Activation of the Raf-1 kinase cascade by coumermycin-induced dimerization

Nature. 1996 Sep 12;383(6596):178-81. doi: 10.1038/383178a0.


The Raf-1 serine/threonine kinase is a key component of the MAP kinase cascade, regulating both proliferation and commitment to cell fate. Raf activation is stimulated following its translocation to the plasma membrane, a process that ordinarily requires interaction with the membrane-localized GTPase, Ras-GTP. To investigate the mechanisms underlying Raf activation, we have developed a coumermycin-induced chemical dimerization method. We find that dimerization is by itself sufficient, in the absence of any membrane components, both to activate a modified Raf protein and to stimulate the MAP kinase cascade appropriately. As Ras-GTP-induced membrane localization increases the effective intracellular Raf concentration, our results indicate that homotypic oligomerization may ordinarily act to promote Raf activation in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Aminocoumarins
  • Animals
  • Biopolymers
  • Cell Line
  • Cell Membrane / enzymology
  • Coumarins / chemistry
  • Coumarins / pharmacology
  • DNA Gyrase
  • DNA Topoisomerases, Type II / metabolism
  • Enzyme Activation
  • MAP Kinase Kinase 1
  • Mice
  • Mitogen-Activated Protein Kinase Kinases*
  • Molecular Structure
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-raf
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Streptomyces
  • Transfection


  • Aminocoumarins
  • Biopolymers
  • Coumarins
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-raf
  • MAP Kinase Kinase 1
  • Map2k1 protein, mouse
  • Mitogen-Activated Protein Kinase Kinases
  • DNA Gyrase
  • DNA Topoisomerases, Type II
  • coumermycin