n      \"method\": \"BBS1 knockout cell lines, rescue with wild-type vs. mutant BBS1, immunofluorescence microscopy for ciliary GPCR localization, Co-IP for ARL6-BBS1-BBS9 interaction\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO with defined phenotype, reciprocal interaction assays, structure-function mutagenesis rescue experiment\",\n      \"pmids\": [\"29590217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BBSome assembly is a sequential process in which BBS4 nucleates a pre-BBSome at pericentriolar satellites, followed by BBS1-mediated translocation of the assembled BBSome to the ciliary base. BBS1 is required for the ciliary base localization step of BBSome biogenesis.\",\n      \"method\": \"Library of human cell lines deficient in individual BBSome subunits expressing fluorescently tagged subunits; biochemical fractionation, FRAP, fluorescence correlation spectroscopy, expansion microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal quantitative microscopy methods in defined KO cell lines, single lab\",\n      \"pmids\": [\"32759308\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"BBS1 controls centrosome polarization toward the immune synapse in T cells by promoting clearance of centrosomal F-actin and its regulator WASH1 via proteasome-dependent degradation, coupling the 19S proteasome regulatory subunit to the microtubule motor dynein for transport to the centrosome.\",\n      \"method\": \"BBS1 knockdown/knockout in T cells, immunofluorescence for centrosome position and F-actin, Co-IP for BBS1-dynein-19S proteasome interactions, proteasome inhibitor experiments\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — defined cellular phenotype with mechanistic pathway placement, but single lab\",\n      \"pmids\": [\"34423835\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Bbs1 loss in zebrafish disrupts BBSome complex stability and leads to accumulation of membrane-associated proteins (particularly those involved in lipid homeostasis) in photoreceptor outer segments, resulting in elevated outer segment cholesterol content and early visual deficits preceding structural degeneration.\",\n      \"method\": \"bbs1 zebrafish mutant; quantitative proteomics and lipidomics on isolated outer segment-enriched samples; electroretinography for functional assessment\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — ortholog in zebrafish (consistent function), quantitative proteomics + lipidomics + functional ERG readout in the same study\",\n      \"pmids\": [\"35277505\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Ectopic expression of wild-type human BBS1 driven by the CAG promoter rescues male infertility (spermatozoa flagella assembly) but not retinal degeneration in Bbs1-M390R knock-in mice, indicating tissue-specific requirements for BBS1 expression levels.\",\n      \"method\": \"Transgenic mouse cross onto Bbs1M390R/M390R background; fertility testing; electroretinography; optical coherence tomography; immunohistochemistry; qRT-PCR for tissue expression\",\n      \"journal\": \"Gene therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo rescue experiment with multiple functional readouts, single lab\",\n      \"pmids\": [\"33664503\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"T cell-specific deletion of Bbs1 impairs CD4 T cell-mediated skin wound closure and alters splenic CD4/CD8 ratios upon Imiquimod stimulation, demonstrating a functional role for BBS1/BBSome in selective T cell immune responses.\",\n      \"method\": \"T cell-specific Bbs1 conditional knockout mice; flow cytometry; wound closure assay; Imiquimod treatment model\",\n      \"journal\": \"American journal of physiology. Regulatory, integrative and comparative physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with defined cellular phenotype, single lab\",\n      \"pmids\": [\"36534590\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"BBS1 loss in renal collecting duct IMCD3 cells leads to failure to suppress mesenchymal cell identities (epithelial-to-mesenchymal transition) as cells differentiate, associated with loss of epithelial markers and tight junction formation; transcriptomic analysis of BBS mutant mouse hypothalamus and BBS patient fibroblasts confirms dysregulation of EMT genes as a general feature across tissues.\",\n      \"method\": \"CRISPR-edited clonal IMCD3 Bbs1 KO cell lines; phenotypic screen; multi-omics (transcriptomics); analysis of mouse hypothalamic preparations and patient fibroblasts\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — CRISPR KO with multi-omics, replicated across cell and tissue types, single lab\",\n      \"pmids\": [\"37998397\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"BBS1 knockout leads to altered phosphorylation of TGF-β pathway components; network analysis identifies CDK2 as a central kinase in the BBS1 KO interactome, implicating BBS1 in regulation of TGF-β signaling and extracellular matrix regulation.\",\n      \"method\": \"CRISPR-CAS9 BBS1 KO; phosphoproteomics; network diffusion analysis; protein interaction mapping\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — phosphoproteomics in KO cells with computational pathway analysis, no direct enzymatic or binding validation\",\n      \"pmids\": [\"41193622\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"BBS1 knockout in retinal epithelial cells causes delayed transferrin internalization and increased recycling of TGFBR1 (rather than degradation), promoting EMT with increased cell migration and reduced proliferation after TGF-β stimulation; this contrasts with BBS4 KO which promotes receptor degradation, indicating BBS1 specifically regulates the recycling arm of receptor endocytic trafficking.\",\n      \"method\": \"BBS1 KO cell lines; transferrin uptake assay; TGFBR1 recycling vs. degradation assay; EMT marker analysis; migration and proliferation assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 + Weak — preprint, single lab, functional assays without reconstitution or structural validation\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"BBS1 is a core subunit of the BBSome octameric complex that mediates its translocation from pericentriolar satellites (where BBS4 nucleates assembly) to the ciliary base, where it facilitates ARL6/BBS3-dependent membrane recruitment and retrograde trafficking of ciliary GPCRs (including Smoothened and GPR161) out of cilia; additionally, BBS1 regulates BBSome complex stability, photoreceptor outer segment lipid homeostasis (particularly cholesterol), and non-ciliary functions including centrosome polarization toward the T cell immune synapse via coupling the 19S proteasome to dynein for centrosomal F-actin clearance, and regulation of TGFBR1 endocytic recycling.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"BBS1 is a core subunit of the BBSome, an octameric ciliary trafficking complex, and is the most commonly mutated gene in Bardet-Biedl syndrome [PMID:12118255]. BBS1 mediates the translocation of the assembled BBSome from pericentriolar satellites to the ciliary base, where it facilitates ARL6/BBS3-dependent membrane recruitment and retrograde trafficking of ciliary GPCRs such as Smoothened and GPR161 [PMID:29590217, PMID:32759308]. Loss of BBS1 destabilizes the BBSome complex, causing accumulation of membrane-associated proteins and cholesterol in photoreceptor outer segments leading to early visual dysfunction, and disrupts epithelial identity by failing to suppress epithelial-to-mesenchymal transition in renal and other cell types [PMID:35277505, PMID:37998397]. Beyond ciliary functions, BBS1 promotes centrosome polarization toward the T cell immune synapse by coupling the 19S proteasome to dynein for centrosomal F-actin clearance, and T cell-specific Bbs1 deletion impairs CD4 T cell-mediated wound healing [PMID:34423835, PMID:36534590].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Identifying BBS1 as the most frequently mutated gene in Bardet-Biedl syndrome established it as a central locus in ciliopathy pathogenesis and showed that a single missense variant (M390R) accounts for most BBS1 disease alleles.\",\n      \"evidence\": \"Positional cloning and mutational analysis in BBS families\",\n      \"pmids\": [\"12118255\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Protein function unknown\", \"Subcellular localization undetermined\", \"No interacting partners identified\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrating that BBS1 genetically interacts with all other known BBS loci in oligogenic inheritance patterns, and that disease-causing mutations mislocalize the protein, established that BBS proteins operate in a shared functional pathway requiring correct subcellular targeting.\",\n      \"evidence\": \"Genetic epistasis analysis across 259 BBS families; fluorescence microscopy of mutant vs. wild-type BBS1 in transfected mammalian cells\",\n      \"pmids\": [\"12677556\", \"12837689\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Biochemical nature of the shared pathway unknown\", \"Direct physical interactions among BBS proteins not yet shown\", \"Ciliary relevance not established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"BBS1 knockout revealed its essential role in retrograde trafficking of ciliary GPCRs (Smoothened, GPR161) and showed that BBS1 is required for ciliary entry of other BBSome subunits and ARL6, with the ARL6-BBS1 interaction reinforced by BBS9, defining BBS1 as central to BBSome assembly and ARL6-mediated membrane recruitment.\",\n      \"evidence\": \"BBS1 KO cell lines with rescue by wild-type vs. BBS9-binding-deficient BBS1; immunofluorescence for ciliary GPCRs; Co-IP for ARL6-BBS1-BBS9 interaction\",\n      \"pmids\": [\"29590217\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of BBS1-ARL6-BBS9 ternary interaction not resolved\", \"Whether BBS1 directly contacts cargo GPCRs or acts through adaptor proteins unknown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Establishing that BBSome assembly is sequential — with BBS4 nucleating a pre-BBSome at pericentriolar satellites and BBS1 then mediating translocation to the ciliary base — resolved the spatiotemporal order of complex biogenesis and assigned BBS1 a specific post-assembly trafficking role.\",\n      \"evidence\": \"Fluorescently tagged BBSome subunits in individual KO cell lines; FRAP, FCS, expansion microscopy, biochemical fractionation\",\n      \"pmids\": [\"32759308\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Motor or transport machinery used by BBS1 for satellite-to-ciliary-base translocation not identified\", \"Whether BBS1 acts catalytically or as a structural scaffold for translocation unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Discovery that BBS1 promotes centrosome polarization toward the T cell immune synapse by coupling the 19S proteasome regulatory subunit to dynein for centrosomal F-actin and WASH1 clearance revealed a non-ciliary, proteasome-dependent function for BBS1.\",\n      \"evidence\": \"BBS1 knockdown/knockout in T cells; Co-IP for BBS1-dynein-19S proteasome; immunofluorescence; proteasome inhibitor experiments\",\n      \"pmids\": [\"34423835\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab finding; independent replication pending\", \"Whether this function requires the intact BBSome or BBS1 alone not established\", \"Structural basis for BBS1-dynein-proteasome coupling unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Bbs1 loss in zebrafish photoreceptors demonstrated that BBS1 maintains BBSome stability and outer segment lipid homeostasis — particularly cholesterol levels — with functional visual deficits preceding structural degeneration, providing a molecular link between ciliary trafficking defects and retinal disease.\",\n      \"evidence\": \"bbs1 zebrafish mutant; quantitative proteomics and lipidomics on outer segments; electroretinography\",\n      \"pmids\": [\"35277505\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether cholesterol accumulation is a direct consequence of impaired lipid transporter trafficking or secondary metabolic dysregulation not resolved\", \"Mechanism of BBS1-dependent lipid homeostasis not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"T cell-specific Bbs1 deletion impaired CD4 T cell-mediated wound closure and altered CD4/CD8 ratios under inflammatory stimulation, extending BBS1 function to adaptive immune regulation in vivo.\",\n      \"evidence\": \"Conditional Bbs1 KO mice; flow cytometry; wound closure and Imiquimod treatment models\",\n      \"pmids\": [\"36534590\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether immune phenotype is cilium-dependent or reflects the non-ciliary BBS1 function in T cells not determined\", \"Mechanism linking BBS1 loss to altered CD4/CD8 ratios unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"BBS1 loss in renal collecting duct cells caused failure to suppress mesenchymal gene programs during differentiation, with EMT gene dysregulation confirmed across BBS mutant mouse hypothalamus and patient fibroblasts, establishing EMT suppression as a general BBS1-dependent process across tissues.\",\n      \"evidence\": \"CRISPR Bbs1 KO IMCD3 lines; transcriptomics across cell lines, mouse tissue, and patient fibroblasts\",\n      \"pmids\": [\"37998397\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct mechanism by which BBS1/BBSome suppresses EMT unknown\", \"Whether EMT phenotype is cilium-dependent or reflects altered receptor trafficking not distinguished\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of BBS1 within the BBSome at atomic resolution during cargo engagement, the motor/adaptor machinery by which BBS1 drives satellite-to-ciliary-base translocation, and the extent to which BBS1's non-ciliary functions (immune synapse polarization, EMT regulation, TGFBR1 recycling) are BBSome-dependent versus independent.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of BBS1 in complex with ARL6 and cargo\", \"Motor driving BBS1-mediated translocation from satellites to ciliary base unidentified\", \"Cilium-dependent vs. cilium-independent functions not genetically separated\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [4, 5, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005929\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [5, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [4, 7, 10]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6, 9]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"complexes\": [\"BBSome\"],\n    \"partners\": [\"BBS2\", \"BBS4\", \"BBS7\", \"BBS9\", \"ARL6\", \"WASH1\"],\n    \"other_free_text\": []\n  }\n}\n```"}