Component of the BBSome complex (By similarity). The BBSome complex is thought to function as a coat complex required for sorting of specific membrane proteins to the primary cilia (By similarity). The BBSome complex is required for ciliogenesis but is dispensable for centriolar satellite function (By similarity). Required for BBSome complex ciliary localization but not for the proper complex assembly (By similarity). Required, redundantly with bbs-4, for cilia biogenesis and both the assembly and movement of intraflagellar transport proteins along the ciliary axoneme (PubMed:22922713, PubMed:26150102). Plays a role in the removal of degraded mechanosensory receptors within the cilia (PubMed:26150102). 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 (By similarity). Interacts with bbs-4 (via C-terminus); the interaction is direct (PubMed:26150102). Localizes to basal bodies. Single mutants do not display any obvious defects in ciliogenesis. Double bbs-5 and bbs-4 mutants display a defect in cilia structure and function. This is characterized by increased accumulation and mislocalization of intraflagellar transport proteins and impaired movement of intraflagellar transport proteins along the ciliary axoneme. Double mutants also have defective polycystin-mediated cilia signaling and mislocalized and increased accumulation of mechanosensory receptors pkd-2, osm-9 and odr-10 within cilia. Belongs to the BBS5 family.