Essential for primary ciliogenesis and embryonic development, facilitating the activation of Hedgehog (Hh) signaling pathway. Disrupts the interaction of GLI2 and GLI3 with the negative regulator SUFU. Inhibiting SUFU's interaction with GLI2 promotes the entry of GLI2 into the nucleus, allowing it to activate Hh target gene expression. Disrupting SUFU's interaction with GLI3 prevents its conversion into the repressor form, leading to increased nuclear GLI3 and enhanced Hh signaling. Required for the proper development and structural integrity of photoreceptor outer segment disks, ensuring normal outer segment morphogenesis and survival of photoreceptors. . This is the function of TMEM216 (transmembrane protein 216, ENSG00000187049).