How Does PTCH Function in the Hedgehog Signaling Pathway?
In the absence of Hh ligands, PTCH inhibits the activity of the Smoothened (SMO) protein, preventing the activation of downstream signaling pathways. When Hh ligands bind to PTCH, this inhibition is relieved, allowing SMO to activate the signaling cascade. This leads to the activation of Gli transcription factors, which regulate the expression of target genes involved in cell growth and differentiation.
