Component of the intraflagellar transport (IFT) complex B required for transport of proteins in the motile cilium (PubMed:12651157, PubMed:28479320). May be required for ciliary entrance and transport of specific ciliary cargo proteins such as che-3 which are related to motility (PubMed:28479320). Required for the formation of chemosensory cilia that detect chemosensory cues (PubMed:12651157). Component of the IFT complex B composed of at least che-2, che-13, dyf-1, dyf-3, dyf-6, dyf-11, dyf-13, ift-20, ift-74, ift-81, ifta-2, osm-1, osm-5 and osm-6. Moves along the axoneme. Regulated by the RFX-type transcription factor daf-19. Worms display defects in ciliary structure resulting in defects in ability and osmotic avoidance behavior. It also affects the localization of IFT complex B proteins, osm-5 and osm-6. Shortened axonemes of all classes of sensory cilia in the head. Required for mating. Belongs to the IFT57 family.