4yd8
Bardet-Biedl Syndrome 9 Protein (aa1-407), Homo sapiens
Structural highlights
DiseasePTHB1_HUMAN Bardet-Biedl syndrome. A chromosomal aberration involving PTHB1 has been found in Wilms tumor. Translocation t(1;7)(q42;p15) with OBSCN. The disease is caused by mutations affecting the gene represented in this entry. FunctionPTHB1_HUMAN 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.[1] [2] Publication Abstract from PubMedThe Bardet-Biedl syndrome protein complex (BBSome) is an octameric complex that transports membrane proteins into the primary cilium signaling organelle in eukaryotes and is implicated in human disease. Here we have analyzed the 99 kDa human BBS9 protein, one of the eight BBSome components. The protein is composed of four structured domains, including a beta-stranded N-terminal domain. The 1.8 A crystal structure of the 46 kDa N-terminal domain reveals a seven-bladed beta-propeller. A structure-based homology search suggests that it functions in protein-protein interactions. We show that the Bardet-Biedl syndrome-causing G141R mutation in BBS9 likely results in misfolding of the beta-propeller. While the C-terminal half of BBS9 dimerizes in solution, the N-terminal domain only does so in the crystal lattice. This C-terminal dimerization interface might be important for the assembly of the BBSome. Structural Characterization of Bardet-Biedl Syndrome 9 Protein (BBS9).,Knockenhauer KE, Schwartz TU J Biol Chem. 2015 Jun 17. pii: jbc.M115.649202. PMID:26085087[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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