Effects of Raf Dimerization and Its Inhibition on Normal and Disease-Associated Raf Signaling

Mol Cell. 2013 Feb 21;49(4):751-8. doi: 10.1016/j.molcel.2012.12.018. Epub 2013 Jan 24.

Abstract

Raf kinases are essential for normal Ras-Raf-MEK-ERK pathway signaling, and activating mutations in components of this pathway are associated with a variety of human cancers, as well as the related developmental disorders Noonan, LEOPARD, and cardiofaciocutaneous syndromes. Although the Raf kinases are known to dimerize during normal and disease-associated Raf signaling, the functional significance of Raf dimerization has not been fully elucidated. Here, using mutational analysis and a peptide inhibitor, we show that dimerization is required for normal Ras-dependent Raf activation and for the biological function of disease-associated Raf mutants with moderate, low, or impaired kinase activity. However, dimerization is not needed for the function of B-Raf mutants with high catalytic activity, such as V600E-B-Raf. Importantly, we find that a dimer interface peptide can effectively block Raf dimerization and inhibit Raf signaling when dimerization is required for Raf function, thus identifying the Raf dimer interface as a therapeutic target.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Cell Line
  • Enzyme Activation
  • Epidermal Growth Factor / physiology
  • Humans
  • MAP Kinase Signaling System*
  • Mice
  • Mutagenesis, Site-Directed
  • Mutation, Missense
  • Neoplasms / enzymology
  • Peptide Fragments / pharmacology
  • Platelet-Derived Growth Factor / physiology
  • Protein Interaction Domains and Motifs
  • Protein Kinase Inhibitors / pharmacology
  • Protein Multimerization
  • raf Kinases / antagonists & inhibitors
  • raf Kinases / chemistry
  • raf Kinases / genetics
  • raf Kinases / metabolism*
  • ras Proteins / metabolism

Substances

  • Peptide Fragments
  • Platelet-Derived Growth Factor
  • Protein Kinase Inhibitors
  • Epidermal Growth Factor
  • raf Kinases
  • ras Proteins