Cilium- and flagellum-specific protein that plays a role in axonemal structure organization and motility. Plays a role in outer and inner axonemal dynein arm assembly. Localizes predominantly in the cytoplasm and weakly in cilia. Transported within cilia in an intraflagellar transport (IFT)-dependent manner. Accumulates at the ciliary tips during ciliogenesis. RNAi-mediated knockdown of the protein causes reduced swimming motility and velocity. Display a reduction in the cilia beating frequency and an altered cilia waveform. Show absence of the outer and inner dynein arms. Belongs to the CFAP300 family.