Expression, Purification, and Structure Determination of Human PTCH1-HH-N Complexes

Area of Science:

• Molecular Biology
• Structural Biology
• Cancer Research

Background:

• Patched-1 (PTCH1) is a tumor suppressor crucial for regulating the Hedgehog (HH) signaling pathway.
• PTCH1 acts as the receptor for HH ligands, and its mutations are linked to various human cancers.
• Understanding PTCH1's mechanism is vital for developing targeted cancer therapies.

Purpose of the Study:

• To express and purify a functional variant of Patched-1 (PTCH1), termed PTCH1*.
• To determine the structure of PTCH1* in complex with Sonic Hedgehog (SHH) ligand.
• To elucidate the structural basis of PTCH1-mediated HH signal regulation.

Main Methods:

• Protein expression and purification of PTCH1*.
• Assembly of PTCH1*-SHH complexes.
• Cryo-electron microscopy (cryo-EM) for structural determination.

Main Results:

• Successfully expressed and purified a nearly full-length functional PTCH1* variant.
• Assembled two distinct forms of PTCH1*-SHH complexes.
• Determined the structures of these complexes using cryo-EM, revealing molecular details of interaction.

Conclusions:

• The structural data provides novel insights into the mechanism of HH signal regulation by PTCH1.
• This work facilitates the rational design of novel cancer therapeutics targeting the HH pathway.
• The purified PTCH1* protein and determined structures serve as valuable resources for future research.