Role of Patched-1 Intracellular Domains in Canonical and Non-Canonical Hedgehog Signalling Events

• Main Author: Harvey, Malcolm
• Other Authors: Hamel, Paul A.
• Language: en_ca
• Published: 2013
• Subjects: Hedgehog signalling; Molecular Biology; 0307
• Online Access: http://hdl.handle.net/1807/42877

Patched-1 (Ptch1) is the primary receptor for Hedgehog (Hh) ligands and mediates both canonical and non-canonical Hh signalling. Previously, our lab identified that mice possessing a Ptch1 C-terminal truncation display blocked mammary gland development at puberty that is overcome by overexpression of activated c-src. Testing the hypothesis that this involves a direct interaction between Ptch1 and c-src, we identified through co-immunoprecipitation that Ptch1 and c-src associate in an Hh-dependent manner, and that the Ptch1 C-terminus regulates activation of c-src in response to Hh ligand. Since the effects of Ptch1 intracellular domain deletions on canonical Hh signalling are ill-defined, we assayed this through luciferase reporter assays and qRT-PCR. Transient assays revealed that the Ptch1 middle intracellular loop is required for response to ligand, while qRT-PCR from primary cells showed that C-terminal truncation impairs canonical Ptch1 function. Together, this indicates that the intracellular domains of Ptch1 mediate distinct canonical and non-canonical functions.