Inhibition of Hedgehog signaling by direct binding of cyclopamine to Smoothened

Genes Dev. 2002 Nov 1;16(21):2743-8. doi: 10.1101/gad.1025302.

Abstract

The steroidal alkaloid cyclopamine has both teratogenic and antitumor activities arising from its ability to specifically block cellular responses to vertebrate Hedgehog signaling. We show here, using photoaffinity and fluorescent derivatives, that this inhibitory effect is mediated by direct binding of cyclopamine to the heptahelical bundle of Smoothened (Smo). Cyclopamine also can reverse the retention of partially misfolded Smo in the endoplasmic reticulum, presumably through binding-mediated effects on protein conformation. These observations reveal the mechanism of cyclopamine's teratogenic and antitumor activities and further suggest a role for small molecules in the physiological regulation of Smo.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Animals
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / toxicity
  • Binding Sites
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / physiology
  • Hedgehog Proteins
  • Mice
  • Protein Binding
  • Protein Conformation
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / drug effects
  • Receptors, Cell Surface / physiology*
  • Receptors, G-Protein-Coupled*
  • Signal Transduction / drug effects*
  • Smoothened Receptor
  • Teratogens / pharmacology
  • Teratogens / toxicity
  • Trans-Activators / physiology*
  • Veratrum Alkaloids / chemistry
  • Veratrum Alkaloids / pharmacology*
  • Veratrum Alkaloids / toxicity

Substances

  • Antineoplastic Agents
  • Hedgehog Proteins
  • Receptors, Cell Surface
  • Receptors, G-Protein-Coupled
  • Smo protein, mouse
  • Smoothened Receptor
  • Teratogens
  • Trans-Activators
  • Veratrum Alkaloids
  • cyclopamine