4yd8

Structural highlights

Disease

[PTHB1_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.

Function

[PTHB1_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]}

References

1. ↑ Nachury MV, Loktev AV, Zhang Q, Westlake CJ, Peranen J, Merdes A, Slusarski DC, Scheller RH, Bazan JF, Sheffield VC, Jackson PK. A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesis. Cell. 2007 Jun 15;129(6):1201-13. PMID:17574030 doi:http://dx.doi.org/10.1016/j.cell.2007.03.053
2. ↑ Seo S, Zhang Q, Bugge K, Breslow DK, Searby CC, Nachury MV, Sheffield VC. A novel protein LZTFL1 regulates ciliary trafficking of the BBSome and Smoothened. PLoS Genet. 2011 Nov;7(11):e1002358. doi: 10.1371/journal.pgen.1002358. Epub 2011, Nov 3. PMID:22072986 doi:http://dx.doi.org/10.1371/journal.pgen.1002358