Intercellular signal essential for a variety of patterning events during development. Signal produced by the notochord that induces somite patterning, dorso-ventral patterning of the brain and early patterning of the developing eyes. Displays floor plate-inducing activity. Binds to the patched (PTC) receptor, which functions in association with smoothened (SMO), to activate the transcription of target genes. In the absence of SHH, PTC represses the constitutive signaling activity of SMO (By similarity).
