Component of the intraflagellar transport (IFT) complex B: together with IFT81, forms a tubulin-binding module that specifically mediates transport of tubulin within the cilium (PubMed:23990561). Binds beta-tubulin via its basic region (PubMed:23990561). Required for ciliogenesis (PubMed:23990561). Essential for flagellogenesis during spermatogenesis (PubMed:33689014).
