Converse conformational control of smoothened activity by structurally related small molecules

J Biol Chem. 2009 Jul 31;284(31):20876-84. doi: 10.1074/jbc.M807648200. Epub 2009 Apr 14.

Abstract

The seven-pass transmembrane protein Smoothened (Smo) is an essential component of the Hedgehog (Hh) signaling pathway that is critically involved in normal animal development as well as pathological malignancies. In studying Hh-related biological processes, it would be highly desirable if Smo activity could be instantly switched between activation and inhibition. Using Gli1-dependent GFP transgenic zebrafish and in vitro biochemical assays, we identified and characterized two potent Smo inhibitors, SANT74 and 75 (Smoothened antagonist 74 and 75), by screening a small molecule library designed based on the scaffold of Smo agonist SAG. These compounds are structural analogs of SAG with the methyl group substituted by a propyl or allyl group in SANTs. We show that SANTs and SAG exert opposite effects on Smo activity by regulating protein conformation. Our study represents the first demonstration of conformational regulation of Smo by small molecule analogs, and the combinational use of these Smo modulators in a temporal controlled fashion should be useful for studying Hh biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Embryo, Nonmammalian / drug effects
  • Embryo, Nonmammalian / metabolism
  • Green Fluorescent Proteins / metabolism
  • Hedgehog Proteins / metabolism
  • Humans
  • Mice
  • NIH 3T3 Cells
  • Oncogene Proteins / metabolism
  • Protein Conformation / drug effects
  • Receptors, G-Protein-Coupled / agonists
  • Receptors, G-Protein-Coupled / antagonists & inhibitors
  • Receptors, G-Protein-Coupled / chemistry*
  • Receptors, G-Protein-Coupled / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Small Molecule Libraries / chemistry*
  • Small Molecule Libraries / pharmacology
  • Smoothened Receptor
  • Trans-Activators / metabolism
  • Zebrafish / embryology
  • Zebrafish / metabolism
  • Zinc Finger Protein GLI1

Substances

  • Hedgehog Proteins
  • Oncogene Proteins
  • Receptors, G-Protein-Coupled
  • Recombinant Fusion Proteins
  • Small Molecule Libraries
  • Smo protein, mouse
  • Smoothened Receptor
  • Trans-Activators
  • Zinc Finger Protein GLI1
  • Green Fluorescent Proteins