Required for the maintenance and formation of cilia. Plays an indirect role in hedgehog (Hh) signaling, cilia being required for all activity of the hedgehog pathway (By similarity). Interacts with IFT88 (By similarity). Interacts with IFT57 (By similarity). Interacts with RABL2/RABL2A; binds preferentially to GDP-bound RABL2 (By similarity). May interact with LHX3 and LHX4; the relevance of such interaction is however unclear in vivo. Highly expressed in the testis and pituitary cells. Belongs to the IFT172 family.