Acts as a key negative regulator of ciliogenesis in collaboration with CCP110 by capping the mother centriole thereby preventing cilia formation. Required for recruitment of CCP110 to the centrosome (By similarity). Interacts with CALM1, CEP76, CCP110, KIF24, TALPID3. Via its interaction with CCP110, may indirectly interact with HERC2 and NEURL4 (By similarity). Interacts with MPHOSPH9 (By similarity). Recruited at the distal end of the mother centriole by MPHOSPH9.