Involved in ciliogenesis (PubMed:32453716). It is required for appropriate acetylation and polyglutamylation of ciliary microtubules, and regulation of cilium length (PubMed:32453716). Interacts with microtubules and promotes microtubule polymerization via its HEAT repeat domains, especially those in TOG region 2 and 4 (By similarity). Interacts with ARMC9, CCDC66, CEP104 and CSPP1. Detected along the length of primary cilia and at the basal body. Colocalization with the cytoplasmic microtubule cytoskeleton upon heterologous expression is most likely an artifact. The TOG regions are composed of HEAT-type repeats that assemble into a solenoid structure. They mediate interaction with microtubules. The disease is caused by variants affecting the gene represented in this entry. Belongs to the Crescerin family. Extended N-terminus.