Required to promote assembly of the transition zone in primary cilia. Acts by specifically recognizing and binding the axonemal microtubule. Localizes to the distal ends of centrioles before ciliogenesis and directly binds to axonemal microtubule, thereby promoting and restricting transition zone formation specifically at the cilia base. Required to mediate CEP290 association with microtubules (By similarity). Interacts with CPNE4 (PubMed:12522145). Interacts with alpha-tubulin. Interacts with CEP290 (By similarity). Localizes to the distal end of centrioles throughout the cell cycle. During ciliogenesis, found at the cilia base. Localizes to spindle microtubules during mitosis (By similarity). Belongs to the CEP162 family.