Transmembrane component of the tectonic-like complex, a complex localized at the transition zone of primary cilia and acting as a barrier that prevents diffusion of transmembrane proteins between the cilia and plasma membranes. Required for ciliogenesis and sonic hedgehog/SHH signaling (By similarity). Part of the tectonic-like complex (also named B9 complex). Interacts with TMEM107. Localizes to the transition zone of primary cilia; SEPT2 is required for localization to the transition zone. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the TMEM231 family.