BBS9
Function
The BBSome complex is thought to function as a coat complex required for sorting of specific membrane proteins to the primary cilia. The BBSome complex is required for ciliogenesis but is dispensable for centriolar satellite function. This ciliogenic function is mediated in part by the Rab8 GDP/GTP exchange factor, which localizes to the basal body and contacts the BBSome. Rab8(GTP) enters the primary cilium and promotes extension of the ciliary membrane. Firstly the BBSome associates with the ciliary membrane and binds to RAB3IP/Rabin8, the guanosyl exchange factor (GEF) for Rab8 and then the Rab8-GTP localizes to the cilium and promotes docking and fusion of carrier vesicles to the base of the ciliary membrane. Required for proper BBSome complex assembly and its ciliary localization.
Involvement in disease
A chromosomal aberration involving PTHB1 has been found in Wilms tumor. Translocation t(1;7)(q42;p15) with OBSCN.
Bardet-Biedl syndrome 9
BBS9
A syndrome characterized by usually severe pigmentary retinopathy, early-onset obesity, polydactyly, hypogenitalism, renal malformation and intellectual disability. Secondary features include diabetes mellitus, hypertension and congenital heart disease. Bardet-Biedl syndrome inheritance is autosomal recessive, but three mutated alleles (two at one locus, and a third at a second locus) may be required for clinical manifestation of some forms of the disease.
None
The disease is caused by variants affecting the gene represented in this entry.
Tissue Specificity
Widely expressed. Expressed in adult heart, skeletal muscle, lung, liver, kidney, placenta and brain, and in fetal kidney, lung, liver and brain.
Cellular localization
- Cytoplasm
- Cytoskeleton
- Microtubule organizing center
- Centrosome
- Cell projection
- Cilium membrane
- Cytoplasm
- Cytoplasm
- Cytoskeleton
- Microtubule organizing center
- Centrosome
- Centriolar satellite
Alternative names
PTHB1, BBS9, Protein PTHB1, Bardet-Biedl syndrome 9 protein, Parathyroid hormone-responsive B1 gene protein