Inhibition of tetrameric Patched1 by Sonic Hedgehog through an asymmetric paradigm. Author Hongwu Qian, Pingping Cao, Miaohui Hu, Shuai Gao, Nieng Yan, Xin Gong Publication Year 2019 Type Journal Article Abstract The Hedgehog (Hh) pathway controls embryonic development and postnatal tissue maintenance and regeneration. Inhibition of Hh receptor Patched (Ptch) by the Hh ligands relieves suppression of signaling cascades. Here, we report the cryo-EM structure of tetrameric Ptch1 in complex with the palmitoylated N-terminal signaling domain of human Sonic hedgehog (ShhN) at a 4:2 stoichiometric ratio. The structure shows that four Ptch1 protomers are organized as a loose dimer of dimers. Each dimer binds to one ShhN through two distinct inhibitory interfaces, one mainly through the N-terminal peptide and the palmitoyl moiety of ShhN and the other through the Ca-mediated interface on ShhN. Map comparison reveals that the cholesteryl moiety of native ShhN occupies a recently identified extracellular steroid binding pocket in Ptch1. Our structure elucidates the tetrameric assembly of Ptch1 and suggests an asymmetric mode of action of the Hh ligands for inhibiting the potential cholesterol transport activity of Ptch1. Keywords Humans, Protein Binding, Models, Molecular, Ligands, Recombinant Proteins, HEK293 Cells, Protein Multimerization, Cryoelectron Microscopy, Hedgehog Proteins, Protein Domains, Cholesterol, Lipoylation, Patched-1 Receptor Journal Nat Commun Volume 10 Issue 1 Pages 2320 Date Published 2019 May 24 ISSN Number 2041-1723 DOI 10.1038/s41467-019-10234-9 Alternate Journal Nat Commun PMCID PMC6534611 PMID 31127104 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML