Centrosomal protein involved in centriole biogenesis. Acts as a scaffolding protein during early centriole biogenesis. Required for the targeting of centriole satellite proteins to centrosomes. Also required for centriole-centriole cohesion during interphase by acting as a platform protein for cep250 at the centriole (By similarity). During centriole biogenesis, it is concentrated within the proximal lumen of both parental centrioles and procentrioles. Belongs to the CEP135/TSGA10 family.