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 (By similarity). Detected in embryonic presomitic mesoderm, neuroectoderm, tissue surrounding the notochord, ventral neural tube. At all stages, expression corresponds to the localization of SHH. First detected during gastrulation. By 36 hours, PTC1 appears in the first branchial arch and the posterior mesenchyme of the fin bud; by 48 hours, in the hindbrain and foregut. Activated by Sonic hedgehog. Glycosylation is necessary for SHH binding. Belongs to the patched family.