Affinage

BBS1

BBSome complex member BBS1 · UniProt Q8NFJ9

Length
593 aa
Mass
65.1 kDa
Annotated
2026-06-09
38 papers in source corpus 11 papers cited in narrative 12 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/6 claims corpus-supported (83%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

BBS1 is an essential core subunit of the BBSome, the multi-subunit complex that governs selective protein trafficking at the primary cilium (PMID:29590217, PMID:32759308). During BBSome biogenesis, BBS1 acts at a defined late step, mediating translocation of the assembled complex from pericentriolar satellites to the ciliary base, downstream of BBS4-dependent nucleation (PMID:32759308). At the cilium, BBS1 is required for retrograde export of signaling GPCRs including Smoothened and GPR161, and its loss blocks ciliary entry of other BBSome subunits (BBS2, BBS7, BBS9) and of ARL6; the ARL6–BBS1 interaction is reinforced by BBS9, and a BBS1 mutant unable to bind BBS9 fails to rescue trafficking, establishing BBS9 binding as a functional requirement (PMID:29590217). In photoreceptors, BBS1 maintains outer-segment homeostasis, preventing accumulation of membrane-associated lipid-homeostasis proteins and cholesterol that drives early visual deficits (PMID:35277505). Beyond the cilium, BBS1 also operates in vesicular trafficking and signaling control: it directs T cell centrosome polarization to the immune synapse by coupling the 19S proteasome to dynein for clearance of centrosomal F-actin and its regulator WASH1 (PMID:34423835), supports T cell-mediated skin repair (PMID:36534590), and in epithelial cells suppresses epithelial-to-mesenchymal transition while regulating TGFBR1 recycling (PMID:37998397). The disease-associated M390R missense mutation causes mislocalization of BBS1 protein, linking loss of correct localization to Bardet-Biedl syndrome pathology (PMID:12837689), and rescue of the M390R mouse demonstrates tissue-specific requirements, with transgenic BBS1 correcting spermatozoa flagellar defects but not retinal degeneration (PMID:33664503).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2003 Medium

    Established the first mechanistic link between a BBS1 disease mutation and cellular pathology, showing the recurrent M390R substitution disrupts proper protein localization.

    Evidence transfection of wild-type and mutant BBS1 in mammalian cells with immunofluorescence

    PMID:12837689

    Open questions at the time
    • does not define the normal subcellular destination of BBS1
    • single localization experiment without complex-context readout
  2. 2003 Low

    Defined a shared domain architecture among BBS1, BBS2 and BBS7, framing BBS1 as part of a structurally related protein family before complex assembly was understood.

    Evidence comparative phylogenetic and genomic sequence analysis

    PMID:12567324

    Open questions at the time
    • computational only, no biochemical confirmation of function
    • does not establish physical interaction or complex membership
  3. 2018 High

    Demonstrated BBS1 is required for retrograde ciliary export of GPCRs and for ciliary entry of other BBSome subunits and ARL6, placing BBS1 at the center of BBSome-dependent ciliary cargo trafficking.

    Evidence BBS1 knockout cells with wild-type and BBS9-binding-deficient rescue, co-IP, immunofluorescence

    PMID:29590217

    Open questions at the time
    • does not resolve the molecular geometry of the ARL6-BBS1-BBS9 interaction
    • cargo selectivity rules for export not defined
  4. 2019 Medium

    Characterized a pathogenic splice-donor mutation as causing dual mis-splicing (exon skipping plus intron retention) and showed complementary RNA-based correction strategies, refining the molecular basis of one BBS1 allele.

    Evidence patient cell lines, engineered U1 snRNA, antisense oligonucleotides, RT-PCR splicing analysis

    PMID:31541798

    Open questions at the time
    • correction measured at RNA level, not protein restoration or functional rescue
    • applies to one specific splice allele
  5. 2020 High

    Resolved the order of BBSome biogenesis, assigning BBS1 a specific late role in translocating the complex from pericentriolar satellites to the ciliary base after BBS4-dependent nucleation.

    Evidence tagged-subunit cell lines deficient in individual subunits, FRAP, FCS, expansion microscopy, biochemistry

    PMID:32759308

    Open questions at the time
    • machinery driving the satellite-to-base translocation not identified
    • does not define how BBS1 is regulated during this step
  6. 2021 Medium

    Revealed a cilium-independent role: BBS1 couples the 19S proteasome to dynein to clear centrosomal F-actin and WASH1, enabling T cell centrosome polarization to the immune synapse.

    Evidence siRNA knockdown in T cells, reciprocal co-IP, proteasome inhibitor assays, immunofluorescence

    PMID:34423835

    Open questions at the time
    • direct binding interface between BBS1 and 19S/dynein not mapped
    • single lab, knockdown rather than knockout
  7. 2021 Medium

    Established that BBS1 requirements are tissue-specific, with transgenic BBS1 rescuing flagellar/fertility defects but not retinal degeneration in M390R mice.

    Evidence CAG-BBS1 transgene on Bbs1-M390R knock-in mice, ERG, OCT, fertility assays, histology

    PMID:33664503

    Open questions at the time
    • does not explain why retina is refractory to rescue
    • expression-level thresholds per tissue not quantified mechanistically
  8. 2022 High

    Linked BBS1 loss to photoreceptor lipid and protein homeostasis, showing cholesterol and membrane-protein accumulation in outer segments drives early visual deficits.

    Evidence bbs1 zebrafish mutant, outer-segment proteomics and lipidomics, visual assays, electron microscopy

    PMID:35277505

    Open questions at the time
    • mechanism connecting BBSome trafficking to cholesterol clearance not defined
    • primary cargo responsible for the lipid phenotype not pinpointed
  9. 2022 Medium

    Extended the T cell role in vivo, showing T cell-specific Bbs1 deletion impairs wound closure and alters CD4 T cell responses.

    Evidence T cell-conditional Bbs1 knockout mice, flow cytometry, imiquimod treatment, wound assays

    PMID:36534590

    Open questions at the time
    • molecular pathway connecting BBS1 to the altered CD4 responses not resolved
    • limited mechanistic depth beyond phenotype
  10. 2023 Medium

    Identified a role for BBS1 in maintaining epithelial identity, with loss promoting mesenchymal transition and tight-junction disruption across cell and tissue models.

    Evidence CRISPR KO IMCD3 clones, transcriptomics, immunofluorescence, multi-omics across mouse tissue and patient fibroblasts

    PMID:37998397

    Open questions at the time
    • direct molecular effector linking BBSome to EMT suppression unresolved
    • passage-dependence mechanism not explained
  11. 2024 Low

    Proposed a specific endocytic role, with BBS1 biasing TGFBR1 toward recycling rather than degradation to limit EMT, distinguishing it from BBS4.

    Evidence BBS1 KO retinal epithelial cells, transferrin internalization, TGFBR1 recycling/degradation, migration assays (preprint)

    Open questions at the time
    • preprint, not peer-reviewed
    • direct interaction of BBS1 with TGFBR1 or sorting machinery not shown
  12. 2025 Low

    Implicated CDK2 as a downstream node in TGF-β signaling deregulated upon BBS1 loss, connecting BBS1 to ECM-related phosphosignaling.

    Evidence CRISPR BBS1 KO, phosphoproteomics, network diffusion and PPI mapping

    PMID:41193622

    Open questions at the time
    • no direct biochemical validation of CDK2 involvement
    • causal link between BBS1 and CDK2 phosphorylation not established

Open questions

Synthesis pass · forward-looking unresolved questions
  • How BBS1 reconciles its canonical ciliary BBSome trafficking role with its cilium-independent functions in proteasome-dynein coupling and endocytic receptor sorting remains unresolved.
  • no unifying mechanism linking ciliary and non-ciliary roles
  • structural basis of BBS1 cargo and partner selection undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005215 transporter activity 2 GO:0060090 molecular adaptor activity 2
Localization
GO:0005815 microtubule organizing center 2 GO:0005929 cilium 2
Pathway
R-HSA-5653656 Vesicle-mediated transport 2 R-HSA-162582 Signal Transduction 1
Partners
ARL6BBS2BBS4BBS7BBS9
Complex memberships
BBSome

Evidence

Reading pass · 12 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 BBS1 is required for ciliary retrograde trafficking of 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 fail to export GPCRs. The ARL6-BBS1 interaction is reinforced by BBS9, and a BBS1 mutant lacking BBS9-binding ability cannot rescue the trafficking defect. BBS1 knockout cell lines, rescue experiments with wild-type and BBS9-binding-deficient BBS1 mutants, co-immunoprecipitation, immunofluorescence microscopy PloS one High 29590217
2020 BBSome assembly is a sequential process: BBS4 nucleates a pre-BBSome at pericentriolar satellites, followed by translocation to the ciliary base mediated by BBS1. BBS1 is required for the later step of BBSome translocation from satellites to the ciliary base. Fluorescent protein-tagged BBSome subunit cell lines deficient in individual subunits, FRAP, fluorescence correlation spectroscopy, expansion microscopy, biochemical assays The Journal of biological chemistry High 32759308
2021 BBS1 controls T cell centrosome polarization toward the immune synapse by promoting clearance of centrosomal F-actin and its positive regulator WASH1 in a proteasome-dependent manner. BBS1 couples the 19S proteasome regulatory subunit to the microtubule motor dynein for transport to the centrosome. siRNA knockdown of BBS1 in T cells, co-immunoprecipitation, immunofluorescence microscopy, proteasome inhibitor experiments Journal of cell science Medium 34423835
2022 Bbs1 loss in zebrafish disrupts BBSome-complex stability and leads to accumulation of membrane-associated proteins (especially those involved in lipid homeostasis) in photoreceptor outer segments, and increased outer segment cholesterol content, causing early visual deficits preceding photoreceptor morphological anomalies. bbs1 zebrafish mutant, quantitative proteomics and lipidomics on isolated outer segments, visual function assays, transmission electron microscopy Nature communications High 35277505
2003 A missense mutation in BBS1 (corresponding to M390R) causes dramatic mislocalization of the BBS1 protein in mammalian cells compared with wild-type, establishing a direct link between this mutation and protein mislocalization as a disease mechanism. Transfection of wild-type and mutant BBS1 constructs in mammalian cells, immunofluorescence microscopy Human molecular genetics Medium 12837689
2003 BBS1 shares structural features (overlapping motif-defined domains) with BBS2 and BBS7, defining a potential functional domain present in three BBS proteins; BBS1 and BBS7 are paralogous in domain architecture. Phylogenetic and genomic sequence analysis, comparative peptide sequence searches in dbEST and translated genome American journal of human genetics Low 12567324
2021 Ectopic expression of human BBS1 driven by the CAG promoter rescues male infertility (spermatozoa flagella defects) in Bbs1-M390R knock-in mice but does not rescue retinal degeneration, indicating tissue-specific requirements for BBS1 expression levels. Transgenic mouse model (CAG-BBS1 crossed onto Bbs1-M390R/M390R), electroretinography, OCT, fertility assays, qRT-PCR, immunohistochemistry Gene therapy Medium 33664503
2022 T cell-specific deletion of Bbs1 in mice impairs wound closure and alters CD4 T cell responses to imiquimod stimulation, demonstrating that the BBSome (via BBS1) plays a role in T cell-mediated skin repair and selective immune responses. T cell-conditional Bbs1 knockout mice, flow cytometry, imiquimod dermal treatment, wound closure assay American journal of physiology. Regulatory, integrative and comparative physiology Medium 36534590
2023 BBS1 loss-of-function in IMCD3 cells results in failure to suppress mesenchymal cell identity and disrupted epithelial markers/tight junction formation as passage number increases, suggesting BBS1/BBSome is required for maintenance of epithelial identity, with dysregulation of EMT genes also observed in BBS mouse hypothalamic tissue and patient fibroblasts. CRISPR KO clonal IMCD3 cell lines, phenotypic screen, transcriptomics, immunofluorescence, multi-omics Cells Medium 37998397
2024 BBS1 knockout cells show delayed transferrin internalisation and increased recycling of TGFBR1 (rather than degradation), promoting EMT and increased cell migration; this is distinct from BBS4 KO where receptor degradation is increased, indicating BBS1 specifically regulates receptor recycling versus degradation balance. BBS1 KO retinal epithelial cells (CRISPR), transferrin internalization assay, TGFBR1 recycling/degradation assays, EMT marker quantification, migration assay bioRxivpreprint Low
2025 In BBS1 KO cells, phosphoproteomic analysis identified CDK2 as a central node in deregulated TGF-β signaling, with BBS1 loss affecting phosphorylation of proteins involved in extracellular matrix regulation downstream of TGF-β. CRISPR-Cas9 BBS1 KO, phosphoproteomics, network diffusion analysis, protein-protein interaction mapping Scientific reports Low 41193622
2019 A BBS1 splice donor site mutation (c.479G>A) causes both exon 5 skipping and intron 5 retention; engineered U1 snRNA efficiently reverts exon skipping but not intron retention, while antisense oligonucleotides (AONs) block intron retention; combined treatment achieves highest correction of BBS1 splicing. Patient-derived cell lines with BBS1 splice mutation, lentiviral delivery of engineered U1 snRNA, AON treatment, RT-PCR splicing analysis Molecular therapy. Nucleic acids Medium 31541798

Source papers

Stage 0 corpus · 38 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2002 Identification of the gene (BBS1) most commonly involved in Bardet-Biedl syndrome, a complex human obesity syndrome. Nature genetics 268 12118255
2003 Genetic interaction of BBS1 mutations with alleles at other BBS loci can result in non-Mendelian Bardet-Biedl syndrome. American journal of human genetics 196 12677556
2003 Identification of a novel Bardet-Biedl syndrome protein, BBS7, that shares structural features with BBS1 and BBS2. American journal of human genetics 172 12567324
2003 Heterozygous mutations in BBS1, BBS2 and BBS6 have a potential epistatic effect on Bardet-Biedl patients with two mutations at a second BBS locus. Human molecular genetics 153 12837689
2012 BBS1 mutations in a wide spectrum of phenotypes ranging from nonsyndromic retinitis pigmentosa to Bardet-Biedl syndrome. Archives of ophthalmology (Chicago, Ill. : 1960) 103 23143442
2003 Evaluation of complex inheritance involving the most common Bardet-Biedl syndrome locus (BBS1). American journal of human genetics 93 12524598
2006 Retinal disease expression in Bardet-Biedl syndrome-1 (BBS1) is a spectrum from maculopathy to retina-wide degeneration. Investigative ophthalmology & visual science 66 17065520
2018 BBS1 is involved in retrograde trafficking of ciliary GPCRs in the context of the BBSome complex. PloS one 55 29590217
2008 A novel founder BBS1 mutation explains a unique high prevalence of Bardet-Biedl syndrome in the Faroe Islands. The British journal of ophthalmology 47 18669544
1999 Delineation of the critical interval of Bardet-Biedl syndrome 1 (BBS1) to a small region of 11q13, through linkage and haplotype analysis of 91 pedigrees. American journal of human genetics 40 10577921
2015 Targeted multi-gene panel testing for the diagnosis of Bardet Biedl syndrome: Identification of nine novel mutations across BBS1, BBS2, BBS4, BBS7, BBS9, BBS10 genes. European journal of medical genetics 39 26518167
2012 Phenotypic expression of Bardet-Biedl syndrome in patients homozygous for the common M390R mutation in the BBS1 gene. Vision research 37 22940089
1999 A founder effect in the newfoundland population reduces the Bardet-Biedl syndrome I (BBS1) interval to 1 cM. American journal of human genetics 37 10577922
2013 Exome sequencing identifies a novel and a recurrent BBS1 mutation in Pakistani families with Bardet-Biedl syndrome. Molecular vision 29 23559858
2022 Loss of the Bardet-Biedl protein Bbs1 alters photoreceptor outer segment protein and lipid composition. Nature communications 26 35277505
2020 The BBSome assembly is spatially controlled by BBS1 and BBS4 in human cells. The Journal of biological chemistry 24 32759308
2021 BBS1 branchpoint variant is associated with non-syndromic retinitis pigmentosa. Journal of medical genetics 22 33910932
2020 A BBS1 SVA F retrotransposon insertion is a frequent cause of Bardet-Biedl syndrome. Clinical genetics 22 33169370
2019 Combining Engineered U1 snRNA and Antisense Oligonucleotides to Improve the Treatment of a BBS1 Splice Site Mutation. Molecular therapy. Nucleic acids 20 31541798
2014 Novel RP1 mutations and a recurrent BBS1 variant explain the co-existence of two distinct retinal phenotypes in the same pedigree. BMC genetics 19 25494902
2013 The Leishmania major BBSome subunit BBS1 is essential for parasite virulence in the mammalian host. Molecular microbiology 17 23998526
1999 Evaluation and molecular characterization of EHD1, a candidate gene for Bardet-Biedl syndrome 1 (BBS1). Gene 15 10564830
2021 The Bardet-Biedl syndrome complex component BBS1 controls T cell polarity during immune synapse assembly. Journal of cell science 14 34423835
2008 Bardet-biedl syndrome: an atypical phenotype in brothers with a proven BBS1 mutation. Ophthalmic genetics 14 18766993
1998 A transcript map of an 800-kb region on human chromosome 11q13, part of the candidate region for SCA5 and BBS1. Human genetics 9 9921902
2021 Ectopic expression of BBS1 rescues male infertility, but not retinal degeneration, in a BBS1 mouse model. Gene therapy 4 33664503
2020 Novel biallelic splice-site BBS1 variants in Bardet-Biedle syndrome: a case report of the first Japanese patient. Documenta ophthalmologica. Advances in ophthalmology 4 31997113
2022 Case Report: Identification Pathogenic Abnormal Splicing of BBS1 Causing Bardet-Biedl Syndrome Type I (BBS1) due to Missense Mutation. Frontiers in genetics 3 35692835
2021 Retinitis Pigmentosa and Polydactyly in a Patient with a Heterozygous Mutation on the BBS1 Gene. International medical case reports journal 3 34262361
2023 De-Suppression of Mesenchymal Cell Identities and Variable Phenotypic Outcomes Associated with Knockout of Bbs1. Cells 2 37998397
2022 T cell-specific deficiency in BBSome component BBS1 interferes with selective immune responses. American journal of physiology. Regulatory, integrative and comparative physiology 2 36534590
2024 Novel BBS1 deletion and BBS9 nonsense pathogenic variant in Bardet-Biedl syndrome. Ophthalmic genetics 1 39618083
2022 Lethal neonatal respiratory failure due to biallelic variants in BBS1 and monoallelic variant in TTC21B. Pediatric nephrology (Berlin, Germany) 1 35695966
2018 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. Stem cell research 1 30142598
2026 Genetic and Phenotypic Characterization of a Large Cohort of Patients with BBS1-Retinopathy. Ophthalmology science 0 42022048
2025 Genomic Analysis for the Safety Assessment of a Potential Probiotic Strain Pediococcus pentosaceus BBS1 Isolated From Lao Fermented Bamboo Shoots (Nor Mai Som). MicrobiologyOpen 0 40923755
2025 Phosphoproteomic profiling highlights CDC42 and CDK2 as key players in the regulation of the TGF-β pathway in ALMS1 and BBS1 knockout models. Scientific reports 0 41193622
2021 Compound Heterozygous Mutations in the BBS-1 Gene and its Clinical Presentation: A Case Report. Puerto Rico health sciences journal 0 34792930

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