Acts as a key negative regulator of ciliogenesis in collaboration with CCP110 by capping the mother centriole thereby preventing cilia formation (PubMed:17719545, PubMed:30375385). Required for recruitment of CCP110 to the centrosome (PubMed:17719545). Interacts with CALM1, CEP76, CCP110, KIF24, TALPID3. Via its interaction with CCP110, may indirectly interact with HERC2 and NEURL4 (PubMed:22261722). Interacts with MPHOSPH9 (PubMed:30375385). Recruited at the distal end of the mother centriole by MPHOSPH9. Sequence incomplete. Truncated N-terminus.