Acts as a receptor for sonic hedgehog (SHH), indian hedgehog (IHH) and desert hedgehog (DHH). Associates with the smoothened protein (SMO) to transduce the hedgehog's proteins signal. Seems to have a tumor suppressor function, as inactivation of this protein is probably a necessary, if not sufficient step for tumorigenesis. Interacts with SNX17 (PubMed:15769472). Interacts with IHH (PubMed:21537345). Interacts with G-protein coupled receptor GPR37L1 (By similarity). In the adult, expressed in brain, lung, liver, heart, placenta, skeletal muscle, pancreas and kidney. Expressed in tumor cells but not in normal skin. In the embryo, found in all major target tissues of sonic hedgehog, such as the ventral neural tube, somites, and tissues surrounding the zone of polarizing activity of the limb bud. Glycosylation is necessary for SHH binding. In the absence of Hh ligands, ubiquitination by ITCH at Lys-1426 promotes endocytosis and both proteasomal and lysosomal degradation. The disease may be caused by variants affecting the gene represented in this entry. 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 patched family.