Required for cilia biogenesis. Appears to function within the multiple intraflagellar transport complex B (IFT-B). Key regulator of hedgehog signaling. Interacts with CLU/clusterin (PubMed:15480429). Interacts with UBXN10; the interaction is direct (PubMed:26389662). Expressed in testis, thyroid and trachea and to a lower extent in spinal cord and adrenal gland. Highly expressed in colon cancer and osteosarcoma cell lines. Associated with a number of cancers such as colon (PubMed:15480429) and bone cancer (PubMed:17203229). Possibly involved in polycystic kidney diseases (PubMed:15530380). Belongs to the CLUAP1 family. Intron retention. Truncated N-terminus.