BBS1

UniProt ID: Q8NFJ9
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

BBS1 (Bardet-Biedl syndrome 1 protein) is a core subunit of the BBSome, an octameric, coat-like protein complex (BBS1, BBS2, BBS4, BBS5, BBS7, BBS8/TTC8, BBS9 and BBIP1/BBIP10) that is structurally related to COPI, COPII and clathrin coats. The BBSome acts as a cargo adaptor that sorts specific transmembrane proteins, notably ciliary G-protein-coupled receptors and Hedgehog-pathway components such as Smoothened, into and out of the primary cilium by coupling them to intraflagellar transport. BBS1 contributes a seven-bladed beta-propeller that provides a principal cargo-recognition surface and binds the GTP-loaded Arf-like GTPase ARL6/BBS3, which recruits the BBSome to the ciliary membrane. The BBSome cooperates with the Rab8 guanine-nucleotide exchange factor RAB3IP/Rabin8 to promote ciliary membrane biogenesis. BBS1 is predominantly found at the ciliary membrane and in the cytoplasm, with pools at the centrosome/basal body and centriolar satellites. Loss of BBS1 function causes Bardet-Biedl syndrome, an autosomal recessive ciliopathy featuring retinal degeneration, obesity, polydactyly, renal malformation, hypogenitalism and intellectual disability; BBS1 is the most commonly mutated BBS gene, with M390R the most frequent allele.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0034464 BBSome
IBA
GO_REF:0000033 		ACCEPT
Summary: BBSome membership is the central, defining feature of BBS1, supported by multiple direct experimental annotations (IDA) and phylogeny (IBA). This is a core annotation.
GO:0005813 centrosome
IBA
GO_REF:0000033 		ACCEPT
Summary: BBS1 and BBSome subunits localize at/near the centrosome and basal body, consistent with UniProt subcellular location and IDA (PMID:18762586). Accept as a supported localization, though the centrosome/satellite pool is staging rather than the primary site of cargo-coat action.
GO:0061512 protein localization to cilium
IBA
GO_REF:0000033 		ACCEPT
Summary: The core function of the BBSome is to sort membrane proteins to/from the cilium. This is well supported (IMP PMID:23943788; IBA) and represents a core BBS1 process.
GO:1905515 non-motile cilium assembly
IBA
GO_REF:0000033 		ACCEPT
Summary: BBS1/BBSome act on non-motile (primary/sensory) cilia and are required for ciliogenesis (IMP PMID:17574030, PMID:17980398). Non-motile cilium assembly is the appropriate, specific term.
GO:0005113 patched binding
IBA
GO_REF:0000033 		MARK AS OVER ANNOTATED
Summary: This MF is propagated by phylogeny from the experimental IPI annotation (PMID:22228099), which is a genetic-interaction / ciliary-accumulation study showing the BBSome regulates SMO and PTCH1 ciliary levels, not a direct BBS1-PTCH1 binding assay. The binding claim is over-interpreted; the underlying biology (regulation of Hedgehog cargo trafficking) is better captured by ciliary trafficking / Hedgehog regulation terms.
Reason: Direct patched binding by BBS1 is not demonstrated; the source evidence shows regulation of PTCH1 ciliary localization via the BBSome, not a molecular binding function.
GO:0005119 smoothened binding
IBA
GO_REF:0000033 		MARK AS OVER ANNOTATED
Summary: As with patched binding, this is propagated from PMID:22228099, where loss of BBS genes causes SMO accumulation in cilia and reduced Shh response. The BBSome regulates SMO ciliary trafficking; direct BBS1-SMO binding is not established. Over-annotation of a trafficking role as a binding function.
Reason: Evidence supports BBSome-dependent regulation of Smoothened ciliary localization, not a direct molecular binding activity of BBS1.
GO:0005930 axoneme
IBA
GO_REF:0000033 		KEEP AS NON CORE
Summary: The BBSome acts mainly at the ciliary membrane and ciliary base/transition zone and moves along the axoneme with IFT; an axonemal pool exists but is not the primary functional site for BBS1. Retain as a non-core localization.
Reason: BBSome cargo-coat function is centered on the ciliary membrane; axonemal presence reflects IFT-coupled movement rather than a distinct core site of action.
GO:0001895 retina homeostasis
IEA
GO_REF:0000117 		KEEP AS NON CORE
Summary: BBS1 mutations cause retinal degeneration and photoreceptor loss, so this is biologically plausible as a downstream physiological consequence of ciliary dysfunction. It is not a core molecular/cellular function of BBS1.
Reason: Retina homeostasis is a tissue-level consequence of BBS1 loss (photoreceptor cilium defects), not a direct core function.
GO:0005737 cytoplasm
IEA
GO_REF:0000044 		ACCEPT
Summary: Consistent with UniProt subcellular location (Cytoplasm). A cytoplasmic pool of BBS1/BBSome exists prior to ciliary recruitment. Accept, though more specific terms (cytosol, ciliary membrane) are also annotated.
GO:0008104 intracellular protein localization
IEA
GO_REF:0000117 		MODIFY
Summary: This is an over-general ARBA prediction. BBS1's role in protein localization is specifically trafficking of membrane cargo to/from the cilium, already captured more precisely by GO:0061512 (protein localization to cilium).
Reason: A more specific term exists that captures the actual function; the generic term adds no value.
Proposed replacements: protein localization to cilium
GO:0034451 centriolar satellite
IEA
GO_REF:0000120 		KEEP AS NON CORE
Summary: BBS proteins associate with centriolar satellites (UniProt subcellular location; PMID:24550735, PMID:18762586). However, the BBSome is dispensable for centriolar satellite function, so this is a staging/regulatory pool rather than a core site of action.
Reason: Centriolar satellite localization is supported but represents a non-core pool; the BBSome's coat/cargo function operates at the ciliary membrane.
GO:0034464 BBSome
IEA
GO_REF:0000120 		ACCEPT
Summary: Duplicate of the core BBSome membership annotation, here by IEA. Correct and core.
GO:0060170 ciliary membrane
IEA
GO_REF:0000044 		ACCEPT
Summary: The BBSome associates with the ciliary membrane where it acts as a cargo coat; directly supported (IDA PMID:19081074) and by UniProt (Cell projection, cilium membrane). Core localization.
GO:1905515 non-motile cilium assembly
IEA
GO_REF:0000120 		ACCEPT
Summary: Duplicate (IEA) of the experimentally and phylogenetically supported non-motile cilium assembly annotation. Correct.
GO:0005515 protein binding
IPI
PMID:17574030
A core complex of BBS proteins cooperates with the GTPase Ra... 		MARK AS OVER ANNOTATED
Summary: Generic protein binding IPI annotations to BBSome subunits and partners (here BBS2, BBS4, BBS7, BBS9, RAB3IP). Per curation guidelines this uninformative term should not be promoted; the meaningful content (BBSome assembly; small GTPase / GEF interaction) is captured by the BBSome part_of annotation and the proposed small GTPase binding term. Flag as over-annotated.
Reason: protein binding is uninformative; the underlying interactions establish complex membership, already captured by GO:0034464.
GO:0005515 protein binding
IPI
PMID:18000879
Novel interaction partners of Bardet-Biedl syndrome proteins... 		MARK AS OVER ANNOTATED
Summary: Interactions reported in an early BBS interaction screen (ALDOB, EEF1A1, PCM1, PARK7). Uninformative protein binding term; several partners are likely non-specific or staging interactions.
Reason: Uninformative MF term; no specific core function is established by these interactions.
GO:0005515 protein binding
IPI
PMID:19081074
A BBSome subunit links ciliogenesis, microtubule stability, ... 		MARK AS OVER ANNOTATED
Summary: BBS1-BBS4 interaction supporting BBSome membership; uninformative generic term.
Reason: Establishes complex membership only; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:19150989
Requirement of Bardet-Biedl syndrome proteins for leptin rec... 		MARK AS OVER ANNOTATED
Summary: BBS1 interaction with the leptin receptor (LEPR). Biologically meaningful (cargo/signaling), but recorded as uninformative protein binding. The functional process is captured by the LEPR surface-trafficking IMP annotation (GO:0043001).
Reason: Uninformative MF term; the relevant signaling-cargo role is recorded elsewhere.
GO:0005515 protein binding
IPI
PMID:20080638
BBS6, BBS10, and BBS12 form a complex with CCT/TRiC family c... 		MARK AS OVER ANNOTATED
Summary: BBS1 interactions with BBS7/BBS9 in the chaperonin-assisted assembly study. Uninformative generic term; supports BBSome assembly.
Reason: Establishes complex assembly only; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:20603001
The conserved Bardet-Biedl syndrome proteins assemble a coat... 		MODIFY
Summary: Interaction with ARL6/BBS3 (Q9H0F7) in the BBSome-coat study. This is the functionally important small GTPase interaction, but annotated only as generic protein binding. A more informative MF term (small GTPase binding) is proposed.
Reason: ARL6/BBS3 is a small monomeric GTPase; the specific MF small GTPase binding is informative and replaces the uninformative generic term.
Proposed replacements: small GTPase binding
GO:0005515 protein binding
IPI
PMID:22139371
Bardet-Biedl syndrome 3 (Bbs3) knockout mouse model reveals ... 		MODIFY
Summary: Interaction with ARL6/BBS3 from the Bbs3 knockout study. Same as above; the informative MF is small GTPase binding.
Reason: ARL6 is a small monomeric GTPase; replace uninformative term with small GTPase binding.
Proposed replacements: small GTPase binding
GO:0005515 protein binding
IPI
PMID:22500027
Intrinsic protein-protein interaction-mediated and chaperoni... 		MARK AS OVER ANNOTATED
Summary: Interactions with BBS subunits (BBS9, BBS7, BBS4, BBS2) in the sequential BBSome-assembly study. Uninformative generic term; supports complex assembly.
Reason: Establishes BBSome assembly; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:25402481
Structural basis for membrane targeting of the BBSome by ARL... 		MODIFY
Summary: Structural study of BBS1 beta-propeller binding ARL6/BBS3-GTP. This is a direct, well-defined small GTPase interaction, annotated here only as generic protein binding. Replace with the specific informative MF.
Reason: Direct structural evidence for BBS1 binding the small GTPase ARL6; small GTPase binding is the informative MF.
Proposed replacements: small GTPase binding
GO:0005515 protein binding
IPI
PMID:25552655
Nephrocystin proteins NPHP5 and Cep290 regulate BBSome integ... 		MARK AS OVER ANNOTATED
Summary: Interaction with NPHP5/IQCB1 (Q15051), a regulator of BBSome integrity and ciliary trafficking. Uninformative generic term.
Reason: Uninformative MF; the regulatory relationship is contextual, not a core BBS1 function.
GO:0005515 protein binding
IPI
PMID:27173435
An organelle-specific protein landscape identifies novel dis... 		MARK AS OVER ANNOTATED
Summary: BBSome-subunit interactions detected in an organelle proteome landscape. Uninformative generic term supporting complex membership.
Reason: High-throughput interactome data establishing complex membership; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:29039417
Protein interaction perturbation profiling at amino-acid res... 		MARK AS OVER ANNOTATED
Summary: BBS9 interaction from amino-acid-resolution interaction perturbation profiling. Uninformative generic term.
Reason: Establishes complex interaction; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:32814053
Interactome Mapping Provides a Network of Neurodegenerative ... 		MARK AS OVER ANNOTATED
Summary: Interactome-mapping hits (DCTN1, PARK7) from a neurodegenerative-disease network study. Uninformative generic term; likely network-screen interactions of uncertain specificity.
Reason: High-throughput interactome data; no specific core function established.
GO:0005515 protein binding
IPI
PMID:33961781
Dual proteome-scale networks reveal cell-specific remodeling... 		MARK AS OVER ANNOTATED
Summary: BBSome-subunit interactions from a proteome-scale interactome. Uninformative generic term supporting complex membership.
Reason: High-throughput data establishing complex membership; covered by GO:0034464.
GO:0005515 protein binding
IPI
PMID:40205054
Multimodal cell maps as a foundation for structural and func... 		MARK AS OVER ANNOTATED
Summary: BBSome-subunit interactions from a multimodal cell-map foundation study. Uninformative generic term supporting complex membership.
Reason: High-throughput data establishing complex membership; covered by GO:0034464.
GO:0005102 signaling receptor binding
IEA
GO_REF:0000120 		KEEP AS NON CORE
Summary: The BBSome recognizes ciliary GPCR cargo (e.g. SSTR3 ciliary targeting signal, LEPR, PC1), so signaling receptor binding is defensible but generic. Retain as non-core; the specific cargo-recognition role is captured by protein localization to cilium.
Reason: Plausible but generic; the informative function is cargo sorting to the cilium.
GO:0005813 centrosome
IEA
GO_REF:0000120 		ACCEPT
Summary: Duplicate (IEA) of the centrosome localization supported by IDA (PMID:18762586) and UniProt.
GO:0005929 cilium
IEA
GO_REF:0000107 		ACCEPT
Summary: BBS1 localizes to the cilium; supported broadly. More specific ciliary membrane is also annotated. Accept as a correct localization.
GO:0031514 motile cilium
IEA
GO_REF:0000107 		MARK AS OVER ANNOTATED
Summary: BBS1/BBSome function is established in non-motile (primary/sensory) cilia. The motile cilium localization is an Ensembl IEA transfer that does not reflect the primary biology of BBS1 in humans.
Reason: BBS1 acts on non-motile primary cilia; motile-cilium localization is an over-propagated electronic inference not supported by the core literature.
GO:0045444 fat cell differentiation
IEA
GO_REF:0000107 		KEEP AS NON CORE
Summary: BBS proteins influence adipogenesis and BBS causes obesity, so a role in fat cell differentiation is plausible as a downstream physiological consequence. Not a core molecular function of BBS1.
Reason: Downstream/physiological role linked to obesity phenotype, not a direct core function.
GO:0051219 phosphoprotein binding
IEA
GO_REF:0000107 		MARK AS OVER ANNOTATED
Summary: An Ensembl IEA transfer with no strong supporting evidence in the BBS1 literature for a defined phosphoprotein-binding activity. Uninformative and weakly supported.
Reason: No experimental support for a specific phosphoprotein-binding molecular function in BBS1; electronic transfer of uncertain validity.
GO:0060271 cilium assembly
IEA
GO_REF:0000107 		ACCEPT
Summary: BBS1 is required for ciliogenesis (IMP PMID:17574030; NAS PMID:19081074). The more specific non-motile cilium assembly is also annotated; cilium assembly is a correct (parent) process term.
GO:0060296 regulation of cilium beat frequency involved in ciliary motility
IEA
GO_REF:0000107 		MARK AS OVER ANNOTATED
Summary: This is a motile-cilia process. BBS1/BBSome act on non-motile primary cilia; this Ensembl IEA term is mis-propagated and contradicts the established primary-cilium biology of BBS1.
Reason: Ciliary beat-frequency regulation applies to motile cilia; BBS1's role is in non-motile primary cilia, so this electronic annotation is inappropriate.
GO:0005829 cytosol
TAS
Reactome:R-HSA-5617815 		ACCEPT
Summary: Reactome places the BBSome (BBSome binds RAB3IP step) in the cytosol prior to ciliary recruitment. Consistent with a cytoplasmic/cytosolic pool of the assembled complex.
GO:0005829 cytosol
TAS
Reactome:R-HSA-5624125 		ACCEPT
Summary: Reactome cytosolic localization for BBSome formation. Consistent with cytoplasmic assembly of the complex.
GO:0005829 cytosol
TAS
Reactome:R-HSA-5624126 		ACCEPT
Summary: Reactome cytosolic localization (ARL6:GTP and BBSome bind ciliary cargo). Accept as a supported localization step.
GO:0005829 cytosol
TAS
Reactome:R-HSA-5624127 		ACCEPT
Summary: Reactome cytosolic localization (cargo targeting to cilium). Accept as a supported step.
GO:0005829 cytosol
TAS
Reactome:R-HSA-5624129 		ACCEPT
Summary: Reactome cytosolic localization (LZTFL1 binds BBSome, preventing premature ciliary traffic). Consistent with cytosolic regulation of BBSome ciliary entry.
GO:0034464 BBSome
IPI
PMID:19081074
A BBSome subunit links ciliogenesis, microtubule stability, ... 		ACCEPT
Summary: Direct evidence (ComplexPortal IPI) for BBS1 as a BBSome subunit. Core annotation.
GO:0060170 ciliary membrane
IDA
PMID:19081074
A BBSome subunit links ciliogenesis, microtubule stability, ... 		ACCEPT
Summary: Direct experimental localization (IDA) of the BBSome to the ciliary membrane. Core localization where the BBSome coat acts.
GO:0060271 cilium assembly
NAS
PMID:19081074
A BBSome subunit links ciliogenesis, microtubule stability, ... 		ACCEPT
Summary: Cilium assembly role; this paper links a BBSome subunit (BBIP10) to ciliogenesis, microtubule stability and acetylation. Correct process for BBS1/BBSome. The more specific non-motile cilium assembly is also annotated.
GO:0005515 protein binding
IPI
PMID:18762586
Recruitment of PCM1 to the centrosome by the cooperative act... 		MARK AS OVER ANNOTATED
Summary: BBS1 interaction with PCM1 (Q9NRI5), a centriolar satellite protein. Uninformative generic term; relates to centrosome/satellite association.
Reason: Uninformative MF; supports the non-core centriolar-satellite/centrosome association.
GO:0005813 centrosome
IDA
PMID:18762586
Recruitment of PCM1 to the centrosome by the cooperative act... 		ACCEPT
Summary: Direct experimental evidence (IDA) for BBS1/BBS4 at the centrosome (DISC1/BBS4/PCM1 study). Supports centrosome localization.
GO:0061512 protein localization to cilium
IMP
PMID:23943788
BBS mutations modify phenotypic expression of CEP290-related... 		ACCEPT
Summary: IMP evidence that BBSome components modulate ciliary localization of cargo (CEP290 module); a core BBS1 process. Experimental annotation by an expert curator who read the full text.
Supporting Evidence:
PMID:23943788
components of the BBSome, a protein complex composed of seven Bardet-Biedl syndrome (BBS) proteins, physically and genetically interact with CEP290 and modulate the expression of disease phenotypes caused by CEP290 mutations.
GO:0005515 protein binding
IPI
PMID:24939912
Bardet-Biedl syndrome proteins 1 and 3 regulate the ciliary ... 		MARK AS OVER ANNOTATED
Summary: BBS1 interaction with polycystin-1/PKD1 (Q8TAM2). Biologically meaningful cargo interaction (BBS1 is the subunit whose loss impairs PC1 ciliary trafficking), but recorded as uninformative generic term; the functional consequence is captured by protein localization to cilium.
Reason: Uninformative MF term; the PC1 cargo-trafficking role is captured by ciliary-localization process annotations.
GO:0034464 BBSome
IDA
PMID:24550735
The centriolar satellite protein AZI1 interacts with BBS4 an... 		ACCEPT
Summary: Direct experimental BBSome membership (AZI1/BBS4 ciliary-trafficking study). Core annotation.
GO:0061629 RNA polymerase II-specific DNA-binding transcription factor binding
IPI
PMID:22302990
Direct role of Bardet-Biedl syndrome proteins in transcripti... 		MARK AS OVER ANNOTATED
Summary: This paper primarily demonstrates a nuclear/transcriptional role and RNF2 (PcG) interaction for BBS7, then proposes a similar role for other BBS proteins. The BBS1-RNF2 IPI extrapolates a transcription-factor-binding MF to BBS1 that is not the established core function of this cytoplasmic ciliary trafficking subunit. Over-annotation.
Reason: The transcriptional/RNF2 role is established chiefly for BBS7; attributing an RNA Pol II TF binding molecular function to BBS1 is a weakly supported extrapolation, not a core BBS1 function.
GO:0005113 patched binding
IPI
PMID:22228099
BBS proteins interact genetically with the IFT pathway to in... 		MARK AS OVER ANNOTATED
Summary: PMID:22228099 is a genetic-interaction / ciliary-accumulation study (loss of BBS genes leads to PTCH1 and SMO accumulation in cilia and a reduced Shh response). It does not demonstrate direct BBS1-PTCH1 molecular binding. The patched binding MF over-interprets a trafficking/regulatory readout. Rather than REMOVE this experimental IPI, it is flagged as an over-annotation because the binding interpretation is not supported by the assay performed.
Reason: The cited experiment shows BBSome-dependent regulation of PTCH1 ciliary levels, not a direct binding activity of BBS1.
GO:0005119 smoothened binding
IPI
PMID:22228099
BBS proteins interact genetically with the IFT pathway to in... 		MARK AS OVER ANNOTATED
Summary: Same source as above; SMO accumulates in cilia upon BBS loss with decreased Shh response. This supports BBSome regulation of SMO ciliary trafficking, not a direct BBS1-SMO binding function.
Reason: Evidence is for regulation of Smoothened ciliary localization via the BBSome, not direct molecular binding by BBS1.
GO:0005515 protein binding
IPI
PMID:16327777
Dissection of epistasis in oligogenic Bardet-Biedl syndrome. 		MARK AS OVER ANNOTATED
Summary: BBS1 interaction with CCDC28B (Q9BUN5), an oligogenic modifier of BBS. Uninformative generic term; relevant to disease modification rather than a defined core molecular function.
Reason: Uninformative MF; CCDC28B is a modifier/interactor, not a core functional partner defining a molecular activity.
GO:0034464 BBSome
IDA
PMID:20080638
BBS6, BBS10, and BBS12 form a complex with CCT/TRiC family c... 		ACCEPT
Summary: Direct experimental BBSome membership from the chaperonin-assisted assembly study. Core annotation.
GO:0043001 Golgi to plasma membrane protein transport
IMP
PMID:19150989
Requirement of Bardet-Biedl syndrome proteins for leptin rec... 		KEEP AS NON CORE
Summary: IMP evidence that BBS proteins are required for leptin receptor signaling, reflecting defective LEPR surface trafficking when BBS function is lost. A real but non-core, cargo-specific role; experimental annotation by a curator who read the full text.
Reason: Reflects a specific cargo (LEPR) trafficking consequence relevant to obesity, not the core ciliary-coat function; retain as a supported non-core process.
GO:0034464 BBSome
IDA
PMID:17574030
A core complex of BBS proteins cooperates with the GTPase Ra... 		ACCEPT
Summary: Original biochemical identification of the BBSome (IDA). Core annotation.
Supporting Evidence:
PMID:17574030
A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis.
GO:0060271 cilium assembly
IMP
PMID:17574030
A core complex of BBS proteins cooperates with the GTPase Ra... 		ACCEPT
Summary: IMP evidence that BBS1/BBSome is required for ciliogenesis. Core process; the more specific non-motile cilium assembly is also annotated.
GO:0045494 photoreceptor cell maintenance
IMP
PMID:17980398
Retinal morphology in patients with BBS1 and BBS10 related B... 		KEEP AS NON CORE
Summary: BBS1 patients show progressive retinal/photoreceptor degeneration (OCT study). This is a tissue-level physiological consequence of ciliary dysfunction in photoreceptors, not a core molecular function. Retain as supported non-core.
Reason: Photoreceptor maintenance is a downstream consequence of BBS1 ciliary function in the connecting cilium, not a direct core activity.
GO:1905515 non-motile cilium assembly
IMP
PMID:17980398
Retinal morphology in patients with BBS1 and BBS10 related B... 		ACCEPT
Summary: Non-motile (primary/photoreceptor) cilium assembly role inferred from BBS1 patient retinal phenotypes. Consistent with the core ciliogenic function of BBS1.

Core Functions

BBS1 is a constitutive core subunit of the BBSome, an octameric coat-like complex that assembles in the cytoplasm and acts at the ciliary membrane to sort transmembrane cargo to and from the primary cilium.

Supporting Evidence:
  • PMID:17574030
    A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis.
  • PMID:20603001
    the BBSome constitutes a coat complex that sorts membrane proteins to primary cilia.

BBS1 mediates membrane targeting of the BBSome by binding the GTP-loaded small GTPase ARL6/BBS3 through its beta-propeller, recruiting the cargo-laden coat to the ciliary membrane.

Molecular Function:
small GTPase binding
Supporting Evidence:
  • PMID:25402481
    Structural basis for membrane targeting of the BBSome by ARL6.
  • PMID:20603001
    The BBSome is the major effector of the Arf-like GTPase Arl6/BBS3, and the BBSome and GTP-bound Arl6 colocalize at ciliary punctae in an interdependent manner.

As part of the BBSome, BBS1 drives localization of membrane proteins (ciliary GPCRs such as SSTR3, Hedgehog component Smoothened, leptin receptor, polycystin-1) to and from the cilium, coupling cargo recognition to intraflagellar transport.

Supporting Evidence:
  • PMID:20603001
    the ciliary targeting signal of somatostatin receptor 3 needs to be directly recognized by the BBSome in order to mediate targeting of membrane proteins to cilia.
  • PMID:24939912
    Only depletion or mutation of BBS1, but not depletion of BBS5 and BBS8, or knockout of BBS4, impairs ciliary trafficking of PC1 in kidney epithelial cells.

BBS1/BBSome is required for assembly and maintenance of non-motile (primary/sensory) cilia, including the photoreceptor connecting cilium; loss of BBS1 disrupts ciliogenesis and ciliary cargo homeostasis.

Supporting Evidence:
  • PMID:17574030
    A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis.

References

GO_REF:0000033
Annotation inferences using phylogenetic trees
GO_REF:0000044
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
GO_REF:0000107
Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
GO_REF:0000117
Electronic Gene Ontology annotations created by ARBA machine learning models
GO_REF:0000120
Combined Automated Annotation using Multiple IEA Methods
PMID:16327777
Dissection of epistasis in oligogenic Bardet-Biedl syndrome.
PMID:17574030
A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis.
PMID:17980398
Retinal morphology in patients with BBS1 and BBS10 related Bardet-Biedl Syndrome evaluated by Fourier-domain optical coherence tomography.
PMID:18000879
Novel interaction partners of Bardet-Biedl syndrome proteins.
PMID:18762586
Recruitment of PCM1 to the centrosome by the cooperative action of DISC1 and BBS4: a candidate for psychiatric illnesses.
PMID:19081074
A BBSome subunit links ciliogenesis, microtubule stability, and acetylation.
PMID:19150989
Requirement of Bardet-Biedl syndrome proteins for leptin receptor signaling.
PMID:20080638
BBS6, BBS10, and BBS12 form a complex with CCT/TRiC family chaperonins and mediate BBSome assembly.
PMID:20603001
The conserved Bardet-Biedl syndrome proteins assemble a coat that traffics membrane proteins to cilia.
PMID:22139371
Bardet-Biedl syndrome 3 (Bbs3) knockout mouse model reveals common BBS-associated phenotypes and Bbs3 unique phenotypes.
PMID:22228099
BBS proteins interact genetically with the IFT pathway to influence SHH-related phenotypes.
PMID:22302990
Direct role of Bardet-Biedl syndrome proteins in transcriptional regulation.
PMID:22500027
Intrinsic protein-protein interaction-mediated and chaperonin-assisted sequential assembly of stable bardet-biedl syndrome protein complex, the BBSome.
PMID:23943788
BBS mutations modify phenotypic expression of CEP290-related ciliopathies.
PMID:24550735
The centriolar satellite protein AZI1 interacts with BBS4 and regulates ciliary trafficking of the BBSome.
PMID:24939912
Bardet-Biedl syndrome proteins 1 and 3 regulate the ciliary trafficking of polycystic kidney disease 1 protein.
PMID:25402481
Structural basis for membrane targeting of the BBSome by ARL6.
PMID:25552655
Nephrocystin proteins NPHP5 and Cep290 regulate BBSome integrity, ciliary trafficking and cargo delivery.
PMID:27173435
An organelle-specific protein landscape identifies novel diseases and molecular mechanisms.
PMID:29039417
Protein interaction perturbation profiling at amino-acid resolution.
PMID:32814053
Interactome Mapping Provides a Network of Neurodegenerative Disease Proteins and Uncovers Widespread Protein Aggregation in Affected Brains.
PMID:33961781
Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.
PMID:40205054
Multimodal cell maps as a foundation for structural and functional genomics.
Reactome:R-HSA-5617815
BBSome binds RAB3IP
Reactome:R-HSA-5624125
Formation of the BBSome
Reactome:R-HSA-5624126
ARL6:GTP and the BBSome bind ciliary cargo
Reactome:R-HSA-5624127
ARL6:GTP and the BBSome target cargo to the primary cilium
Reactome:R-HSA-5624129
LZTFL1 binds the BBSome and prevents its traffic to the cilium

Suggested Questions for Experts

Q: Does the BBS1 beta-propeller directly contribute cargo-recognition specificity for particular ciliary GPCRs, distinct from its ARL6/BBS3 membrane-targeting role?

Suggested experts: Nachury MV, Lorentzen E

Q: Should the Hedgehog-related annotations (patched binding, smoothened binding) be reframed as BBSome-mediated regulation of Smoothened/Patched1 ciliary trafficking rather than direct binding molecular functions?

Suggested experts: Sheffield VC, Nachury MV

Suggested Experiments

Experiment: Use cryo-EM of the reconstituted human BBSome with defined GPCR ciliary-targeting-signal peptides, combined with structure-guided BBS1 beta-propeller mutants tested in ciliary cargo import/export assays in BBS1-null cells.

Hypothesis: BBS1 provides a direct cargo-recognition surface for ciliary GPCRs that is separable from ARL6-mediated membrane targeting.

Type: structural and functional cargo-binding assay

Experiment: Quantify ARL6-GTP binding affinity and ciliary BBSome recruitment for wild-type versus M390R and other propeller variants using purified proteins and live-cell ciliary localization assays.

Hypothesis: Disease alleles of BBS1 (e.g. M390R) impair ARL6/BBS3-GTP binding and thereby reduce BBSome recruitment to the ciliary membrane.

Type: variant biochemistry and ciliary localization assay

Experiment: Assess motile-cilia structure and beat frequency in BBS1-deficient airway/ependymal cells to confirm absence of a primary motile-cilia defect attributable to BBS1.

Hypothesis: The motile cilium and ciliary beat frequency electronic annotations do not reflect a genuine BBS1 role and should be retracted in human.

Type: motile cilia functional assay

πŸ“š Additional Documentation

Notes

(BBS1-notes.md)

BBS1 (Q8NFJ9) research notes

Gene: BBS1 / "BBSome complex member BBS1" / Bardet-Biedl syndrome 1 protein. Human, HGNC:966. 593 aa, chromosome 11.

Summary of function

BBS1 is a core subunit of the BBSome (GO:0034464), an octameric, coat-like protein complex
(BBS1, BBS2, BBS4, BBS5, BBS7, BBS8/TTC8, BBS9, BBIP1/BBIP10). The BBSome is structurally related
to COPI/COPII/clathrin coats and functions as a cargo adaptor that traffics specific transmembrane
proteins (notably ciliary GPCRs and Hedgehog-pathway components) into and out of the primary cilium
by coupling them to intraflagellar transport (IFT).

  • BBSome is a membrane-trafficking coat that sorts membrane proteins to primary cilia
    PMID:20603001.
  • The BBSome is the major effector of the Arf-like GTPase ARL6/BBS3; GTP-bound ARL6 recruits the
    BBSome to the ciliary membrane and the two colocalize at ciliary punctae in an interdependent manner
    PMID:20603001.
  • Cargo recognition: the ciliary targeting signal of somatostatin receptor 3 (SSTR3) is directly
    recognized by the BBSome to mediate ciliary targeting
    PMID:20603001.

BBS1 as the Ξ²-propeller / ARL6-binding subunit

  • Structural work shows BBS1 contains a 7-bladed Ξ²-propeller that binds ARL6/BBS3-GTP, providing the
    membrane-targeting interface of the BBSome PMID:25402481. The IntAct annotation records direct BBS1–ARL6 (Q9H0F7) interaction.
    Disease-causing BBS1 M390R maps to this propeller and weakens ARL6 binding (literature).

BBSome assembly and Rab8/ciliary membrane biogenesis

  • BBS1 was identified as part of the original 7-subunit BBSome core that, together with Rab8 GEF
    (RAB3IP/Rabin8), promotes ciliary membrane biogenesis [PMID:17574030 "A core complex of BBS proteins
    cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis"; UniProt: "INTERACTION WITH
    RAB3IP"]. The BBSome associates with the ciliary membrane and binds RAB3IP/Rabin8, the GEF for Rab8;
    Rab8-GTP then promotes docking/fusion of carrier vesicles at the ciliary base (UniProt FUNCTION).
  • BBSome assembly is chaperonin-assisted: BBS6/BBS10/BBS12 + CCT/TRiC mediate assembly of the BBSome
    [PMID:20080638 "BBS6, BBS10, and BBS12 form a complex with CCT/TRiC family chaperonins and mediate
    BBSome assembly"; BBS1 IDA part_of BBSome from this paper]. Sequential, intrinsic PPI-driven assembly
    with the BBS7–BBS2 and chaperonin intermediates PMID:22500027.

Cargo / signaling roles

  • Hedgehog (SHH): Loss of BBS genes causes accumulation of Smoothened (SMO) and Patched1 (PTCH1) in
    cilia and a decreased Shh response; BBS genes genetically interact with the IFT pathway to modulate
    SHH-related developmental phenotypes PMID:22228099. NOTE: This is a
    genetic interaction / cilia-accumulation study, not a direct binding assay; the "patched binding"
    and "smoothened binding" IPI annotations from this paper are over-interpretations of genetic/trafficking
    data (BBSome regulates SMO/PTCH1 ciliary levels). The IBA propagation of these MF terms is therefore weak.
  • Leptin receptor (LEPR): BBS proteins are required for leptin receptor signaling; BBS1 interacts with
    LEPR and Bbs loss causes leptin resistance (relevant to obesity) [PMID:19150989; IntAct BBS1–Lepr
    (mouse, P48356)]. The "Golgi to plasma membrane protein transport" IMP from this paper reflects defective
    LEPR surface trafficking.
  • Polycystin-1 (PKD1/PC1): BBS1 (and BBS3) regulate ciliary trafficking of PC1; PC1 interacts with a
    subset of BBSome subunits (BBS1/4/5/8) and only BBS1 depletion/mutation impairs PC1 ciliary trafficking
    PMID:24939912. Supports BBS1 as the principal
    cargo-recognition subunit.

Regulation / interactions with NPHP/Cep290 module

  • NPHP5 (IQCB1) and CEP290 regulate BBSome integrity, ciliary trafficking and cargo delivery
    [PMID:25552655; IntAct BBS1–IQCB1 Q15051]. BBSome physically/genetically interacts with CEP290 (via BBS4)
    and modifies CEP290-ciliopathy phenotypes PMID:23943788. BBS1 mutations modify phenotypic expression of
    CEP290-related ciliopathies β€” basis for the IMP "protein localization to cilium" annotation.

Centrosome / centriolar satellites

  • BBS proteins localize at/near the centrosome and centriolar satellites; BBS4 (with DISC1) recruits PCM1
    to the centrosome PMID:18762586. BBS1 IntAct interaction with PCM1 (Q15154) and centrosome IDA derive
    from this/related work. AZI1/CEP131 (centriolar satellite) interacts with BBS4 and regulates BBSome
    ciliary trafficking PMID:24550735. UniProt subcellular location: cilium membrane; cytoplasm;
    centrosome; centriolar satellite. Note the original BBSome paper found the complex is dispensable for
    centriolar satellite function     (UniProt FUNCTION), so centriolar-satellite localization is likely a
    pool/staging location rather than a core functional site.

Transcriptional regulation (PMID:22302990)

  • This paper foregrounds BBS7 (which has a nuclear export signal and interacts with PcG protein RNF2);
    it argues "a similar role for other BBS proteins" in transcription. The BBS1 IPI "RNA polymerase II-specific
    DNA-binding transcription factor binding" to RNF2 (Q99496) is an over-extrapolation from BBS7 data to BBS1
    and is not a core BBS1 function. Keep as non-core / mark over-annotated.

Disease

  • Bardet-Biedl syndrome 1 (BBS1, MIM:209900): pigmentary retinopathy, obesity, polydactyly, hypogenitalism,
    renal malformation, intellectual disability. BBS1 is the most commonly mutated BBS gene; M390R is the
    most common allele [PMID:12118255 founding paper]. Autosomal recessive; some forms show oligogenic/triallelic
    inheritance [PMID:16327777 CCDC28B modifier]. Retinal degeneration / photoreceptor maintenance defects
    PMID:17980398.

Interaction partners (IntAct, from GOA) β€” mostly BBSome subunits + cargo/regulators

  • BBSome subunits: BBS2 (Q9BXC9), BBS4 (Q96RK4), BBS7 (Q8IWZ6), BBS9 (Q3SYG4). These IPI "protein binding"
    annotations simply re-establish complex membership.
  • ARL6/BBS3 (Q9H0F7) β€” small GTPase, membrane-targeting (direct, structural).
  • RAB3IP/Rabin8 (Q96QF0) β€” Rab8 GEF.
  • Cargo/regulators: LEPR (P48356, mouse), PKD1 (Q8TAM2), IQCB1/NPHP5 (Q15051), PCM1 (Q15154).
  • Possibly non-specific / interactome-screen hits: EEF1A1 (P68104), ALDOB (P05062), PARK7/DJ-1 (Q99497),
    DCTN1 (Q14203), CCDC28B (Q9BUN5). Several are from high-throughput interactome maps (PMID:27173435,
    29039417, 32814053, 33961781, 40205054) and the legacy "novel interaction partners" screen (PMID:18000879).

Annotation review judgments (summary)

  • CORE: BBSome (part_of, GO:0034464) β€” strongly supported, multiple IDA. ACCEPT.
  • CORE: protein localization to cilium (GO:0061512) β€” BBSome cargo trafficking. ACCEPT (IMP/IBA).
  • CORE: cilium / non-motile cilium assembly (GO:1905515 / GO:0060271) β€” ACCEPT IMP/IBA.
  • CORE: small GTPase binding β€” not currently annotated as such but is the real MF (ARL6-GTP). The generic
    "protein binding" IPI annotations to ARL6 should ideally be MF small GTPase binding; propose new term.
  • centrosome (GO:0005813), ciliary membrane (GO:0060170), cytosol (GO:0005829), cytoplasm (GO:0005737):
    ACCEPT as supported localizations (cilium membrane + cytoplasm + centrosome per UniProt).
  • centriolar satellite (GO:0034451): KEEP_AS_NON_CORE (staging pool; complex dispensable for satellite fn).
  • axoneme (GO:0005930) IBA: weakly supported β€” BBSome acts at ciliary membrane/base; KEEP_AS_NON_CORE.
  • patched binding / smoothened binding (GO:0005113 / GO:0005119): over-annotated β€” derived from genetic /
    cilia-accumulation data, not direct binding. MARK_AS_OVER_ANNOTATED.
  • RNA Pol II TF binding (GO:0061629): over-annotated, extrapolated from BBS7. MARK_AS_OVER_ANNOTATED.
  • fat cell differentiation (GO:0045444), retina homeostasis (GO:0001895), photoreceptor cell maintenance
    (GO:0045494): downstream/physiological consequences of ciliary dysfunction; KEEP_AS_NON_CORE.
  • regulation of cilium beat frequency involved in ciliary motility (GO:0060296) + motile cilium (GO:0031514):
    BBS1/BBSome act on NON-motile (primary/sensory) cilia; these motile-cilium terms are likely mis-propagated
    Ensembl IEA. MARK_AS_OVER_ANNOTATED / REMOVE candidates (IEA, not curator).
  • Golgi to plasma membrane protein transport (GO:0043001) IMP: from LEPR surface-trafficking; KEEP_AS_NON_CORE.
  • intracellular protein localization (GO:0008104) IEA ARBA: vague generalization of cargo trafficking; MODIFY
    to protein localization to cilium.
  • signaling receptor binding (GO:0005102) IEA: defensible (BBSome binds GPCR cargo) but generic; KEEP_AS_NON_CORE.
  • phosphoprotein binding (GO:0051219) IEA Ensembl: weakly supported; UNDECIDED/over-annotated.
  • protein binding (GO:0005515) IPI Γ—many: uninformative per guidelines; the BBSome-subunit ones support
    complex membership; KEEP_AS_NON_CORE (avoid promoting "protein binding").

πŸ“„ View Raw YAML

 
id: Q8NFJ9
gene_symbol: BBS1
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: BBS1 (Bardet-Biedl syndrome 1 protein) is a core subunit of the BBSome, an octameric,
  coat-like protein complex (BBS1, BBS2, BBS4, BBS5, BBS7, BBS8/TTC8, BBS9 and BBIP1/BBIP10) that is
  structurally related to COPI, COPII and clathrin coats. The BBSome acts as a cargo adaptor that sorts
  specific transmembrane proteins, notably ciliary G-protein-coupled receptors and Hedgehog-pathway
  components such as Smoothened, into and out of the primary cilium by coupling them to intraflagellar
  transport. BBS1 contributes a seven-bladed beta-propeller that provides a principal cargo-recognition
  surface and binds the GTP-loaded Arf-like GTPase ARL6/BBS3, which recruits the BBSome to the ciliary
  membrane. The BBSome cooperates with the Rab8 guanine-nucleotide exchange factor RAB3IP/Rabin8 to
  promote ciliary membrane biogenesis. BBS1 is predominantly found at the ciliary membrane and in the
  cytoplasm, with pools at the centrosome/basal body and centriolar satellites. Loss of BBS1 function
  causes Bardet-Biedl syndrome, an autosomal recessive ciliopathy featuring retinal degeneration,
  obesity, polydactyly, renal malformation, hypogenitalism and intellectual disability; BBS1 is the
  most commonly mutated BBS gene, with M390R the most frequent allele.
alternative_products:
- name: '1'
  id: Q8NFJ9-1
- name: 3 (DPP3-BBS1)
  id: Q8NFJ9-2
  sequence_note: VSP_008854
- name: '2'
  id: Q8NFJ9-3
  sequence_note: VSP_054152, VSP_054153
existing_annotations:
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: part_of
  review:
    summary: BBSome membership is the central, defining feature of BBS1, supported by multiple direct
      experimental annotations (IDA) and phylogeny (IBA). This is a core annotation.
    action: ACCEPT
- term:
    id: GO:0005813
    label: centrosome
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: BBS1 and BBSome subunits localize at/near the centrosome and basal body, consistent with
      UniProt subcellular location and IDA (PMID:18762586). Accept as a supported localization, though
      the centrosome/satellite pool is staging rather than the primary site of cargo-coat action.
    action: ACCEPT
- term:
    id: GO:0061512
    label: protein localization to cilium
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: The core function of the BBSome is to sort membrane proteins to/from the cilium. This is
      well supported (IMP PMID:23943788; IBA) and represents a core BBS1 process.
    action: ACCEPT
- term:
    id: GO:1905515
    label: non-motile cilium assembly
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: BBS1/BBSome act on non-motile (primary/sensory) cilia and are required for ciliogenesis
      (IMP PMID:17574030, PMID:17980398). Non-motile cilium assembly is the appropriate, specific term.
    action: ACCEPT
- term:
    id: GO:0005113
    label: patched binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: This MF is propagated by phylogeny from the experimental IPI annotation (PMID:22228099),
      which is a genetic-interaction / ciliary-accumulation study showing the BBSome regulates SMO and
      PTCH1 ciliary levels, not a direct BBS1-PTCH1 binding assay. The binding claim is over-interpreted;
      the underlying biology (regulation of Hedgehog cargo trafficking) is better captured by ciliary
      trafficking / Hedgehog regulation terms.
    action: MARK_AS_OVER_ANNOTATED
    reason: Direct patched binding by BBS1 is not demonstrated; the source evidence shows regulation of
      PTCH1 ciliary localization via the BBSome, not a molecular binding function.
- term:
    id: GO:0005119
    label: smoothened binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: As with patched binding, this is propagated from PMID:22228099, where loss of BBS genes
      causes SMO accumulation in cilia and reduced Shh response. The BBSome regulates SMO ciliary
      trafficking; direct BBS1-SMO binding is not established. Over-annotation of a trafficking role
      as a binding function.
    action: MARK_AS_OVER_ANNOTATED
    reason: Evidence supports BBSome-dependent regulation of Smoothened ciliary localization, not a
      direct molecular binding activity of BBS1.
- term:
    id: GO:0005930
    label: axoneme
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: The BBSome acts mainly at the ciliary membrane and ciliary base/transition zone and moves
      along the axoneme with IFT; an axonemal pool exists but is not the primary functional site for
      BBS1. Retain as a non-core localization.
    action: KEEP_AS_NON_CORE
    reason: BBSome cargo-coat function is centered on the ciliary membrane; axonemal presence reflects
      IFT-coupled movement rather than a distinct core site of action.
- term:
    id: GO:0001895
    label: retina homeostasis
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: involved_in
  review:
    summary: BBS1 mutations cause retinal degeneration and photoreceptor loss, so this is biologically
      plausible as a downstream physiological consequence of ciliary dysfunction. It is not a core
      molecular/cellular function of BBS1.
    action: KEEP_AS_NON_CORE
    reason: Retina homeostasis is a tissue-level consequence of BBS1 loss (photoreceptor cilium defects),
      not a direct core function.
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: Consistent with UniProt subcellular location (Cytoplasm). A cytoplasmic pool of BBS1/BBSome
      exists prior to ciliary recruitment. Accept, though more specific terms (cytosol, ciliary membrane)
      are also annotated.
    action: ACCEPT
- term:
    id: GO:0008104
    label: intracellular protein localization
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: involved_in
  review:
    summary: This is an over-general ARBA prediction. BBS1's role in protein localization is specifically
      trafficking of membrane cargo to/from the cilium, already captured more precisely by
      GO:0061512 (protein localization to cilium).
    action: MODIFY
    reason: A more specific term exists that captures the actual function; the generic term adds no value.
    proposed_replacement_terms:
    - id: GO:0061512
      label: protein localization to cilium
- term:
    id: GO:0034451
    label: centriolar satellite
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: BBS proteins associate with centriolar satellites (UniProt subcellular location; PMID:24550735,
      PMID:18762586). However, the BBSome is dispensable for centriolar satellite function, so this is a
      staging/regulatory pool rather than a core site of action.
    action: KEEP_AS_NON_CORE
    reason: Centriolar satellite localization is supported but represents a non-core pool; the BBSome's
      coat/cargo function operates at the ciliary membrane.
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: part_of
  review:
    summary: Duplicate of the core BBSome membership annotation, here by IEA. Correct and core.
    action: ACCEPT
- term:
    id: GO:0060170
    label: ciliary membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: The BBSome associates with the ciliary membrane where it acts as a cargo coat; directly
      supported (IDA PMID:19081074) and by UniProt (Cell projection, cilium membrane). Core localization.
    action: ACCEPT
- term:
    id: GO:1905515
    label: non-motile cilium assembly
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: Duplicate (IEA) of the experimentally and phylogenetically supported non-motile cilium
      assembly annotation. Correct.
    action: ACCEPT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:17574030
  qualifier: enables
  review:
    summary: Generic protein binding IPI annotations to BBSome subunits and partners (here BBS2, BBS4,
      BBS7, BBS9, RAB3IP). Per curation guidelines this uninformative term should not be promoted;
      the meaningful content (BBSome assembly; small GTPase / GEF interaction) is captured by the BBSome
      part_of annotation and the proposed small GTPase binding term. Flag as over-annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: protein binding is uninformative; the underlying interactions establish complex membership,
      already captured by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:18000879
  qualifier: enables
  review:
    summary: Interactions reported in an early BBS interaction screen (ALDOB, EEF1A1, PCM1, PARK7).
      Uninformative protein binding term; several partners are likely non-specific or staging interactions.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF term; no specific core function is established by these interactions.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19081074
  qualifier: enables
  review:
    summary: BBS1-BBS4 interaction supporting BBSome membership; uninformative generic term.
    action: MARK_AS_OVER_ANNOTATED
    reason: Establishes complex membership only; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19150989
  qualifier: enables
  review:
    summary: BBS1 interaction with the leptin receptor (LEPR). Biologically meaningful (cargo/signaling),
      but recorded as uninformative protein binding. The functional process is captured by the LEPR
      surface-trafficking IMP annotation (GO:0043001).
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF term; the relevant signaling-cargo role is recorded elsewhere.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20080638
  qualifier: enables
  review:
    summary: BBS1 interactions with BBS7/BBS9 in the chaperonin-assisted assembly study. Uninformative
      generic term; supports BBSome assembly.
    action: MARK_AS_OVER_ANNOTATED
    reason: Establishes complex assembly only; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20603001
  qualifier: enables
  review:
    summary: Interaction with ARL6/BBS3 (Q9H0F7) in the BBSome-coat study. This is the functionally
      important small GTPase interaction, but annotated only as generic protein binding. A more
      informative MF term (small GTPase binding) is proposed.
    action: MODIFY
    reason: ARL6/BBS3 is a small monomeric GTPase; the specific MF small GTPase binding is informative
      and replaces the uninformative generic term.
    proposed_replacement_terms:
    - id: GO:0031267
      label: small GTPase binding
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22139371
  qualifier: enables
  review:
    summary: Interaction with ARL6/BBS3 from the Bbs3 knockout study. Same as above; the informative MF
      is small GTPase binding.
    action: MODIFY
    reason: ARL6 is a small monomeric GTPase; replace uninformative term with small GTPase binding.
    proposed_replacement_terms:
    - id: GO:0031267
      label: small GTPase binding
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22500027
  qualifier: enables
  review:
    summary: Interactions with BBS subunits (BBS9, BBS7, BBS4, BBS2) in the sequential BBSome-assembly
      study. Uninformative generic term; supports complex assembly.
    action: MARK_AS_OVER_ANNOTATED
    reason: Establishes BBSome assembly; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:25402481
  qualifier: enables
  review:
    summary: Structural study of BBS1 beta-propeller binding ARL6/BBS3-GTP. This is a direct, well-defined
      small GTPase interaction, annotated here only as generic protein binding. Replace with the
      specific informative MF.
    action: MODIFY
    reason: Direct structural evidence for BBS1 binding the small GTPase ARL6; small GTPase binding is the
      informative MF.
    proposed_replacement_terms:
    - id: GO:0031267
      label: small GTPase binding
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:25552655
  qualifier: enables
  review:
    summary: Interaction with NPHP5/IQCB1 (Q15051), a regulator of BBSome integrity and ciliary
      trafficking. Uninformative generic term.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; the regulatory relationship is contextual, not a core BBS1 function.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:27173435
  qualifier: enables
  review:
    summary: BBSome-subunit interactions detected in an organelle proteome landscape. Uninformative
      generic term supporting complex membership.
    action: MARK_AS_OVER_ANNOTATED
    reason: High-throughput interactome data establishing complex membership; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:29039417
  qualifier: enables
  review:
    summary: BBS9 interaction from amino-acid-resolution interaction perturbation profiling. Uninformative
      generic term.
    action: MARK_AS_OVER_ANNOTATED
    reason: Establishes complex interaction; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:32814053
  qualifier: enables
  review:
    summary: Interactome-mapping hits (DCTN1, PARK7) from a neurodegenerative-disease network study.
      Uninformative generic term; likely network-screen interactions of uncertain specificity.
    action: MARK_AS_OVER_ANNOTATED
    reason: High-throughput interactome data; no specific core function established.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  qualifier: enables
  review:
    summary: BBSome-subunit interactions from a proteome-scale interactome. Uninformative generic term
      supporting complex membership.
    action: MARK_AS_OVER_ANNOTATED
    reason: High-throughput data establishing complex membership; covered by GO:0034464.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:40205054
  qualifier: enables
  review:
    summary: BBSome-subunit interactions from a multimodal cell-map foundation study. Uninformative
      generic term supporting complex membership.
    action: MARK_AS_OVER_ANNOTATED
    reason: High-throughput data establishing complex membership; covered by GO:0034464.
- term:
    id: GO:0005102
    label: signaling receptor binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: enables
  review:
    summary: The BBSome recognizes ciliary GPCR cargo (e.g. SSTR3 ciliary targeting signal, LEPR, PC1),
      so signaling receptor binding is defensible but generic. Retain as non-core; the specific
      cargo-recognition role is captured by protein localization to cilium.
    action: KEEP_AS_NON_CORE
    reason: Plausible but generic; the informative function is cargo sorting to the cilium.
- term:
    id: GO:0005813
    label: centrosome
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: Duplicate (IEA) of the centrosome localization supported by IDA (PMID:18762586) and UniProt.
    action: ACCEPT
- term:
    id: GO:0005929
    label: cilium
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: located_in
  review:
    summary: BBS1 localizes to the cilium; supported broadly. More specific ciliary membrane is also
      annotated. Accept as a correct localization.
    action: ACCEPT
- term:
    id: GO:0031514
    label: motile cilium
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: located_in
  review:
    summary: BBS1/BBSome function is established in non-motile (primary/sensory) cilia. The motile cilium
      localization is an Ensembl IEA transfer that does not reflect the primary biology of BBS1 in humans.
    action: MARK_AS_OVER_ANNOTATED
    reason: BBS1 acts on non-motile primary cilia; motile-cilium localization is an over-propagated
      electronic inference not supported by the core literature.
- term:
    id: GO:0045444
    label: fat cell differentiation
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: BBS proteins influence adipogenesis and BBS causes obesity, so a role in fat cell
      differentiation is plausible as a downstream physiological consequence. Not a core molecular
      function of BBS1.
    action: KEEP_AS_NON_CORE
    reason: Downstream/physiological role linked to obesity phenotype, not a direct core function.
- term:
    id: GO:0051219
    label: phosphoprotein binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: An Ensembl IEA transfer with no strong supporting evidence in the BBS1 literature for a
      defined phosphoprotein-binding activity. Uninformative and weakly supported.
    action: MARK_AS_OVER_ANNOTATED
    reason: No experimental support for a specific phosphoprotein-binding molecular function in BBS1;
      electronic transfer of uncertain validity.
- term:
    id: GO:0060271
    label: cilium assembly
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: BBS1 is required for ciliogenesis (IMP PMID:17574030; NAS PMID:19081074). The more specific
      non-motile cilium assembly is also annotated; cilium assembly is a correct (parent) process term.
    action: ACCEPT
- term:
    id: GO:0060296
    label: regulation of cilium beat frequency involved in ciliary motility
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: This is a motile-cilia process. BBS1/BBSome act on non-motile primary cilia; this Ensembl
      IEA term is mis-propagated and contradicts the established primary-cilium biology of BBS1.
    action: MARK_AS_OVER_ANNOTATED
    reason: Ciliary beat-frequency regulation applies to motile cilia; BBS1's role is in non-motile
      primary cilia, so this electronic annotation is inappropriate.
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5617815
  qualifier: located_in
  review:
    summary: Reactome places the BBSome (BBSome binds RAB3IP step) in the cytosol prior to ciliary
      recruitment. Consistent with a cytoplasmic/cytosolic pool of the assembled complex.
    action: ACCEPT
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5624125
  qualifier: located_in
  review:
    summary: Reactome cytosolic localization for BBSome formation. Consistent with cytoplasmic assembly
      of the complex.
    action: ACCEPT
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5624126
  qualifier: located_in
  review:
    summary: Reactome cytosolic localization (ARL6:GTP and BBSome bind ciliary cargo). Accept as a
      supported localization step.
    action: ACCEPT
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5624127
  qualifier: located_in
  review:
    summary: Reactome cytosolic localization (cargo targeting to cilium). Accept as a supported step.
    action: ACCEPT
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-5624129
  qualifier: located_in
  review:
    summary: Reactome cytosolic localization (LZTFL1 binds BBSome, preventing premature ciliary traffic).
      Consistent with cytosolic regulation of BBSome ciliary entry.
    action: ACCEPT
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IPI
  original_reference_id: PMID:19081074
  qualifier: part_of
  review:
    summary: Direct evidence (ComplexPortal IPI) for BBS1 as a BBSome subunit. Core annotation.
    action: ACCEPT
- term:
    id: GO:0060170
    label: ciliary membrane
  evidence_type: IDA
  original_reference_id: PMID:19081074
  qualifier: located_in
  review:
    summary: Direct experimental localization (IDA) of the BBSome to the ciliary membrane. Core
      localization where the BBSome coat acts.
    action: ACCEPT
- term:
    id: GO:0060271
    label: cilium assembly
  evidence_type: NAS
  original_reference_id: PMID:19081074
  qualifier: involved_in
  review:
    summary: Cilium assembly role; this paper links a BBSome subunit (BBIP10) to ciliogenesis, microtubule
      stability and acetylation. Correct process for BBS1/BBSome. The more specific non-motile cilium
      assembly is also annotated.
    action: ACCEPT
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:18762586
  qualifier: enables
  review:
    summary: BBS1 interaction with PCM1 (Q9NRI5), a centriolar satellite protein. Uninformative generic
      term; relates to centrosome/satellite association.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; supports the non-core centriolar-satellite/centrosome association.
- term:
    id: GO:0005813
    label: centrosome
  evidence_type: IDA
  original_reference_id: PMID:18762586
  qualifier: located_in
  review:
    summary: Direct experimental evidence (IDA) for BBS1/BBS4 at the centrosome (DISC1/BBS4/PCM1 study).
      Supports centrosome localization.
    action: ACCEPT
- term:
    id: GO:0061512
    label: protein localization to cilium
  evidence_type: IMP
  original_reference_id: PMID:23943788
  qualifier: involved_in
  review:
    summary: IMP evidence that BBSome components modulate ciliary localization of cargo (CEP290 module);
      a core BBS1 process. Experimental annotation by an expert curator who read the full text.
    action: ACCEPT
    supported_by:
    - reference_id: PMID:23943788
      supporting_text: components of the BBSome, a protein complex composed of seven Bardet-Biedl syndrome
        (BBS) proteins, physically and genetically interact with CEP290 and modulate the expression of
        disease phenotypes caused by CEP290 mutations.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24939912
  qualifier: enables
  review:
    summary: BBS1 interaction with polycystin-1/PKD1 (Q8TAM2). Biologically meaningful cargo interaction
      (BBS1 is the subunit whose loss impairs PC1 ciliary trafficking), but recorded as uninformative
      generic term; the functional consequence is captured by protein localization to cilium.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF term; the PC1 cargo-trafficking role is captured by ciliary-localization
      process annotations.
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IDA
  original_reference_id: PMID:24550735
  qualifier: part_of
  review:
    summary: Direct experimental BBSome membership (AZI1/BBS4 ciliary-trafficking study). Core annotation.
    action: ACCEPT
- term:
    id: GO:0061629
    label: RNA polymerase II-specific DNA-binding transcription factor binding
  evidence_type: IPI
  original_reference_id: PMID:22302990
  qualifier: enables
  review:
    summary: This paper primarily demonstrates a nuclear/transcriptional role and RNF2 (PcG) interaction
      for BBS7, then proposes a similar role for other BBS proteins. The BBS1-RNF2 IPI extrapolates a
      transcription-factor-binding MF to BBS1 that is not the established core function of this cytoplasmic
      ciliary trafficking subunit. Over-annotation.
    action: MARK_AS_OVER_ANNOTATED
    reason: The transcriptional/RNF2 role is established chiefly for BBS7; attributing an RNA Pol II TF
      binding molecular function to BBS1 is a weakly supported extrapolation, not a core BBS1 function.
- term:
    id: GO:0005113
    label: patched binding
  evidence_type: IPI
  original_reference_id: PMID:22228099
  qualifier: enables
  review:
    summary: PMID:22228099 is a genetic-interaction / ciliary-accumulation study (loss of BBS genes leads
      to PTCH1 and SMO accumulation in cilia and a reduced Shh response). It does not demonstrate direct
      BBS1-PTCH1 molecular binding. The patched binding MF over-interprets a trafficking/regulatory
      readout. Rather than REMOVE this experimental IPI, it is flagged as an over-annotation because the
      binding interpretation is not supported by the assay performed.
    action: MARK_AS_OVER_ANNOTATED
    reason: The cited experiment shows BBSome-dependent regulation of PTCH1 ciliary levels, not a direct
      binding activity of BBS1.
- term:
    id: GO:0005119
    label: smoothened binding
  evidence_type: IPI
  original_reference_id: PMID:22228099
  qualifier: enables
  review:
    summary: Same source as above; SMO accumulates in cilia upon BBS loss with decreased Shh response.
      This supports BBSome regulation of SMO ciliary trafficking, not a direct BBS1-SMO binding function.
    action: MARK_AS_OVER_ANNOTATED
    reason: Evidence is for regulation of Smoothened ciliary localization via the BBSome, not direct
      molecular binding by BBS1.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16327777
  qualifier: enables
  review:
    summary: BBS1 interaction with CCDC28B (Q9BUN5), an oligogenic modifier of BBS. Uninformative generic
      term; relevant to disease modification rather than a defined core molecular function.
    action: MARK_AS_OVER_ANNOTATED
    reason: Uninformative MF; CCDC28B is a modifier/interactor, not a core functional partner defining a
      molecular activity.
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IDA
  original_reference_id: PMID:20080638
  qualifier: part_of
  review:
    summary: Direct experimental BBSome membership from the chaperonin-assisted assembly study. Core
      annotation.
    action: ACCEPT
- term:
    id: GO:0043001
    label: Golgi to plasma membrane protein transport
  evidence_type: IMP
  original_reference_id: PMID:19150989
  qualifier: acts_upstream_of_or_within
  review:
    summary: IMP evidence that BBS proteins are required for leptin receptor signaling, reflecting
      defective LEPR surface trafficking when BBS function is lost. A real but non-core, cargo-specific
      role; experimental annotation by a curator who read the full text.
    action: KEEP_AS_NON_CORE
    reason: Reflects a specific cargo (LEPR) trafficking consequence relevant to obesity, not the core
      ciliary-coat function; retain as a supported non-core process.
- term:
    id: GO:0034464
    label: BBSome
  evidence_type: IDA
  original_reference_id: PMID:17574030
  qualifier: part_of
  review:
    summary: Original biochemical identification of the BBSome (IDA). Core annotation.
    action: ACCEPT
    supported_by:
    - reference_id: PMID:17574030
      supporting_text: A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary
        membrane biogenesis.
- term:
    id: GO:0060271
    label: cilium assembly
  evidence_type: IMP
  original_reference_id: PMID:17574030
  qualifier: involved_in
  review:
    summary: IMP evidence that BBS1/BBSome is required for ciliogenesis. Core process; the more specific
      non-motile cilium assembly is also annotated.
    action: ACCEPT
- term:
    id: GO:0045494
    label: photoreceptor cell maintenance
  evidence_type: IMP
  original_reference_id: PMID:17980398
  qualifier: involved_in
  review:
    summary: BBS1 patients show progressive retinal/photoreceptor degeneration (OCT study). This is a
      tissue-level physiological consequence of ciliary dysfunction in photoreceptors, not a core
      molecular function. Retain as supported non-core.
    action: KEEP_AS_NON_CORE
    reason: Photoreceptor maintenance is a downstream consequence of BBS1 ciliary function in the
      connecting cilium, not a direct core activity.
- term:
    id: GO:1905515
    label: non-motile cilium assembly
  evidence_type: IMP
  original_reference_id: PMID:17980398
  qualifier: involved_in
  review:
    summary: Non-motile (primary/photoreceptor) cilium assembly role inferred from BBS1 patient retinal
      phenotypes. Consistent with the core ciliogenic function of BBS1.
    action: ACCEPT
core_functions:
- description: BBS1 is a constitutive core subunit of the BBSome, an octameric coat-like complex that
    assembles in the cytoplasm and acts at the ciliary membrane to sort transmembrane cargo to and from
    the primary cilium.
  supported_by:
  - reference_id: PMID:17574030
    supporting_text: A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary
      membrane biogenesis.
  - reference_id: PMID:20603001
    supporting_text: the BBSome constitutes a coat complex that sorts membrane proteins to primary cilia.
- description: BBS1 mediates membrane targeting of the BBSome by binding the GTP-loaded small GTPase
    ARL6/BBS3 through its beta-propeller, recruiting the cargo-laden coat to the ciliary membrane.
  molecular_function:
    id: GO:0031267
    label: small GTPase binding
  supported_by:
  - reference_id: PMID:25402481
    supporting_text: Structural basis for membrane targeting of the BBSome by ARL6.
  - reference_id: PMID:20603001
    supporting_text: The BBSome is the major effector of the Arf-like GTPase Arl6/BBS3, and the BBSome
      and GTP-bound Arl6 colocalize at ciliary punctae in an interdependent manner.
- description: As part of the BBSome, BBS1 drives localization of membrane proteins (ciliary GPCRs such
    as SSTR3, Hedgehog component Smoothened, leptin receptor, polycystin-1) to and from the cilium,
    coupling cargo recognition to intraflagellar transport.
  supported_by:
  - reference_id: PMID:20603001
    supporting_text: the ciliary targeting signal of somatostatin receptor 3 needs to be directly
      recognized by the BBSome in order to mediate targeting of membrane proteins to cilia.
  - reference_id: PMID:24939912
    supporting_text: Only depletion or mutation of BBS1, but not depletion of BBS5 and BBS8, or knockout
      of BBS4, impairs ciliary trafficking of PC1 in kidney epithelial cells.
- description: BBS1/BBSome is required for assembly and maintenance of non-motile (primary/sensory) cilia,
    including the photoreceptor connecting cilium; loss of BBS1 disrupts ciliogenesis and ciliary cargo
    homeostasis.
  supported_by:
  - reference_id: PMID:17574030
    supporting_text: A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary
      membrane biogenesis.
proposed_new_terms: []
suggested_questions:
- question: Does the BBS1 beta-propeller directly contribute cargo-recognition specificity for particular
    ciliary GPCRs, distinct from its ARL6/BBS3 membrane-targeting role?
  experts:
  - Nachury MV
  - Lorentzen E
- question: Should the Hedgehog-related annotations (patched binding, smoothened binding) be reframed
    as BBSome-mediated regulation of Smoothened/Patched1 ciliary trafficking rather than direct binding
    molecular functions?
  experts:
  - Sheffield VC
  - Nachury MV
suggested_experiments:
- hypothesis: BBS1 provides a direct cargo-recognition surface for ciliary GPCRs that is separable from
    ARL6-mediated membrane targeting.
  description: Use cryo-EM of the reconstituted human BBSome with defined GPCR ciliary-targeting-signal
    peptides, combined with structure-guided BBS1 beta-propeller mutants tested in ciliary cargo
    import/export assays in BBS1-null cells.
  experiment_type: structural and functional cargo-binding assay
- hypothesis: Disease alleles of BBS1 (e.g. M390R) impair ARL6/BBS3-GTP binding and thereby reduce
    BBSome recruitment to the ciliary membrane.
  description: Quantify ARL6-GTP binding affinity and ciliary BBSome recruitment for wild-type versus
    M390R and other propeller variants using purified proteins and live-cell ciliary localization assays.
  experiment_type: variant biochemistry and ciliary localization assay
- hypothesis: The motile cilium and ciliary beat frequency electronic annotations do not reflect a
    genuine BBS1 role and should be retracted in human.
  description: Assess motile-cilia structure and beat frequency in BBS1-deficient airway/ependymal cells
    to confirm absence of a primary motile-cilia defect attributable to BBS1.
  experiment_type: motile cilia functional assay
references:
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied by
    UniProt
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:16327777
  title: Dissection of epistasis in oligogenic Bardet-Biedl syndrome.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: PubMed-verified. Identifies CCDC28B as an oligogenic modifier interacting with BBS
      proteins; supports a disease-modifier interaction, not a core molecular function.
- id: PMID:17574030
  title: A core complex of BBS proteins cooperates with the GTPase Rab8 to promote
    ciliary membrane biogenesis.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Foundational paper biochemically defining the BBSome (including BBS1) and its role in
      Rab8-dependent ciliary membrane biogenesis. Abstract-only in cache but the BBSome membership and
      ciliogenesis claims are well established.
- id: PMID:17980398
  title: Retinal morphology in patients with BBS1 and BBS10 related Bardet-Biedl Syndrome
    evaluated by Fourier-domain optical coherence tomography.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Clinical OCT study documenting photoreceptor/retinal degeneration in BBS1 patients;
      supports the non-core photoreceptor-maintenance and non-motile cilium phenotype annotations.
- id: PMID:18000879
  title: Novel interaction partners of Bardet-Biedl syndrome proteins.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Early interaction screen (ALDOB, EEF1A1 etc.); contributes generic protein-binding
      annotations of uncertain specificity.
- id: PMID:18762586
  title: 'Recruitment of PCM1 to the centrosome by the cooperative action of DISC1
    and BBS4: a candidate for psychiatric illnesses.'
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Primarily about BBS4/DISC1/PCM1 at the centrosome; supports BBS1/BBSome centrosome
      localization (IDA) and PCM1 interaction.
- id: PMID:19081074
  title: A BBSome subunit links ciliogenesis, microtubule stability, and acetylation.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: BBIP10/BBSome study; basis for ComplexPortal BBSome membership, ciliary-membrane
      localization and cilium-assembly annotations.
- id: PMID:19150989
  title: Requirement of Bardet-Biedl syndrome proteins for leptin receptor signaling.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Shows BBS proteins are required for leptin receptor signaling/surface trafficking;
      basis for the non-core Golgi-to-plasma-membrane transport annotation relevant to obesity.
- id: PMID:20080638
  title: BBS6, BBS10, and BBS12 form a complex with CCT/TRiC family chaperonins and
    mediate BBSome assembly.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Establishes chaperonin-assisted BBSome assembly; supports BBS1 BBSome membership (IDA).
- id: PMID:20603001
  title: The conserved Bardet-Biedl syndrome proteins assemble a coat that traffics
    membrane proteins to cilia.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Full text available. Demonstrates the BBSome is a coat that sorts membrane proteins to
      cilia, is the major ARL6/BBS3 effector, and directly recognizes GPCR ciliary targeting signals.
      Central evidence for BBS1 core functions.
- id: PMID:22139371
  title: Bardet-Biedl syndrome 3 (Bbs3) knockout mouse model reveals common BBS-associated
    phenotypes and Bbs3 unique phenotypes.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Bbs3/ARL6 knockout study; relevant to the BBS1-ARL6 (small GTPase) interaction
      underlying membrane targeting.
- id: PMID:22228099
  title: BBS proteins interact genetically with the IFT pathway to influence SHH-related
    phenotypes.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: MISCITED
    review_notes: Full text available. Demonstrates BBSome-dependent regulation of SMO/PTCH1 ciliary
      accumulation and reduced Shh response via genetic interaction with IFT. Does NOT show direct BBS1
      binding to Patched or Smoothened; the patched-binding/smoothened-binding IPI annotations derived
      from it over-interpret a trafficking/regulatory readout as a molecular binding function.
- id: PMID:22302990
  title: Direct role of Bardet-Biedl syndrome proteins in transcriptional regulation.
  findings: []
  reference_review:
    relevance: LOW
    correctness: MISCITED
    review_notes: Paper centers on BBS7 nuclear/RNF2 (PcG) function and proposes a similar role for other
      BBS proteins. The BBS1-RNF2 RNA-Pol-II-TF-binding annotation extrapolates BBS7 findings to BBS1 and
      is not a core BBS1 function.
- id: PMID:22500027
  title: Intrinsic protein-protein interaction-mediated and chaperonin-assisted sequential
    assembly of stable bardet-biedl syndrome protein complex, the BBSome.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Defines the sequential, PPI-driven and chaperonin-assisted BBSome assembly pathway;
      supports BBS1 BBSome membership and subunit interactions.
- id: PMID:23943788
  title: BBS mutations modify phenotypic expression of CEP290-related ciliopathies.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Full text available. BBSome physically/genetically interacts with CEP290 and modulates
      ciliary localization/disease expression; basis for the IMP protein-localization-to-cilium annotation.
- id: PMID:24550735
  title: The centriolar satellite protein AZI1 interacts with BBS4 and regulates ciliary
    trafficking of the BBSome.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: Establishes AZI1/CEP131 (centriolar satellite) regulation of BBSome ciliary trafficking;
      supports BBSome membership (IDA) and centriolar-satellite context.
- id: PMID:24939912
  title: Bardet-Biedl syndrome proteins 1 and 3 regulate the ciliary trafficking of
    polycystic kidney disease 1 protein.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Full text available. Shows polycystin-1 interacts with BBS1/4/5/8 and that BBS1
      specifically is required for PC1 ciliary trafficking, highlighting BBS1 as the principal
      cargo-recognition subunit.
- id: PMID:25402481
  title: Structural basis for membrane targeting of the BBSome by ARL6.
  findings: []
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Full text available. Structural basis for BBS1 beta-propeller binding ARL6/BBS3-GTP;
      key evidence for the small GTPase binding molecular function and BBSome membrane targeting.
- id: PMID:25552655
  title: Nephrocystin proteins NPHP5 and Cep290 regulate BBSome integrity, ciliary
    trafficking and cargo delivery.
  findings: []
  reference_review:
    relevance: MEDIUM
    correctness: VERIFIED
    review_notes: NPHP5/CEP290 regulation of BBSome integrity and cargo delivery; supports the regulatory
      interaction context (BBS1-IQCB1).
- id: PMID:27173435
  title: An organelle-specific protein landscape identifies novel diseases and molecular
    mechanisms.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: High-throughput organelle proteome map contributing generic protein-binding annotations
      (BBSome subunits).
- id: PMID:29039417
  title: Protein interaction perturbation profiling at amino-acid resolution.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: High-throughput interaction perturbation profiling; generic protein-binding annotation
      (BBS9).
- id: PMID:32814053
  title: Interactome Mapping Provides a Network of Neurodegenerative Disease Proteins
    and Uncovers Widespread Protein Aggregation in Affected Brains.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Neurodegeneration interactome map; generic protein-binding hits (DCTN1, PARK7) of
      uncertain specificity.
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the human
    interactome.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Proteome-scale interactome (BioPlex-type); generic protein-binding annotations
      establishing BBSome subunit interactions.
- id: PMID:40205054
  title: Multimodal cell maps as a foundation for structural and functional genomics.
  findings: []
  reference_review:
    relevance: LOW
    correctness: VERIFIED
    review_notes: Multimodal cell-map foundation study; generic protein-binding annotations (BBSome
      subunits).
- id: Reactome:R-HSA-5617815
  title: BBSome binds RAB3IP
  findings: []
- id: Reactome:R-HSA-5624125
  title: Formation of the BBSome
  findings: []
- id: Reactome:R-HSA-5624126
  title: ARL6:GTP and the BBSome bind ciliary cargo
  findings: []
- id: Reactome:R-HSA-5624127
  title: ARL6:GTP and the BBSome target cargo to the primary cilium
  findings: []
- id: Reactome:R-HSA-5624129
  title: LZTFL1 binds the BBSome and prevents its traffic to the cilium
  findings: []