May be required for the dynein-mediated transport of pericentriolar proteins to the centrosome. Required for microtubule anchoring at the centrosome but not for microtubule nucleation. 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 (By similarity). Part of BBSome complex, that contains BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBIP10 (By similarity). Interacts with PCM1 and DCTN1 (By similarity). Interacts with CCDC28B (By similarity). Interacts with ALDOB and C2CD3 (By similarity). Interacts with PKD1 (By similarity). Interacts with CEP290 (By similarity). Interacts with DLEC1 (By similarity). Localizes to the pericentriolar material. Centrosomal localization requires dynein (By similarity). Localizes to the connecting cilium of photoreceptor cells (By similarity). Belongs to the BBS4 family.