Patched (Ptc) is a conserved 12-pass transmembrane protein receptor that plays an obligate negative regulatory role in the Hedgehog signaling pathway in insects and vertebrates.
[2] The original mutations in the ptc gene were discovered in the fruit fly Drosophila melanogaster by 1995 Nobel Laureates Eric F. Wieschaus and Christiane Nusslein-Volhard and colleagues, and the gene was independently cloned in 1989 by Joan Hooper in the laboratory of Matthew P. Scott, and by Philip Ingham and colleagues.
In the absence of hedgehog, low levels of patched are sufficient to suppress activity of the signal transduction pathway.
When hedgehog is present, its cholesterol moiety binds to the sterol-sensing domain in patched, which then inhibits the activity of smoothened.
Mutated patched proteins have been implicated in a number of cancers including basal cell carcinoma, medulloblastoma, and rhabdomyosarcoma.