Component of the intraflagellar transport (IFT) complex B required for transport of proteins in the motile cilium (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 maintenance and formation of chemosensory cilia that detect chemosensory cues (PubMed:10545497). 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. Emerges from the transition zones and move in a bidirectional fashion along the sensory cilia, displaying anterograde movement from the transition zone toward the tip of the ciliary axoneme and retrograde movement from the cilium tip back toward the transition zone. Expressed in amphid and phasmid chemosensory neurons, where it appears to concentrate at the base of the transition zones, which correspond to the basal bodies of motile and sensory cilia. Moves in the retrograde direction along cilia and dendrites, suggesting that it is retrieved from the distal endings of the cilia by a retrograde transport pathway that moves it along cilia and then dendrites, back to the neuronal cell body. Worms display defects in ciliary structure resulting in defects in ability and osmotic avoidance behavior. Belongs to the IFT172 family.