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 sensory cilia biogenesis (PubMed:15713455). 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. Expressed in a subset of sensory neurons including eight pairs of amphid neurons (ASE, ADF, ASG, ASH, ASI, ASJ, ASK and ADL), six inner labial neurons (IL2s) and two pairs of phasmid neurons (PHA and PHB). Cilia of at least eight pairs of amphid neurons from mutant dyf(m185) animals are truncated at a middle segment, and empty amphidial sockets were seen indicating cilium structural abnormalities. Belongs to the CLUAP1 family.