Involved in early and late steps in cilia formation. May play a role in early ciliogenesis in the disappearance of centriolar satellites and in the transition of primary ciliar vesicles (PCVs) to capped ciliary vesicles (CCVs). In the ciliary transition zone is part of the tectonic-like complex which is required for tissue-specific ciliogenesis and may regulate ciliary membrane composition. Involved in regulation of the BBSome complex integrity and in ciliary targeting of selected BBSome cargos. Required for the correct localization of ciliary and phototransduction proteins in retinal photoreceptor cells; may play a role in ciliary transport processes (By similarity). Involved in development of the nervous system and kidney (PubMed:16682973). Part of the tectonic-like complex (also named B9 complex). Localizes at the transition zone, a region between the basal body and the ciliary axoneme. At 24 hours post-fertilization (hpf), expressed in the tail in a rostral-to-caudal gradient and more weakly expressed in the cerebellum and retina. At 48 hpf, strongly expressed at the boundary between the developing cerebellum and tectum and in the retina. Morpholino knockdown of the protein causes defects in retinal, cerebellar and otic cavity development and cyst formation in pronephric kidney tubules.