Controlling epidermal growth factor (EGF)-stimulated Ras activation in intact cells by a cell-permeable peptide mimicking phosphorylated EGF receptor

J Biol Chem. 1996 Nov 1;271(44):27456-61. doi: 10.1074/jbc.271.44.27456.


Epidermal growth factor (EGF)-stimulated Ras activation involves specific interactions between the EGF receptor (EGFR), the adaptor proteins Grb2 and Shc, and the nucleotide exchange factor Sos-1. Study and control of these protein-protein interactions in vivo can be greatly promoted by introducing intracellular reagents that mimic EGFR functions. Here, we showed that a synthetic phosphopeptide encompassing the autophosphorylation site 1068 of EGFR formed a complex with endogenous Grb2 after this peptide was delivered into intact cells by a cell-permeable peptide import technique. Consequently, this intracellular peptide inhibited EGF-induced EGFR/Grb2 associations but not EGFR/Shc or Shc/Grb2 associations. Peptide-mediated disruption of the EGF/Grb2/Sos-1 cascade led to reduced Ras activation and mitogen-activated protein kinase activation. These results indicate that the binding of Grb2 to the phosphorylated Tyr-1068 of EGFR is crucial to the EGF-induced Ras/mitogen-activated protein kinase signaling pathway. The application of cell-permeable peptides to this study demonstrates a useful biochemical tool to probe and control various intracellular processes involved in signal transduction and gene transcription.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Sequence
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cell Membrane Permeability
  • Epidermal Growth Factor / pharmacology*
  • ErbB Receptors / metabolism*
  • Fluorescent Antibody Technique, Indirect
  • GRB2 Adaptor Protein
  • Humans
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Peptide Fragments / chemistry
  • Phosphopeptides / chemistry
  • Phosphopeptides / pharmacology*
  • Proteins / metabolism*
  • Signal Transduction
  • Transcription, Genetic
  • ras Proteins / metabolism*


  • Adaptor Proteins, Signal Transducing
  • GRB2 Adaptor Protein
  • GRB2 protein, human
  • Grb2 protein, mouse
  • Peptide Fragments
  • Phosphopeptides
  • Proteins
  • Epidermal Growth Factor
  • ErbB Receptors
  • Calcium-Calmodulin-Dependent Protein Kinases
  • ras Proteins