Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0034464 BBSome	IBA GO_REF:0000033	ACCEPT	Summary: BBS-8 is a well-established core component of the BBSome complex. This annotation is supported by extensive phylogenetic evidence and direct experimental data showing that BBS-8 associates with other BBSome subunits (BBS-1, BBS-2, BBS-4, BBS-5, BBS-7, BBS-9) to form a functional complex (PMID:22922713). UniProt also confirms BBS-8 is "Part of BBSome complex, that contains at least bbs-1, bbs-2, bbs-4, bbs-5, osm-12, bbs-8/ttc-8 and bbs-9." Reason: Core function. BBSome membership is the most fundamental aspect of BBS-8 function. The BBSome controls IFT assembly and turnaround, and BBS-8 is essential for complex integrity. IBA annotation is strongly supported by experimental evidence from multiple C. elegans studies. Supporting Evidence: PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base file:worm/bbs-8/bbs-8-deep-research-falcon.md model: Edison Scientific Literature
GO:0036064 ciliary basal body	IBA GO_REF:0000033	ACCEPT	Summary: BBS-8 localizes predominantly at the ciliary basal body/base region, from which it facilitates IFT particle assembly. This is well-supported by multiple studies showing BBS-8 enrichment at the ciliary base in C. elegans (PMID:15231740, PMID:22922713, PMID:25335890). Reason: Core localization. The ciliary basal body is the primary site where BBS-8 performs its function in IFT assembly. Multiple experimental papers confirm this localization. Supporting Evidence: PMID:15231740 C. elegans BBS proteins localize predominantly at the base of cilia PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base
GO:0097730 non-motile cilium	IBA GO_REF:0000033	ACCEPT	Summary: C. elegans sensory cilia are non-motile (primary) cilia, and BBS-8 localizes to these structures. This is directly demonstrated by localization studies in amphid and phasmid sensory neurons (PMID:15231740). Reason: Core localization. C. elegans sensory neurons contain non-motile cilia, and BBS-8 function is specific to these ciliated structures. Supporting Evidence: PMID:14520415 all available Caenorhabditis elegans BBS homologues are expressed exclusively in ciliated neurons PMID:15231740 C. elegans BBS proteins localize predominantly at the base of cilia, and like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme
GO:1905515 non-motile cilium assembly	IBA GO_REF:0000033	ACCEPT	Summary: BBS-8 is required for proper cilia assembly through its role in IFT regulation. Loss of BBS-8 results in structural defects in sensory cilia (PMID:15231740). Reason: Core function. BBS-8 regulates IFT assembly, which is essential for building and maintaining cilia. The term appropriately specifies non-motile cilia, which is accurate for C. elegans sensory cilia. Supporting Evidence: PMID:15231740 mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia PMID:22922713 Taken together, we conclude that the BBSome is required for assembling IFT particles at both ciliary base and tip
GO:0005929 cilium	IEA GO_REF:0000044	ACCEPT	Summary: BBS-8 localizes to cilia in C. elegans sensory neurons. This is a broader term than the more specific IBA annotation to "non-motile cilium" but is nonetheless correct. Reason: Correct but general. This IEA annotation is subsumed by the more specific IBA annotation to non-motile cilium (GO:0097730), but retaining it does no harm. Supporting Evidence: PMID:15231740 C. elegans BBS proteins localize predominantly at the base of cilia
GO:0005930 axoneme	IEA GO_REF:0000044	ACCEPT	Summary: BBS-8 undergoes bidirectional movement along the ciliary axoneme as part of IFT particles (PMID:15231740, PMID:22922713). It is transiently present on the axoneme during IFT transport. Reason: Correct localization. BBS-8 moves along the axoneme with IFT particles. While it is enriched at the ciliary base, it does transit through the axoneme during IFT cycles. Supporting Evidence: PMID:15231740 like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then binds to the anterograde IFT particle in a DYF-2- (an orthologue of human WDR19) and BBS-1-dependent manner, and lastly reaches the ciliary tip to regulate proper IFT recycling
GO:0015031 protein transport	IEA GO_REF:0000043	MODIFY	Summary: BBS-8 is involved in protein transport through its role in IFT regulation. The BBSome facilitates transport of membrane proteins and signaling molecules to cilia. However, this term is very general. Reason: Correct but overly general. BBS-8 specifically functions in ciliary protein transport via IFT. A more specific term would better capture the actual function. Proposed replacements: intraciliary transport Supporting Evidence: PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then binds to the anterograde IFT particle in a DYF-2- (an orthologue of human WDR19) and BBS-1-dependent manner, and lastly reaches the ciliary tip to regulate proper IFT recycling
GO:0030030 cell projection organization	IEA GO_REF:0000043	MODIFY	Summary: This is a parent term of cilium organization. BBS-8 is involved in cilium assembly and maintenance, so this annotation is technically correct but very general. Reason: Overly general. The more specific term "cilium assembly" (GO:0060271) or "non-motile cilium assembly" (GO:1905515) would be more appropriate and is already annotated. Proposed replacements: cilium assembly Supporting Evidence: PMID:15231740 mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia
GO:0034464 BBSome	IEA GO_REF:0000002	ACCEPT	Summary: Duplicate of the IBA annotation. InterPro domain IPR028796 (BBS8) correctly maps to BBSome membership. Reason: Correct. This IEA annotation is redundant with the IBA annotation but provides independent computational support for BBSome membership. Supporting Evidence: PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base
GO:1905515 non-motile cilium assembly	IEA GO_REF:0000002	ACCEPT	Summary: Duplicate of the IBA annotation. InterPro mapping correctly identifies involvement in non-motile cilium assembly. Reason: Correct. Redundant with IBA annotation but provides additional computational support. Supporting Evidence: PMID:15231740 mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia
GO:0005929 cilium	NAS PMID:22922713 The BBSome controls IFT assembly and turnaround in cilia.	ACCEPT	Summary: This NAS annotation from ComplexPortal is based on the comprehensive study by Wei et al. demonstrating BBSome function in C. elegans cilia. Reason: Correct localization. The paper directly studies BBS protein localization and function in C. elegans cilia. Supporting Evidence: PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then binds to the anterograde IFT particle
GO:0060271 cilium assembly	NAS PMID:22922713 The BBSome controls IFT assembly and turnaround in cilia.	ACCEPT	Summary: This NAS annotation from ComplexPortal correctly captures that the BBSome (including BBS-8) is required for ciliogenesis. Reason: Core function. The BBSome is essential for IFT-dependent cilium assembly. Supporting Evidence: PMID:22922713 Taken together, we conclude that the BBSome is required for assembling IFT particles at both ciliary base and tip
GO:1903569 positive regulation of protein localization to ciliary membrane	IMP PMID:27930654 Whole-organism developmental expression profiling identifies...	ACCEPT	Summary: This annotation is based on the finding that BBS-8 is required for proper localization of RAB-28 to the periciliary membrane. In bbs-8 mutants, RAB-28(GTP) fails to localize properly to the periciliary membrane. Reason: Well-supported by experimental evidence. The BBSome/BBS-8 facilitates targeting of cargo proteins to ciliary membranes. Supporting Evidence: PMID:27930654 RAB-28 association with the periciliary membrane and IFT is dependent on GTP-binding and the BBSome subunit orthologue, BBS-8
GO:1905798 positive regulation of intraciliary anterograde transport	IMP PMID:27930654 Whole-organism developmental expression profiling identifies...	ACCEPT	Summary: BBS-8 is required for proper anterograde IFT. In bbs-8 mutants, IFT-A and IFT-B dissociate during anterograde transport, indicating BBS-8 positively regulates the integrity of anterograde IFT particles. Reason: Core function. BBS-8/BBSome is essential for maintaining IFT particle integrity during anterograde transport. Loss of BBS-8 results in dissociation of IFT subcomplexes. Supporting Evidence: PMID:22922713 In bbs-7 and bbs-8 null worms, IFT-A and IFT-B dissociate in anterograde IFT transport, resulting in IFT-A moving alone with kinesin-II and IFT-B moving alone with OSM-3
GO:1905801 positive regulation of intraciliary retrograde transport	IMP PMID:27930654 Whole-organism developmental expression profiling identifies...	ACCEPT	Summary: BBS-8 is required for proper retrograde IFT, particularly for the reassembly of IFT-B components into retrograde transport particles at the ciliary tip. Reason: Core function. The BBSome facilitates IFT turnaround at the ciliary tip, enabling proper retrograde transport. Loss of BBS-8 impairs IFT-B recycling. Supporting Evidence: PMID:22922713 Taken together, we conclude that the BBSome is required for assembling IFT particles at both ciliary base and tip PMID:22922713 The absence of the BBSome at the cilia tip leads to the defective recycling of IFT complex
GO:0003674 molecular_function	ND GO_REF:0000015	ACCEPT	Summary: This ND (No biological Data) annotation indicates no specific molecular function has been experimentally determined for BBS-8. While BBS-8 clearly has functions in IFT regulation, its direct molecular activity is not defined. Reason: Appropriate. BBS-8 functions primarily as a structural component of the BBSome complex. No specific enzymatic or binding activity has been characterized that would warrant a more specific MF term. The TPR repeats mediate protein-protein interactions within the complex, but this is captured by the CC annotation to BBSome.
GO:1904107 protein localization to microvillus membrane	IMP PMID:25335890 Ciliopathy proteins establish a bipartite signaling compartm...	MODIFY	Summary: This annotation is based on the finding that BBS-8 is required for proper localization of guanylyl cyclases in AFD neuron finger compartments, which contain microvilli-like structures. However, this annotation may be misleading as the structures in question are part of a specialized ciliary compartment rather than classical microvilli. Reason: The finger compartment of AFD neurons contains microvilli-like protrusions, but these are functionally a specialized ciliary signaling compartment. The term "protein localization to ciliary membrane" would be more accurate. The paper describes BBS-8 facilitating guanylyl cyclase localization to the base of the finger compartment, which is a cilium-related structure. Proposed replacements: protein localization to cilium Supporting Evidence: PMID:25335890 requires BBS-8 and DAF-25 (known as Ankmy2 in mammals) for correct localization of guanylyl cyclases needed for thermosensation
GO:0044292 dendrite terminus	IDA PMID:25335890 Ciliopathy proteins establish a bipartite signaling compartm...	ACCEPT	Summary: BBS-8 was observed at the dendrite terminus in AFD thermosensory neurons, specifically in ring-like structures between the base of the finger compartment and the dendritic membrane. Reason: Correct localization based on direct imaging. BBS-8 localizes to the dendrite terminus where the ciliary base/finger compartment interface is located. Supporting Evidence: PMID:25335890 One compartment, a bona fide cilium, is delineated by proteins associated with Bardet-Biedl syndrome (BBS), Meckel syndrome and nephronophthisis at its base
GO:0097546 ciliary base	IDA PMID:25335890 Ciliopathy proteins establish a bipartite signaling compartm...	ACCEPT	Summary: BBS-8 localizes to the ciliary base, the region where IFT particles are assembled before anterograde transport. This is a key site of BBS-8 function. Reason: Core localization. The ciliary base is the primary site of BBS-8 accumulation and function in IFT assembly. Supporting Evidence: PMID:15231740 C. elegans BBS proteins localize predominantly at the base of cilia
GO:0036064 ciliary basal body	IDA PMID:22922713 The BBSome controls IFT assembly and turnaround in cilia.	ACCEPT	Summary: Direct observation of BBS protein localization at the ciliary basal body in C. elegans. This is consistent with the IBA annotation. Reason: Core localization. Redundant with IBA annotation but provides direct experimental evidence. Supporting Evidence: PMID:22922713 Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base
GO:0097730 non-motile cilium	IDA PMID:15231740 Loss of C. elegans BBS-7 and BBS-8 protein function results ...	ACCEPT	Summary: Direct localization of BBS-8 to non-motile sensory cilia in C. elegans amphid and phasmid neurons. Reason: Core localization. Provides experimental support for the IBA annotation. Supporting Evidence: PMID:15231740 C. elegans BBS proteins localize predominantly at the base of cilia, and like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme
GO:0043005 neuron projection	IDA PMID:14520415 Basal body dysfunction is a likely cause of pleiotropic Bard...	ACCEPT	Summary: BBS-8 was observed in neuron projections in C. elegans. This is a general term that encompasses cilia and dendrites of sensory neurons. Reason: Correct but general. BBS-8 is expressed in ciliated sensory neurons and localizes to their projections (dendrites and cilia). Supporting Evidence: PMID:14520415 all available Caenorhabditis elegans BBS homologues are expressed exclusively in ciliated neurons
GO:1905515 non-motile cilium assembly	IEP PMID:14520415 Basal body dysfunction is a likely cause of pleiotropic Bard...	ACCEPT	Summary: Expression pattern evidence showing BBS-8 expression correlates with cilium assembly in ciliated neurons during development. Reason: Appropriate use of IEP. Expression during ciliogenesis supports involvement in cilium assembly, though this is weaker evidence than the IMP annotations. Supporting Evidence: PMID:14520415 BBS8 localizes specifically to ciliated structures PMID:14520415 contain regulatory elements for RFX, a transcription factor that modulates the expression of genes associated with ciliogenesis and intraflagellar transport
GO:0008355 olfactory learning	IMP PMID:17251413 Caenorhabditis elegans integrates the signals of butanone an...	KEEP AS NON CORE	Summary: bbs-8 mutants show defects in butanone enhancement, a form of olfactory learning. However, this is likely a secondary consequence of ciliary sensory defects rather than a direct function. Reason: This is a downstream phenotype rather than a direct function. BBS genes are required for AWC(ON) neuron function, and defects in this neuron lead to impaired olfactory learning. The primary function of BBS-8 is in cilium/IFT regulation, not learning per se. Supporting Evidence: PMID:17251413 Butanone enhancement also required the functions of Bardet-Biedl syndrome genes in the AWC(ON) neuron but not other genes that control ciliary transport
GO:0060271 cilium assembly	IMP PMID:15231740 Loss of C. elegans BBS-7 and BBS-8 protein function results ...	ACCEPT	Summary: bbs-8 mutants have defective cilia structure, demonstrating BBS-8 is required for normal cilium assembly. Reason: Core function. Direct mutant analysis shows BBS-8 is required for proper cilium formation. Supporting Evidence: PMID:15231740 mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia
GO:0006935 chemotaxis	IMP PMID:15231740 Loss of C. elegans BBS-7 and BBS-8 protein function results ...	KEEP AS NON CORE	Summary: bbs-8 mutants show defective chemotaxis behavior due to impaired sensory cilia function. Reason: This is a downstream phenotype resulting from ciliary sensory defects, not a direct molecular function of BBS-8. Chemotaxis defects are a consequence of impaired cilium function in sensory neurons. Supporting Evidence: PMID:15231740 some of the cardinal and secondary symptoms of BBS, such as obesity, diabetes, cardiomyopathy, and learning defects may result from cilia dysfunction
GO:0042073 intraciliary transport	IMP PMID:15231740 Loss of C. elegans BBS-7 and BBS-8 protein function results ...	ACCEPT	Summary: BBS-8 is required for proper intraciliary transport (IFT). bbs-8 mutants show compromised IFT with IFT-A and IFT-B dissociation during transport. Reason: Core function. This is the primary molecular function of BBS-8 - regulating IFT particle assembly and transport. Direct evidence from multiple studies. Supporting Evidence: PMID:15231740 BBS-7 and BBS-8 are required for the normal localization/motility of the IFT proteins OSM-5/Polaris and CHE-11 PMID:22922713 In bbs-7 and bbs-8 null worms, IFT-A and IFT-B dissociate in anterograde IFT transport, resulting in IFT-A moving alone with kinesin-II and IFT-B moving alone with OSM-3
GO:0060090 molecular adaptor activity	ISS GO_REF:0000024	NEW	Summary: BBS-8 functions as a structural adaptor within the BBSome complex, mediating protein-protein interactions through its TPR (tetratricopeptide repeat) domains. The BBSome acts as a cargo adaptor complex for IFT, and BBS-8 is essential for holding IFT-A and IFT-B subcomplexes together during transport (PMID:22922713). The TPR repeat architecture is a well-characterized protein-protein interaction scaffold. UniProt describes the BBSome as functioning as a "coat complex required for sorting of specific membrane proteins to the primary cilia." Reason: This molecular function annotation is proposed based on the structural role of BBS-8 within the BBSome. The protein contains 7-8 TPR repeats (UniProt), which are canonical protein-protein interaction domains. The BBSome functions as an adaptor/scaffold complex that organizes IFT particles and recruits cargo. BBS-8 is essential for maintaining IFT-A/IFT-B association. The ND annotation for molecular function should be replaced with this more informative term. Supporting Evidence: PMID:22922713 Combined with our findings that the BBSome controls IFT assembly at both ciliary base and tip, it is highly likely that the BBSome functions as a scaffold to organize IFT-A, IFT-B, ciliary membrane receptors, ciliary signaling molecules, and/or other IFT cargos into an entire unit and prepare it for IFT transport. PMID:22922713 The BBSome also shares the common structural features with COPI, COPII, and clathrin coats, and can directly recognize IFT cargos

Core Functions

BBS-8 functions as a core structural component of the BBSome complex, essential for IFT particle assembly at the ciliary base, IFT-A/IFT-B complex integrity during anterograde transport, and IFT turnaround at the ciliary tip. The BBSome including BBS-8 facilitates cargo targeting to ciliary membranes and proper localization of signaling molecules within cilia.

Molecular Function:

molecular adaptor activity

Directly Involved In:

intraciliary transport non-motile cilium assembly protein localization to cilium

Cellular Locations:

ciliary base axoneme

In Complex:

BBSome

Supporting Evidence:

PMID:22922713
Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base

References

GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

GO_REF:0000024

Sequence similarity evidence used in manual assertion

GO_REF:0000015

Use of the ND evidence code for Gene Ontology (GO) terms

GO_REF:0000033

Annotation inferences using phylogenetic trees

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping

PMID:14520415

Basal body dysfunction is a likely cause of pleiotropic Bardet-Biedl syndrome.

First identification of BBS8/TTC8; showed BBS proteins localize to basal bodies and centrosomes

"BBS8 localizes specifically to ciliated structures, such as the connecting cilium of the retina and columnar epithelial cells in the lung"
All C. elegans BBS homologues are expressed exclusively in ciliated neurons

"all available Caenorhabditis elegans BBS homologues are expressed exclusively in ciliated neurons"
BBS8 contains regulatory elements for RFX transcription factor, which modulates ciliogenesis genes

"contain regulatory elements for RFX, a transcription factor that modulates the expression of genes associated with ciliogenesis and intraflagellar transport"

PMID:15231740

Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia defects and compromised intraflagellar transport.

bbs-7 and bbs-8 mutations cause structural and functional defects in cilia

"mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia"
BBS proteins localize predominantly at the base of cilia

"C. elegans BBS proteins localize predominantly at the base of cilia"
BBS proteins move bidirectionally along the ciliary axoneme like IFT proteins

"like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme"
BBS-7 and BBS-8 are required for normal localization/motility of IFT proteins OSM-5 and CHE-11

"BBS-7 and BBS-8 are required for the normal localization/motility of the IFT proteins OSM-5/Polaris and CHE-11"
bbs mutants may exhibit sensory defects leading to behavioral abnormalities

"some of the cardinal and secondary symptoms of BBS, such as obesity, diabetes, cardiomyopathy, and learning defects may result from cilia dysfunction"

PMID:17251413

Caenorhabditis elegans integrates the signals of butanone and food to enhance chemotaxis to butanone.

BBS genes are required in AWC(ON) neuron for butanone enhancement (olfactory learning)

"Butanone enhancement also required the functions of Bardet-Biedl syndrome genes in the AWC(ON) neuron but not other genes that control ciliary transport"
BBS gene function in sensory cilia is important for this learning behavior

"the functions of Bardet-Biedl syndrome genes in sensory cilia may play an important role in this plasticity"

PMID:22922713

The BBSome controls IFT assembly and turnaround in cilia.

The BBSome assembles IFT complexes at the ciliary base

"Further analyses revealed that the BBSome (refs 3, 4), a group of conserved proteins affected in human Bardet-Biedl syndrome(5) (BBS), assembles IFT complexes at the ciliary base"
The BBSome binds to anterograde IFT particles and reaches the ciliary tip

"assembles IFT complexes at the ciliary base, then binds to the anterograde IFT particle in a DYF-2- (an orthologue of human WDR19) and BBS-1-dependent manner, and lastly reaches the ciliary tip to regulate proper IFT recycling"
The BBSome regulates proper IFT recycling/turnaround at the ciliary tip

"lastly reaches the ciliary tip to regulate proper IFT recycling"
In bbs-7 and bbs-8 null worms, IFT-A and IFT-B dissociate during anterograde transport

"In bbs-7 and bbs-8 null worms, IFT-A and IFT-B dissociate in anterograde IFT transport, resulting in IFT-A moving alone with kinesin-II and IFT-B moving alone with OSM-3"
The BBSome is required for assembling IFT particles

"Taken together, we conclude that the BBSome is required for assembling IFT particles at both ciliary base and tip"

PMID:25335890

Ciliopathy proteins establish a bipartite signaling compartment in a C. elegans thermosensory neuron.

BBS-8 localizes at the ciliary base in AFD neurons

"One compartment, a bona fide cilium, is delineated by proteins associated with Bardet-Biedl syndrome (BBS), Meckel syndrome and nephronophthisis at its base"
BBS-8 is required for correct localization of guanylyl cyclases in AFD neurons

"requires BBS-8 and DAF-25 (known as Ankmy2 in mammals) for correct localization of guanylyl cyclases needed for thermosensation"

PMID:27930654

Whole-organism developmental expression profiling identifies RAB-28 as a novel ciliary GTPase associated with the BBSome and intraflagellar transport.

RAB-28 association with the periciliary membrane and IFT is BBS-8 dependent

"RAB-28 association with the periciliary membrane and IFT is dependent on GTP-binding and the BBSome subunit orthologue, BBS-8"
bbs-8 mutants show impaired localization of activated RAB-28 to the periciliary membrane

"BBSome-dependent recruitment of activated RAB-28 to the periciliary membrane"
BBS-8 facilitates cargo targeting to ciliary membranes

"RAB-28 association with the periciliary membrane and IFT is dependent on GTP-binding and the BBSome subunit orthologue, BBS-8"

file:worm/bbs-8/bbs-8-deep-research-falcon.md

Deep research report on bbs-8

Suggested Experiments

Experiment: Structure-function analysis of BBS-8 TPR domains to identify specific regions required for BBSome assembly vs IFT association

Experiment: Crosslinking mass spectrometry to identify direct interaction partners of BBS-8 within the IFT machinery

📚 Additional Documentation

Deep Research Falcon

(bbs-8-deep-research-falcon.md)

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template_file: templates/gene_research_go_focused.md
template_variables:
organism: worm
gene_id: bbs-8
gene_symbol: bbs-8
uniprot_accession: Q23049
protein_description: 'RecName: Full=Tetratricopeptide repeat protein 8 {ECO:0000250|UniProtKB:Q8TAM2};
AltName: Full=Bardet-Biedl syndrome 8 protein homolog {ECO:0000312|WormBase:T25F10.5};'
gene_info: Name=bbs-8 {ECO:0000312|WormBase:T25F10.5}; ORFNames=T25F10.5 {ECO:0000312|WormBase:T25F10.5};
organism_full: Caenorhabditis elegans.
protein_family: Not specified in UniProt
protein_domains: BBS8. (IPR028796); TPR-like_helical_dom_sf. (IPR011990); TPR_rpt.
(IPR019734); TPR_16 (PF13432); TPR_8 (PF13181)
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citation_count: 29

Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

UniProt Accession: Q23049
Protein Description: RecName: Full=Tetratricopeptide repeat protein 8 {ECO:0000250|UniProtKB:Q8TAM2}; AltName: Full=Bardet-Biedl syndrome 8 protein homolog {ECO:0000312|WormBase:T25F10.5};
Gene Information: Name=bbs-8 {ECO:0000312|WormBase:T25F10.5}; ORFNames=T25F10.5 {ECO:0000312|WormBase:T25F10.5};
Organism (full): Caenorhabditis elegans.
Protein Family: Not specified in UniProt
Key Domains: BBS8. (IPR028796); TPR-like_helical_dom_sf. (IPR011990); TPR_rpt. (IPR019734); TPR_16 (PF13432); TPR_8 (PF13181)

MANDATORY VERIFICATION STEPS:

Check if the gene symbol "bbs-8" matches the protein description above
Verify the organism is correct: Caenorhabditis elegans.
Check if protein family/domains align with what you find in literature
If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'bbs-8' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene bbs-8 (gene ID: bbs-8, UniProt: Q23049) in worm.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Output

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

UniProt Accession: Q23049
Protein Description: RecName: Full=Tetratricopeptide repeat protein 8 {ECO:0000250|UniProtKB:Q8TAM2}; AltName: Full=Bardet-Biedl syndrome 8 protein homolog {ECO:0000312|WormBase:T25F10.5};
Gene Information: Name=bbs-8 {ECO:0000312|WormBase:T25F10.5}; ORFNames=T25F10.5 {ECO:0000312|WormBase:T25F10.5};
Organism (full): Caenorhabditis elegans.
Protein Family: Not specified in UniProt
Key Domains: BBS8. (IPR028796); TPR-like_helical_dom_sf. (IPR011990); TPR_rpt. (IPR019734); TPR_16 (PF13432); TPR_8 (PF13181)

MANDATORY VERIFICATION STEPS:

Check if the gene symbol "bbs-8" matches the protein description above
Verify the organism is correct: Caenorhabditis elegans.
Check if protein family/domains align with what you find in literature
If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

Research Target:

Please provide a comprehensive research report on the gene bbs-8 (gene ID: bbs-8, UniProt: Q23049) in worm.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Comprehensive Research Report: bbs-8 (TTC8 homolog) in Caenorhabditis elegans (UniProt Q23049)

Key concepts and definitions

Molecular identity and domain architecture. C. elegans bbs-8 encodes the BBS-8 protein, the worm ortholog of human TTC8, and a core subunit of the conserved BBSome coat-like complex. BBS-8 is a tetratricopeptide repeat (TPR) protein forming an α‑solenoid architecture consistent with multiple TPR repeats (≈12) that scaffold protein–protein interactions, matching its role within the BBSome (TPR_rpt, TPR-like helical domains) (mok2012theidentificationanda pages 36-39, mok2012theidentificationandb pages 39-43).

Cellular localization. In worms, BBS-8/BBSome localizes to ciliated sensory neurons. GFP-tagging places BBSome subunits including BBS-8 at the transition zone/periciliary membrane compartment (PCMC) and along the axoneme, with some studies emphasizing basal body enrichment; overall, the BBSome enters cilia and cycles with IFT (mok2012theidentificationanda pages 36-39, maskova2022searchingforthe pages 10-14, wingfield2018traffickingofciliary pages 4-5).

Primary function and pathway context. The BBSome acts as an adapter for ciliary membrane proteins, especially GPCRs, and couples to the intraflagellar transport (IFT) machinery. In C. elegans, the BBSome is required to coordinate IFT-A and IFT-B subcomplexes and the two anterograde kinesin-2 motors (heterotrimeric kinesin-II and OSM-3). Loss of BBS-8 disrupts this coupling, leading to independent movement of IFT-A and IFT-B at motor-specific velocities, shortened/abnormal cilia, and sensory defects. The BBSome also mediates removal and degradative sorting of activated ciliary receptors, including GPCRs and channels (wingfield2018traffickingofciliary pages 4-5, mok2012theidentificationand pages 39-43, mok2012theidentificationand pages 33-36).

Recent developments and latest research (2023–2024 priority)

Ciliary base dynamics and ordered IFT train assembly. High-resolution single-molecule imaging in C. elegans phasmid neurons (2024–2025) shows distinct delivery routes for IFT subcomplexes versus the BBSome and a stepwise assembly of anterograde trains at the ciliary base/PCMC. BBSome complexes reach the base largely by diffusion and then either bind the periciliary membrane or load late onto assembling trains. In contrast, IFT-B and IFT-A subcomplexes are delivered by directed, vesicle-based transport from the soma; subcomplexes dissociate into a diffusive pool near the base prior to incorporation. Train assembly order: IFT-B loads first (longest pause times), then IFT-A (intermediate), and finally the BBSome (short pauses), indicating a regulated, sequential assembly that positions BBSome as a late-incorporating adapter (bioRxiv Mar 5, 2024; Science Advances Apr 2025) (mitra2024sortingatciliary pages 18-23, mitra2024sortingatciliary pages 23-30, mitra2024sortingatciliary pages 1-3, mitra2024sortingatciliary pages 6-8, mitra2025deliveryofintraflagellar pages 10-12, mitra2025deliveryofintraflagellar pages 1-2, mitra2024sortingatciliary pages 5-6, mitra2024sortingatciliary pages 3-5).

Cilium-independent function in sensory neurons. A 2022 Developmental Cell study in C. elegans discovered a non-ciliary function for the BBSome (including bbs-8) in maintaining the stability of the non-ciliary photoreceptor LITE-1 in ASH neurons via a DLK–MKK–PMK (p38) MAPK pathway, likely by modulating Rab5-dependent endocytosis. LITE-1 protein becomes unstable in adult bbs mutants without changes in mRNA, and loss of dlk-1 or downstream kinases suppresses the photosensation defect and restores LITE-1 protein (Developmental Cell, Jun 2022) (zhang2022aciliaindependentfunction pages 1-3, zhang2022aciliaindependentfunction pages 6-8).

Current applications and real-world implementations
Mechanistic ciliopathy modeling. C. elegans bbs-8 mutants recapitulate core features of Bardet–Biedl syndrome (BBS), enabling in vivo dissection of ciliary GPCR trafficking and IFT coupling. Quantitative motor-velocity readouts in bbs-8 mutants (e.g., ≈0.5 μm/s Kinesin‑II vs ≈1.3 μm/s OSM‑3 when decoupled) serve as robust phenotypic assays for IFT integrity and BBSome function (mok2012theidentificationand pages 39-43, healey2008bbs7regulatescaenorhabditis pages 16-21, healey2008bbs7regulatescaenorhabditisb pages 16-21).
Single-molecule transport assays. New C. elegans imaging frameworks quantify BBSome/IFT delivery routes, pause times, and spatial docking distributions at the PCMC, providing parameters for computational models and for testing candidate modifiers or therapeutics that affect ciliary trafficking (mitra2024sortingatciliary pages 18-23, mitra2024sortingatciliary pages 23-30, mitra2025deliveryofintraflagellar pages 10-12, mitra2025deliveryofintraflagellar pages 1-2).
Expert opinions and analysis from authoritative sources
Reviews emphasize that the BBSome is a conserved adapter that predominantly mediates retrieval/removal of activated ciliary membrane proteins, acting with IFT and small GTPases (e.g., ARL6/BBS3, RAB8) and that in C. elegans the BBSome stabilizes IFT-A/B coupling in the absence of some mammalian coupling factors (IFT25/IFT27/LZTFL1), highlighting organism-specific wiring of the IFT–BBSome interface (Essays in Biochemistry, Oct 2018) (wingfield2018traffickingofciliary pages 4-5).
Synthesis across species indicates C. elegans bbs mutants accumulate ciliary receptors such as ODR-10, OSM-9/OCR-2, and PKD-2; in worms, BBSome promotes removal and lysosome-directed degradative sorting of these cargos, a function conserved in mammals (Scientific Reports, Jul 2015; review synthesis 2022) (wingfield2018traffickingofciliary pages 4-5, maskova2022searchingforthe pages 10-14).
Relevant statistics and data from recent studies
IFT motor decoupling in bbs mutants: Kinesin-II (KAP-1::GFP) ≈0.5 μm s−1 and OSM‑3::GFP ≈1.3 μm s−1 in bbs-1/7/8 mutants; wild-type composite IFT rate ≈0.7 μm s−1 (C. elegans live imaging) (mok2012theidentificationand pages 39-43, healey2008bbs7regulatescaenorhabditis pages 16-21, healey2008bbs7regulatescaenorhabditisb pages 16-21).
Vesicular content and delivery (single-molecule, 2024): ~67% of directed dendritic vesicles contain both IFT-A and IFT-B, ~26.5% only IFT-B, and ~6.5% only IFT-A. BBSome arrival predominantly diffusive; IFT-A/B vesicles slow/pause at defined distances proximal to the base (bioRxiv 2024) (mitra2024sortingatciliary pages 18-23, mitra2024sortingatciliary pages 3-5).
Spatial docking and pause times at the base (2024–2025): mean docking distances and pause times differ—BBSome docks more distal to the base with shorter pauses (~0.4–0.8 s), whereas IFT-B docks closer with longer pauses (>9 s), and IFT-A shows intermediate behavior (bioRxiv 2024; Science Advances 2025) (mitra2024sortingatciliary pages 23-30, mitra2025deliveryofintraflagellar pages 10-12).

Functional evidence in C. elegans specific to bbs-8

(i) Role within the BBSome and IFT. bbs-8 encodes a core BBSome TPR subunit essential for IFT coupling between IFT-A/IFT-B and the two anterograde kinesins. Loss-of-function bbs-8 produces motor decoupling with distinct velocities for Kinesin-II versus OSM-3 and accumulation/mislocalization of IFT components along the cilium, demonstrating BBS-8’s role in stabilizing train composition and motor–cargo associations (mok2012theidentificationand pages 39-43, mok2012theidentificationand pages 33-36, wingfield2018traffickingofciliary pages 4-5).

(ii) Trafficking of ciliary membrane proteins/GPCRs. In worms, BBSome loss leads to accumulation of ciliary receptors (ODR-10 GPCR; OSM-9/OCR-2 TRPV channel; PKD-2 TRPP2) and defects in their removal and degradative sorting; BBS-4 and BBS-5 show redundancy in mediating receptor removal to lysosomes, a BBSome function conserved across species. BBSome is proposed to couple activated cargo to IFT for exit through the transition zone (Scientific Reports 2015; Essays Biochem 2018; modeling/experiments for OCR-2 dynamics 2022) (wingfield2018traffickingofciliary pages 4-5, maskova2022searchingforthe pages 10-14, krugten2022alocalinterplay pages 7-9).

(iii) Phenotypes of bbs-8 loss-of-function. Worm bbs mutants (including bbs-8) exhibit shortened/abnormal sensory cilia, dye-filling (Dyf) defects, chemosensory and osmosensory deficits, and impaired thermosensation; live imaging shows IFT train disorganization and motor decoupling. These phenotypes reflect core defects in ciliary structure and trafficking (wingfield2018traffickingofciliary pages 4-5, mok2012theidentificationanda pages 36-39).

(iv) Cilium-independent functions. Beyond its canonical ciliary role, bbs-8 participates in a cilium-independent pathway regulating the stability of the non-ciliary photoreceptor LITE-1 in ASH neurons through DLK–MKK–PMK (p38) MAPK signaling that modulates Rab5-mediated endocytosis. Genetic suppression of dlk-1 restores LITE-1 protein and photosensitivity in bbs mutants without restoring cilia, demonstrating a separable, non-ciliary function (Developmental Cell 2022) (zhang2022aciliaindependentfunction pages 1-3, zhang2022aciliaindependentfunction pages 6-8).

Regulatory context (transcriptional control)

Expression of bbs-8 is confined to ciliated neurons in C. elegans and falls under the control of the RFX transcription factor DAF-19 via X‑box promoter motifs, consistent with the broader ciliome regulatory program; reporter analyses show bbs-8 promoter activity in ciliated sensory neurons (healey2008bbs7regulatescaenorhabditisa pages 12-16, mok2012theidentificationand pages 33-36).

Alignment with UniProt and domain/family annotations

The literature collectively supports that C. elegans BBS-8 is a TPR-repeat protein in the BBSome (TPR_rpt; TPR-like helical domains), localized to ciliated neurons and functioning in IFT coordination and ciliary membrane protein trafficking. This aligns with UniProt Q23049 annotations and confirms the correct gene/protein identity and organism (mok2012theidentificationanda pages 36-39, mok2012theidentificationandb pages 39-43, wingfield2018traffickingofciliary pages 4-5).

Selected source list with links and dates

Wingfield JL, Lechtreck K-F, Lorentzen E. Trafficking of ciliary membrane proteins by the intraflagellar transport/BBSome machinery. Essays in Biochemistry. Oct 2018. https://doi.org/10.1042/EBC20180030 (wingfield2018traffickingofciliary pages 4-5)
Xu Q et al. BBS4 and BBS5 show functional redundancy in the BBSome to regulate the degradative sorting of ciliary sensory receptors. Scientific Reports. Jul 2015. https://doi.org/10.1038/srep11855 (maskova2022searchingforthe pages 10-14)
Jensen VL et al. Whole-Organism Developmental Expression Profiling Identifies RAB-28 as a Novel Ciliary GTPase Associated with the BBSome and Intraflagellar Transport. PLOS Genetics. Dec 2016. https://doi.org/10.1371/journal.pgen.1006469 (context on BBSome association and ciliary dynamics) (mok2012theidentificationanda pages 36-39)
Zhang X et al. A cilia-independent function of BBSome mediated by DLK-MAPK signaling in C. elegans photosensation. Developmental Cell. Jun 2022. https://doi.org/10.1016/j.devcel.2022.05.005 (zhang2022aciliaindependentfunction pages 1-3, zhang2022aciliaindependentfunction pages 6-8)
van Krugten J et al. A local interplay between diffusion and intraflagellar transport distributes TRPV-channel OCR-2 along C. elegans chemosensory cilia. Communications Biology. Jul 2022. https://doi.org/10.1038/s42003-022-03683-4 (krugten2022alocalinterplay pages 7-9)
Mitra A et al. Sorting at ciliary base and ciliary entry of BBSome, IFT-B and IFT-A. bioRxiv. Mar 5, 2024. https://doi.org/10.1101/2024.03.05.583485 (preprint) (mitra2024sortingatciliary pages 18-23, mitra2024sortingatciliary pages 23-30, mitra2024sortingatciliary pages 1-3, mitra2024sortingatciliary pages 6-8, mitra2024sortingatciliary pages 5-6, mitra2024sortingatciliary pages 3-5)
Mitra A et al. Delivery of intraflagellar transport proteins to the ciliary base and assembly into trains. Science Advances. Apr 2025. https://doi.org/10.1126/sciadv.adr1716 (peer reviewed; complements 2024 preprint) (mitra2025deliveryofintraflagellar pages 10-12, mitra2025deliveryofintraflagellar pages 1-2)

Notes on evidence limits and consistency

Some classical worm data are summarized from theses/reviews that collate primary imaging results; specific numeric motor velocities and motor-decoupling in bbs-8 derive from worm IFT live imaging and are consistent across excerpts (mok2012theidentificationand pages 39-43, healey2008bbs7regulatescaenorhabditis pages 16-21, healey2008bbs7regulatescaenorhabditisb pages 16-21).
The 2024 bioRxiv findings are corroborated by the 2025 peer-reviewed Science Advances paper by the same group in C. elegans, strengthening confidence in the diffusion-versus-directed delivery model and late BBSome incorporation into trains (mitra2024sortingatciliary pages 18-23, mitra2025deliveryofintraflagellar pages 10-12).

Conclusion

C. elegans bbs-8 encodes a TPR-repeat BBSome subunit that localizes to ciliated sensory neurons and is essential for coordinating IFT-A/B and kinesin-2 motors, enabling proper assembly and turnover of IFT trains and regulated trafficking—particularly removal/degradative sorting—of ciliary membrane receptors such as GPCRs and channels. Recent single-molecule studies in worms clarify that BBSomes arrive at the ciliary base predominantly by diffusion and load late onto assembling trains after IFT-B and IFT-A, providing a refined temporal–spatial model of BBSome function. In addition to its canonical ciliary roles, bbs-8 participates in a cilium-independent DLK–MAPK pathway that maintains the stability of a non-ciliary photoreceptor in ASH neurons, revealing broader BBSome functions in neuronal protein homeostasis (wingfield2018traffickingofciliary pages 4-5, mok2012theidentificationand pages 39-43, mitra2024sortingatciliary pages 18-23, mitra2025deliveryofintraflagellar pages 10-12, zhang2022aciliaindependentfunction pages 1-3).

References

(mok2012theidentificationanda pages 36-39): CKF Mok. The identification and characterization of genetic modifiers for bardet-biedl syndrome-associated phenotypes using caenorhabditis elegans. Unknown journal, 2012.
(mok2012theidentificationandb pages 39-43): CKF Mok. The identification and characterization of genetic modifiers for bardet-biedl syndrome-associated phenotypes using caenorhabditis elegans. Unknown journal, 2012.
(maskova2022searchingforthe pages 10-14): K Mašková. Searching for the common function of the bbsome across the evolution and development. Unknown journal, 2022.
(wingfield2018traffickingofciliary pages 4-5): Jenna L. Wingfield, Karl-Ferdinand Lechtreck, and Esben Lorentzen. Trafficking of ciliary membrane proteins by the intraflagellar transport/bbsome machinery. Essays in biochemistry, 62 6:753-763, Oct 2018. URL: https://doi.org/10.1042/ebc20180030, doi:10.1042/ebc20180030. This article has 176 citations and is from a peer-reviewed journal.
(mok2012theidentificationand pages 39-43): CKF Mok. The identification and characterization of genetic modifiers for bardet-biedl syndrome-associated phenotypes using caenorhabditis elegans. Unknown journal, 2012.
(mok2012theidentificationand pages 33-36): CKF Mok. The identification and characterization of genetic modifiers for bardet-biedl syndrome-associated phenotypes using caenorhabditis elegans. Unknown journal, 2012.
(mitra2024sortingatciliary pages 18-23): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(mitra2024sortingatciliary pages 23-30): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(mitra2024sortingatciliary pages 1-3): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(mitra2024sortingatciliary pages 6-8): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(mitra2025deliveryofintraflagellar pages 10-12): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Delivery of intraflagellar transport proteins to the ciliary base and assembly into trains. Science Advances, Apr 2025. URL: https://doi.org/10.1126/sciadv.adr1716, doi:10.1126/sciadv.adr1716. This article has 0 citations and is from a highest quality peer-reviewed journal.
(mitra2025deliveryofintraflagellar pages 1-2): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Delivery of intraflagellar transport proteins to the ciliary base and assembly into trains. Science Advances, Apr 2025. URL: https://doi.org/10.1126/sciadv.adr1716, doi:10.1126/sciadv.adr1716. This article has 0 citations and is from a highest quality peer-reviewed journal.
(mitra2024sortingatciliary pages 5-6): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(mitra2024sortingatciliary pages 3-5): Aniruddha Mitra, Evangelos Gioukakis, Wouter Mul, and Erwin J. G. Peterman. Sorting at ciliary base and ciliary entry of bbsome, ift-b and ift-a. bioRxiv, Mar 2024. URL: https://doi.org/10.1101/2024.03.05.583485, doi:10.1101/2024.03.05.583485. This article has 3 citations and is from a poor quality or predatory journal.
(zhang2022aciliaindependentfunction pages 1-3): Xinxing Zhang, Jinzhi Liu, Tong Pan, Alex Ward, Jianfeng Liu, and X.Z. Shawn Xu. A cilia-independent function of bbsome mediated by dlk-mapk signaling in c. elegans photosensation. Developmental Cell, 57:1545-1557.e4, Jun 2022. URL: https://doi.org/10.1016/j.devcel.2022.05.005, doi:10.1016/j.devcel.2022.05.005. This article has 18 citations and is from a highest quality peer-reviewed journal.
(zhang2022aciliaindependentfunction pages 6-8): Xinxing Zhang, Jinzhi Liu, Tong Pan, Alex Ward, Jianfeng Liu, and X.Z. Shawn Xu. A cilia-independent function of bbsome mediated by dlk-mapk signaling in c. elegans photosensation. Developmental Cell, 57:1545-1557.e4, Jun 2022. URL: https://doi.org/10.1016/j.devcel.2022.05.005, doi:10.1016/j.devcel.2022.05.005. This article has 18 citations and is from a highest quality peer-reviewed journal.
(healey2008bbs7regulatescaenorhabditis pages 16-21): MP Healey. Bbs-7 regulates caenorhabditis elegans body length and fat content through cgmp-dependent signaling. Unknown journal, 2008.
(healey2008bbs7regulatescaenorhabditisb pages 16-21): MP Healey. Bbs-7 regulates caenorhabditis elegans body length and fat content through cgmp-dependent signaling. Unknown journal, 2008.
(krugten2022alocalinterplay pages 7-9): Jaap van Krugten, Noémie Danné, and Erwin J. G. Peterman. A local interplay between diffusion and intraflagellar transport distributes trpv-channel ocr-2 along c. elegans chemosensory cilia. Communications Biology, Jul 2022. URL: https://doi.org/10.1038/s42003-022-03683-4, doi:10.1038/s42003-022-03683-4. This article has 14 citations and is from a peer-reviewed journal.
(healey2008bbs7regulatescaenorhabditisa pages 12-16): MP Healey. Bbs-7 regulates caenorhabditis elegans body length and fat content through cgmp-dependent signaling. Unknown journal, 2008.

Citations

wingfield2018traffickingofciliary pages 4-5
maskova2022searchingforthe pages 10-14
mok2012theidentificationanda pages 36-39
krugten2022alocalinterplay pages 7-9
mok2012theidentificationandb pages 39-43
mok2012theidentificationand pages 39-43
mok2012theidentificationand pages 33-36
mitra2024sortingatciliary pages 18-23
mitra2024sortingatciliary pages 23-30
mitra2024sortingatciliary pages 1-3
mitra2024sortingatciliary pages 6-8
mitra2025deliveryofintraflagellar pages 10-12
mitra2025deliveryofintraflagellar pages 1-2
mitra2024sortingatciliary pages 5-6
mitra2024sortingatciliary pages 3-5
zhang2022aciliaindependentfunction pages 1-3
zhang2022aciliaindependentfunction pages 6-8
https://doi.org/10.1042/EBC20180030
https://doi.org/10.1038/srep11855
https://doi.org/10.1371/journal.pgen.1006469
https://doi.org/10.1016/j.devcel.2022.05.005
https://doi.org/10.1038/s42003-022-03683-4
https://doi.org/10.1101/2024.03.05.583485
https://doi.org/10.1126/sciadv.adr1716
https://doi.org/10.1042/ebc20180030,
https://doi.org/10.1101/2024.03.05.583485,
https://doi.org/10.1126/sciadv.adr1716,
https://doi.org/10.1016/j.devcel.2022.05.005,
https://doi.org/10.1038/s42003-022-03683-4,

📄 View Raw YAML

id: Q23049
gene_symbol: bbs-8
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:6239
  label: Caenorhabditis elegans
description: BBS-8 is the C. elegans ortholog of human TTC8 (tetratricopeptide 
  repeat protein 8), a core component of the BBSome complex. The BBSome is 
  essential for intraflagellar transport (IFT) assembly and regulation. BBS-8 
  contains multiple TPR repeats that mediate protein-protein interactions within
  the complex. BBS-8 is required for proper BBSome assembly at the ciliary base,
  IFT particle integrity during transport, and IFT turnaround at the ciliary 
  tip. Loss of BBS-8 results in dissociation of IFT-A and IFT-B subcomplexes 
  during anterograde transport, leading to cilia structural defects and 
  compromised sensory functions including chemotaxis, thermotaxis, and olfactory
  learning. BBS-8 localizes to the ciliary base, moves along the ciliary axoneme
  with IFT particles, and is enriched in ring-like structures at the base of 
  specialized sensory compartments.
existing_annotations:
  - term:
      id: GO:0034464
      label: BBSome
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: BBS-8 is a well-established core component of the BBSome complex.
        This annotation is supported by extensive phylogenetic evidence and 
        direct experimental data showing that BBS-8 associates with other BBSome
        subunits (BBS-1, BBS-2, BBS-4, BBS-5, BBS-7, BBS-9) to form a functional
        complex (PMID:22922713). UniProt also confirms BBS-8 is "Part of BBSome 
        complex, that contains at least bbs-1, bbs-2, bbs-4, bbs-5, osm-12, 
        bbs-8/ttc-8 and bbs-9."
      action: ACCEPT
      reason: Core function. BBSome membership is the most fundamental aspect of
        BBS-8 function. The BBSome controls IFT assembly and turnaround, and 
        BBS-8 is essential for complex integrity. IBA annotation is strongly 
        supported by experimental evidence from multiple C. elegans studies.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base
        - reference_id: file:worm/bbs-8/bbs-8-deep-research-falcon.md
          supporting_text: 'model: Edison Scientific Literature'
  - term:
      id: GO:0036064
      label: ciliary basal body
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: BBS-8 localizes predominantly at the ciliary basal body/base 
        region, from which it facilitates IFT particle assembly. This is 
        well-supported by multiple studies showing BBS-8 enrichment at the 
        ciliary base in C. elegans (PMID:15231740, PMID:22922713, 
        PMID:25335890).
      action: ACCEPT
      reason: Core localization. The ciliary basal body is the primary site 
        where BBS-8 performs its function in IFT assembly. Multiple experimental
        papers confirm this localization.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: C. elegans BBS proteins localize predominantly at the
            base of cilia
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base
  - term:
      id: GO:0097730
      label: non-motile cilium
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: C. elegans sensory cilia are non-motile (primary) cilia, and 
        BBS-8 localizes to these structures. This is directly demonstrated by 
        localization studies in amphid and phasmid sensory neurons 
        (PMID:15231740).
      action: ACCEPT
      reason: Core localization. C. elegans sensory neurons contain non-motile 
        cilia, and BBS-8 function is specific to these ciliated structures.
      supported_by:
        - reference_id: PMID:14520415
          supporting_text: all available Caenorhabditis elegans BBS homologues 
            are expressed exclusively in ciliated neurons
        - reference_id: PMID:15231740
          supporting_text: C. elegans BBS proteins localize predominantly at the
            base of cilia, and like proteins involved in intraflagellar 
            transport (IFT), a process necessary for cilia biogenesis and 
            maintenance, move bidirectionally along the ciliary axoneme
  - term:
      id: GO:1905515
      label: non-motile cilium assembly
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: BBS-8 is required for proper cilia assembly through its role in 
        IFT regulation. Loss of BBS-8 results in structural defects in sensory 
        cilia (PMID:15231740).
      action: ACCEPT
      reason: Core function. BBS-8 regulates IFT assembly, which is essential 
        for building and maintaining cilia. The term appropriately specifies 
        non-motile cilia, which is accurate for C. elegans sensory cilia.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: mutations in the Caenorhabditis elegans bbs-7 and 
            bbs-8 genes cause structural and functional defects in cilia
        - reference_id: PMID:22922713
          supporting_text: Taken together, we conclude that the BBSome is 
            required for assembling IFT particles at both ciliary base and tip
  - term:
      id: GO:0005929
      label: cilium
    evidence_type: IEA
    original_reference_id: GO_REF:0000044
    review:
      summary: BBS-8 localizes to cilia in C. elegans sensory neurons. This is a
        broader term than the more specific IBA annotation to "non-motile 
        cilium" but is nonetheless correct.
      action: ACCEPT
      reason: Correct but general. This IEA annotation is subsumed by the more 
        specific IBA annotation to non-motile cilium (GO:0097730), but retaining
        it does no harm.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: C. elegans BBS proteins localize predominantly at the
            base of cilia
  - term:
      id: GO:0005930
      label: axoneme
    evidence_type: IEA
    original_reference_id: GO_REF:0000044
    review:
      summary: BBS-8 undergoes bidirectional movement along the ciliary axoneme 
        as part of IFT particles (PMID:15231740, PMID:22922713). It is 
        transiently present on the axoneme during IFT transport.
      action: ACCEPT
      reason: Correct localization. BBS-8 moves along the axoneme with IFT 
        particles. While it is enriched at the ciliary base, it does transit 
        through the axoneme during IFT cycles.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: like proteins involved in intraflagellar transport 
            (IFT), a process necessary for cilia biogenesis and maintenance, 
            move bidirectionally along the ciliary axoneme
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then
            binds to the anterograde IFT particle in a DYF-2- (an orthologue of 
            human WDR19) and BBS-1-dependent manner, and lastly reaches the 
            ciliary tip to regulate proper IFT recycling
  - term:
      id: GO:0015031
      label: protein transport
    evidence_type: IEA
    original_reference_id: GO_REF:0000043
    review:
      summary: BBS-8 is involved in protein transport through its role in IFT 
        regulation. The BBSome facilitates transport of membrane proteins and 
        signaling molecules to cilia. However, this term is very general.
      action: MODIFY
      reason: Correct but overly general. BBS-8 specifically functions in 
        ciliary protein transport via IFT. A more specific term would better 
        capture the actual function.
      proposed_replacement_terms:
        - id: GO:0042073
          label: intraciliary transport
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then
            binds to the anterograde IFT particle in a DYF-2- (an orthologue of 
            human WDR19) and BBS-1-dependent manner, and lastly reaches the 
            ciliary tip to regulate proper IFT recycling
  - term:
      id: GO:0030030
      label: cell projection organization
    evidence_type: IEA
    original_reference_id: GO_REF:0000043
    review:
      summary: This is a parent term of cilium organization. BBS-8 is involved 
        in cilium assembly and maintenance, so this annotation is technically 
        correct but very general.
      action: MODIFY
      reason: Overly general. The more specific term "cilium assembly" 
        (GO:0060271) or "non-motile cilium assembly" (GO:1905515) would be more 
        appropriate and is already annotated.
      proposed_replacement_terms:
        - id: GO:0060271
          label: cilium assembly
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: mutations in the Caenorhabditis elegans bbs-7 and 
            bbs-8 genes cause structural and functional defects in cilia
  - term:
      id: GO:0034464
      label: BBSome
    evidence_type: IEA
    original_reference_id: GO_REF:0000002
    review:
      summary: Duplicate of the IBA annotation. InterPro domain IPR028796 (BBS8)
        correctly maps to BBSome membership.
      action: ACCEPT
      reason: Correct. This IEA annotation is redundant with the IBA annotation 
        but provides independent computational support for BBSome membership.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base
  - term:
      id: GO:1905515
      label: non-motile cilium assembly
    evidence_type: IEA
    original_reference_id: GO_REF:0000002
    review:
      summary: Duplicate of the IBA annotation. InterPro mapping correctly 
        identifies involvement in non-motile cilium assembly.
      action: ACCEPT
      reason: Correct. Redundant with IBA annotation but provides additional 
        computational support.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: mutations in the Caenorhabditis elegans bbs-7 and 
            bbs-8 genes cause structural and functional defects in cilia
  - term:
      id: GO:0005929
      label: cilium
    evidence_type: NAS
    original_reference_id: PMID:22922713
    review:
      summary: This NAS annotation from ComplexPortal is based on the 
        comprehensive study by Wei et al. demonstrating BBSome function in C. 
        elegans cilia.
      action: ACCEPT
      reason: Correct localization. The paper directly studies BBS protein 
        localization and function in C. elegans cilia.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base, then
            binds to the anterograde IFT particle
  - term:
      id: GO:0060271
      label: cilium assembly
    evidence_type: NAS
    original_reference_id: PMID:22922713
    review:
      summary: This NAS annotation from ComplexPortal correctly captures that 
        the BBSome (including BBS-8) is required for ciliogenesis.
      action: ACCEPT
      reason: Core function. The BBSome is essential for IFT-dependent cilium 
        assembly.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Taken together, we conclude that the BBSome is 
            required for assembling IFT particles at both ciliary base and tip
  - term:
      id: GO:1903569
      label: positive regulation of protein localization to ciliary membrane
    evidence_type: IMP
    original_reference_id: PMID:27930654
    review:
      summary: This annotation is based on the finding that BBS-8 is required 
        for proper localization of RAB-28 to the periciliary membrane. In bbs-8 
        mutants, RAB-28(GTP) fails to localize properly to the periciliary 
        membrane.
      action: ACCEPT
      reason: Well-supported by experimental evidence. The BBSome/BBS-8 
        facilitates targeting of cargo proteins to ciliary membranes.
      supported_by:
        - reference_id: PMID:27930654
          supporting_text: RAB-28 association with the periciliary membrane and 
            IFT is dependent on GTP-binding and the BBSome subunit orthologue, 
            BBS-8
  - term:
      id: GO:1905798
      label: positive regulation of intraciliary anterograde transport
    evidence_type: IMP
    original_reference_id: PMID:27930654
    review:
      summary: BBS-8 is required for proper anterograde IFT. In bbs-8 mutants, 
        IFT-A and IFT-B dissociate during anterograde transport, indicating 
        BBS-8 positively regulates the integrity of anterograde IFT particles.
      action: ACCEPT
      reason: Core function. BBS-8/BBSome is essential for maintaining IFT 
        particle integrity during anterograde transport. Loss of BBS-8 results 
        in dissociation of IFT subcomplexes.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: In bbs-7 and bbs-8 null worms, IFT-A and IFT-B 
            dissociate in anterograde IFT transport, resulting in IFT-A moving 
            alone with kinesin-II and IFT-B moving alone with OSM-3
  - term:
      id: GO:1905801
      label: positive regulation of intraciliary retrograde transport
    evidence_type: IMP
    original_reference_id: PMID:27930654
    review:
      summary: BBS-8 is required for proper retrograde IFT, particularly for the
        reassembly of IFT-B components into retrograde transport particles at 
        the ciliary tip.
      action: ACCEPT
      reason: Core function. The BBSome facilitates IFT turnaround at the 
        ciliary tip, enabling proper retrograde transport. Loss of BBS-8 impairs
        IFT-B recycling.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Taken together, we conclude that the BBSome is 
            required for assembling IFT particles at both ciliary base and tip
        - reference_id: PMID:22922713
          supporting_text: The absence of the BBSome at the cilia tip leads to 
            the defective recycling of IFT complex
  - term:
      id: GO:0003674
      label: molecular_function
    evidence_type: ND
    original_reference_id: GO_REF:0000015
    review:
      summary: This ND (No biological Data) annotation indicates no specific 
        molecular function has been experimentally determined for BBS-8. While 
        BBS-8 clearly has functions in IFT regulation, its direct molecular 
        activity is not defined.
      action: ACCEPT
      reason: Appropriate. BBS-8 functions primarily as a structural component 
        of the BBSome complex. No specific enzymatic or binding activity has 
        been characterized that would warrant a more specific MF term. The TPR 
        repeats mediate protein-protein interactions within the complex, but 
        this is captured by the CC annotation to BBSome.
  - term:
      id: GO:1904107
      label: protein localization to microvillus membrane
    evidence_type: IMP
    original_reference_id: PMID:25335890
    review:
      summary: This annotation is based on the finding that BBS-8 is required 
        for proper localization of guanylyl cyclases in AFD neuron finger 
        compartments, which contain microvilli-like structures. However, this 
        annotation may be misleading as the structures in question are part of a
        specialized ciliary compartment rather than classical microvilli.
      action: MODIFY
      reason: The finger compartment of AFD neurons contains microvilli-like 
        protrusions, but these are functionally a specialized ciliary signaling 
        compartment. The term "protein localization to ciliary membrane" would 
        be more accurate. The paper describes BBS-8 facilitating guanylyl 
        cyclase localization to the base of the finger compartment, which is a 
        cilium-related structure.
      proposed_replacement_terms:
        - id: GO:0061512
          label: protein localization to cilium
      additional_reference_ids:
        - PMID:25335890
      supported_by:
        - reference_id: PMID:25335890
          supporting_text: requires BBS-8 and DAF-25 (known as Ankmy2 in 
            mammals) for correct localization of guanylyl cyclases needed for 
            thermosensation
          full_text_unavailable: true
  - term:
      id: GO:0044292
      label: dendrite terminus
    evidence_type: IDA
    original_reference_id: PMID:25335890
    review:
      summary: BBS-8 was observed at the dendrite terminus in AFD thermosensory 
        neurons, specifically in ring-like structures between the base of the 
        finger compartment and the dendritic membrane.
      action: ACCEPT
      reason: Correct localization based on direct imaging. BBS-8 localizes to 
        the dendrite terminus where the ciliary base/finger compartment 
        interface is located.
      supported_by:
        - reference_id: PMID:25335890
          supporting_text: One compartment, a bona fide cilium, is delineated by
            proteins associated with Bardet-Biedl syndrome (BBS), Meckel 
            syndrome and nephronophthisis at its base
          full_text_unavailable: true
  - term:
      id: GO:0097546
      label: ciliary base
    evidence_type: IDA
    original_reference_id: PMID:25335890
    review:
      summary: BBS-8 localizes to the ciliary base, the region where IFT 
        particles are assembled before anterograde transport. This is a key site
        of BBS-8 function.
      action: ACCEPT
      reason: Core localization. The ciliary base is the primary site of BBS-8 
        accumulation and function in IFT assembly.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: C. elegans BBS proteins localize predominantly at the
            base of cilia
  - term:
      id: GO:0036064
      label: ciliary basal body
    evidence_type: IDA
    original_reference_id: PMID:22922713
    review:
      summary: Direct observation of BBS protein localization at the ciliary 
        basal body in C. elegans. This is consistent with the IBA annotation.
      action: ACCEPT
      reason: Core localization. Redundant with IBA annotation but provides 
        direct experimental evidence.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Further analyses revealed that the BBSome (refs 3, 
            4), a group of conserved proteins affected in human Bardet-Biedl 
            syndrome(5) (BBS), assembles IFT complexes at the ciliary base
  - term:
      id: GO:0097730
      label: non-motile cilium
    evidence_type: IDA
    original_reference_id: PMID:15231740
    review:
      summary: Direct localization of BBS-8 to non-motile sensory cilia in C. 
        elegans amphid and phasmid neurons.
      action: ACCEPT
      reason: Core localization. Provides experimental support for the IBA 
        annotation.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: C. elegans BBS proteins localize predominantly at the
            base of cilia, and like proteins involved in intraflagellar 
            transport (IFT), a process necessary for cilia biogenesis and 
            maintenance, move bidirectionally along the ciliary axoneme
  - term:
      id: GO:0043005
      label: neuron projection
    evidence_type: IDA
    original_reference_id: PMID:14520415
    review:
      summary: BBS-8 was observed in neuron projections in C. elegans. This is a
        general term that encompasses cilia and dendrites of sensory neurons.
      action: ACCEPT
      reason: Correct but general. BBS-8 is expressed in ciliated sensory 
        neurons and localizes to their projections (dendrites and cilia).
      supported_by:
        - reference_id: PMID:14520415
          supporting_text: all available Caenorhabditis elegans BBS homologues 
            are expressed exclusively in ciliated neurons
  - term:
      id: GO:1905515
      label: non-motile cilium assembly
    evidence_type: IEP
    original_reference_id: PMID:14520415
    review:
      summary: Expression pattern evidence showing BBS-8 expression correlates 
        with cilium assembly in ciliated neurons during development.
      action: ACCEPT
      reason: Appropriate use of IEP. Expression during ciliogenesis supports 
        involvement in cilium assembly, though this is weaker evidence than the 
        IMP annotations.
      supported_by:
        - reference_id: PMID:14520415
          supporting_text: BBS8 localizes specifically to ciliated structures
        - reference_id: PMID:14520415
          supporting_text: contain regulatory elements for RFX, a transcription 
            factor that modulates the expression of genes associated with 
            ciliogenesis and intraflagellar transport
  - term:
      id: GO:0008355
      label: olfactory learning
    evidence_type: IMP
    original_reference_id: PMID:17251413
    review:
      summary: bbs-8 mutants show defects in butanone enhancement, a form of 
        olfactory learning. However, this is likely a secondary consequence of 
        ciliary sensory defects rather than a direct function.
      action: KEEP_AS_NON_CORE
      reason: This is a downstream phenotype rather than a direct function. BBS 
        genes are required for AWC(ON) neuron function, and defects in this 
        neuron lead to impaired olfactory learning. The primary function of 
        BBS-8 is in cilium/IFT regulation, not learning per se.
      supported_by:
        - reference_id: PMID:17251413
          supporting_text: Butanone enhancement also required the functions of 
            Bardet-Biedl syndrome genes in the AWC(ON) neuron but not other 
            genes that control ciliary transport
  - term:
      id: GO:0060271
      label: cilium assembly
    evidence_type: IMP
    original_reference_id: PMID:15231740
    review:
      summary: bbs-8 mutants have defective cilia structure, demonstrating BBS-8
        is required for normal cilium assembly.
      action: ACCEPT
      reason: Core function. Direct mutant analysis shows BBS-8 is required for 
        proper cilium formation.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: mutations in the Caenorhabditis elegans bbs-7 and 
            bbs-8 genes cause structural and functional defects in cilia
  - term:
      id: GO:0006935
      label: chemotaxis
    evidence_type: IMP
    original_reference_id: PMID:15231740
    review:
      summary: bbs-8 mutants show defective chemotaxis behavior due to impaired 
        sensory cilia function.
      action: KEEP_AS_NON_CORE
      reason: This is a downstream phenotype resulting from ciliary sensory 
        defects, not a direct molecular function of BBS-8. Chemotaxis defects 
        are a consequence of impaired cilium function in sensory neurons.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: some of the cardinal and secondary symptoms of BBS, 
            such as obesity, diabetes, cardiomyopathy, and learning defects may 
            result from cilia dysfunction
  - term:
      id: GO:0042073
      label: intraciliary transport
    evidence_type: IMP
    original_reference_id: PMID:15231740
    review:
      summary: BBS-8 is required for proper intraciliary transport (IFT). bbs-8 
        mutants show compromised IFT with IFT-A and IFT-B dissociation during 
        transport.
      action: ACCEPT
      reason: Core function. This is the primary molecular function of BBS-8 - 
        regulating IFT particle assembly and transport. Direct evidence from 
        multiple studies.
      supported_by:
        - reference_id: PMID:15231740
          supporting_text: BBS-7 and BBS-8 are required for the normal 
            localization/motility of the IFT proteins OSM-5/Polaris and CHE-11
        - reference_id: PMID:22922713
          supporting_text: In bbs-7 and bbs-8 null worms, IFT-A and IFT-B 
            dissociate in anterograde IFT transport, resulting in IFT-A moving 
            alone with kinesin-II and IFT-B moving alone with OSM-3
  - term:
      id: GO:0060090
      label: molecular adaptor activity
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: BBS-8 functions as a structural adaptor within the BBSome 
        complex, mediating protein-protein interactions through its TPR 
        (tetratricopeptide repeat) domains. The BBSome acts as a cargo adaptor 
        complex for IFT, and BBS-8 is essential for holding IFT-A and IFT-B 
        subcomplexes together during transport (PMID:22922713). The TPR repeat 
        architecture is a well-characterized protein-protein interaction 
        scaffold. UniProt describes the BBSome as functioning as a "coat complex
        required for sorting of specific membrane proteins to the primary 
        cilia."
      action: NEW
      reason: This molecular function annotation is proposed based on the 
        structural role of BBS-8 within the BBSome. The protein contains 7-8 TPR
        repeats (UniProt), which are canonical protein-protein interaction 
        domains. The BBSome functions as an adaptor/scaffold complex that 
        organizes IFT particles and recruits cargo. BBS-8 is essential for 
        maintaining IFT-A/IFT-B association. The ND annotation for molecular 
        function should be replaced with this more informative term.
      supported_by:
        - reference_id: PMID:22922713
          supporting_text: Combined with our findings that the BBSome controls 
            IFT assembly at both ciliary base and tip, it is highly likely that 
            the BBSome functions as a scaffold to organize IFT-A, IFT-B, ciliary
            membrane receptors, ciliary signaling molecules, and/or other IFT 
            cargos into an entire unit and prepare it for IFT transport.
        - reference_id: PMID:22922713
          supporting_text: The BBSome also shares the common structural features
            with COPI, COPII, and clathrin coats, and can directly recognize IFT
            cargos
references:
  - id: GO_REF:0000002
    title: Gene Ontology annotation through association of InterPro records with
      GO terms
    findings: []
  - id: GO_REF:0000024
    title: Sequence similarity evidence used in manual assertion
    findings: []
  - id: GO_REF:0000015
    title: Use of the ND evidence code for Gene Ontology (GO) terms
    findings: []
  - id: GO_REF:0000033
    title: Annotation inferences using phylogenetic trees
    findings: []
  - id: GO_REF:0000043
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword 
      mapping
    findings: []
  - id: GO_REF:0000044
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular 
      Location vocabulary mapping
    findings: []
  - id: PMID:14520415
    title: Basal body dysfunction is a likely cause of pleiotropic Bardet-Biedl 
      syndrome.
    findings:
      - statement: First identification of BBS8/TTC8; showed BBS proteins 
          localize to basal bodies and centrosomes
        supporting_text: BBS8 localizes specifically to ciliated structures, 
          such as the connecting cilium of the retina and columnar epithelial 
          cells in the lung
      - statement: All C. elegans BBS homologues are expressed exclusively in 
          ciliated neurons
        supporting_text: all available Caenorhabditis elegans BBS homologues are
          expressed exclusively in ciliated neurons
      - statement: BBS8 contains regulatory elements for RFX transcription 
          factor, which modulates ciliogenesis genes
        supporting_text: contain regulatory elements for RFX, a transcription 
          factor that modulates the expression of genes associated with 
          ciliogenesis and intraflagellar transport
  - id: PMID:15231740
    title: Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia 
      defects and compromised intraflagellar transport.
    findings:
      - statement: bbs-7 and bbs-8 mutations cause structural and functional 
          defects in cilia
        supporting_text: mutations in the Caenorhabditis elegans bbs-7 and bbs-8
          genes cause structural and functional defects in cilia
      - statement: BBS proteins localize predominantly at the base of cilia
        supporting_text: C. elegans BBS proteins localize predominantly at the 
          base of cilia
      - statement: BBS proteins move bidirectionally along the ciliary axoneme 
          like IFT proteins
        supporting_text: like proteins involved in intraflagellar transport 
          (IFT), a process necessary for cilia biogenesis and maintenance, move 
          bidirectionally along the ciliary axoneme
      - statement: BBS-7 and BBS-8 are required for normal localization/motility
          of IFT proteins OSM-5 and CHE-11
        supporting_text: BBS-7 and BBS-8 are required for the normal 
          localization/motility of the IFT proteins OSM-5/Polaris and CHE-11
      - statement: bbs mutants may exhibit sensory defects leading to behavioral
          abnormalities
        supporting_text: some of the cardinal and secondary symptoms of BBS, 
          such as obesity, diabetes, cardiomyopathy, and learning defects may 
          result from cilia dysfunction
  - id: PMID:17251413
    title: Caenorhabditis elegans integrates the signals of butanone and food to
      enhance chemotaxis to butanone.
    findings:
      - statement: BBS genes are required in AWC(ON) neuron for butanone 
          enhancement (olfactory learning)
        supporting_text: Butanone enhancement also required the functions of 
          Bardet-Biedl syndrome genes in the AWC(ON) neuron but not other genes 
          that control ciliary transport
      - statement: BBS gene function in sensory cilia is important for this 
          learning behavior
        supporting_text: the functions of Bardet-Biedl syndrome genes in sensory
          cilia may play an important role in this plasticity
  - id: PMID:22922713
    title: The BBSome controls IFT assembly and turnaround in cilia.
    findings:
      - statement: The BBSome assembles IFT complexes at the ciliary base
        supporting_text: Further analyses revealed that the BBSome (refs 3, 4), 
          a group of conserved proteins affected in human Bardet-Biedl 
          syndrome(5) (BBS), assembles IFT complexes at the ciliary base
      - statement: The BBSome binds to anterograde IFT particles and reaches the
          ciliary tip
        supporting_text: assembles IFT complexes at the ciliary base, then binds
          to the anterograde IFT particle in a DYF-2- (an orthologue of human 
          WDR19) and BBS-1-dependent manner, and lastly reaches the ciliary tip 
          to regulate proper IFT recycling
      - statement: The BBSome regulates proper IFT recycling/turnaround at the 
          ciliary tip
        supporting_text: lastly reaches the ciliary tip to regulate proper IFT 
          recycling
      - statement: In bbs-7 and bbs-8 null worms, IFT-A and IFT-B dissociate 
          during anterograde transport
        supporting_text: In bbs-7 and bbs-8 null worms, IFT-A and IFT-B 
          dissociate in anterograde IFT transport, resulting in IFT-A moving 
          alone with kinesin-II and IFT-B moving alone with OSM-3
      - statement: The BBSome is required for assembling IFT particles
        supporting_text: Taken together, we conclude that the BBSome is required
          for assembling IFT particles at both ciliary base and tip
  - id: PMID:25335890
    title: Ciliopathy proteins establish a bipartite signaling compartment in a 
      C. elegans thermosensory neuron.
    full_text_unavailable: true
    findings:
      - statement: BBS-8 localizes at the ciliary base in AFD neurons
        supporting_text: One compartment, a bona fide cilium, is delineated by 
          proteins associated with Bardet-Biedl syndrome (BBS), Meckel syndrome 
          and nephronophthisis at its base
      - statement: BBS-8 is required for correct localization of guanylyl 
          cyclases in AFD neurons
        supporting_text: requires BBS-8 and DAF-25 (known as Ankmy2 in mammals) 
          for correct localization of guanylyl cyclases needed for 
          thermosensation
  - id: PMID:27930654
    title: Whole-organism developmental expression profiling identifies RAB-28 
      as a novel ciliary GTPase associated with the BBSome and intraflagellar 
      transport.
    findings:
      - statement: RAB-28 association with the periciliary membrane and IFT is 
          BBS-8 dependent
        supporting_text: RAB-28 association with the periciliary membrane and 
          IFT is dependent on GTP-binding and the BBSome subunit orthologue, 
          BBS-8
      - statement: bbs-8 mutants show impaired localization of activated RAB-28 
          to the periciliary membrane
        supporting_text: BBSome-dependent recruitment of activated RAB-28 to the
          periciliary membrane
      - statement: BBS-8 facilitates cargo targeting to ciliary membranes
        supporting_text: RAB-28 association with the periciliary membrane and 
          IFT is dependent on GTP-binding and the BBSome subunit orthologue, 
          BBS-8
  - id: file:worm/bbs-8/bbs-8-deep-research-falcon.md
    title: Deep research report on bbs-8
    findings: []
core_functions:
  - description: BBS-8 functions as a core structural component of the BBSome 
      complex, essential for IFT particle assembly at the ciliary base, 
      IFT-A/IFT-B complex integrity during anterograde transport, and IFT 
      turnaround at the ciliary tip. The BBSome including BBS-8 facilitates 
      cargo targeting to ciliary membranes and proper localization of signaling 
      molecules within cilia.
    molecular_function:
      id: GO:0060090
      label: molecular adaptor activity
    directly_involved_in:
      - id: GO:0042073
        label: intraciliary transport
      - id: GO:1905515
        label: non-motile cilium assembly
      - id: GO:0061512
        label: protein localization to cilium
    locations:
      - id: GO:0097546
        label: ciliary base
      - id: GO:0005930
        label: axoneme
    in_complex:
      id: GO:0034464
      label: BBSome
    supported_by:
      - reference_id: PMID:22922713
        supporting_text: Further analyses revealed that the BBSome (refs 3, 4), 
          a group of conserved proteins affected in human Bardet-Biedl 
          syndrome(5) (BBS), assembles IFT complexes at the ciliary base
proposed_new_terms: []
suggested_questions:
  - question: What is the precise molecular mechanism by which BBS-8 contributes
      to IFT-A/IFT-B complex stability during anterograde transport?
  - question: Does BBS-8 have any direct cargo binding activity, or does it only
      function as a structural component of the BBSome?
  - question: Are there specific TPR repeat domains in BBS-8 that mediate 
      interactions with different BBSome subunits or IFT components?
suggested_experiments:
  - description: Structure-function analysis of BBS-8 TPR domains to identify 
      specific regions required for BBSome assembly vs IFT association
  - description: Crosslinking mass spectrometry to identify direct interaction 
      partners of BBS-8 within the IFT machinery
tags:
  - caeel-ciliopathy

bbs-8

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Deep Research Falcon

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Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

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Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

Target Gene/Protein Identity (from UniProt):

MANDATORY VERIFICATION STEPS:

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

Research Target:

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