Grb2-independent recruitment of Gab1 requires the C-terminal lobe and structural integrity of the Met receptor kinase domain

J Biol Chem. 2003 Aug 8;278(32):30083-90. doi: 10.1074/jbc.M302675200. Epub 2003 May 22.

Abstract

The Gab1 docking protein forms a platform for the assembly of a multiprotein signaling complex downstream from receptor tyrosine kinases. In general, recruitment of Gab1 occurs indirectly, via the adapter protein Grb2. In addition, Gab1 interacts with the Met/hepatocyte growth factor receptor in a Grb2-independent manner. This interaction requires a Met binding domain (MBD) in Gab1 and is essential for Met-mediated epithelial morphogenesis. The Gab1 MBD has been proposed to act as a phosphotyrosine binding domain that binds Tyr-1349 in the Met receptor. We show that a 16-amino acid motif within the Gab1 MBD is sufficient for interaction with the Met receptor, suggesting that it is unlikely that the Gab1 MBD forms a structured domain. Alternatively, the structural integrity of the Met receptor, and residues upstream of Tyr-1349 located in the C-terminal lobe of the kinase domain, are required for Grb2-independent interaction with the Gab1 MBD. Moreover, the substitution of Tyr-1349 with an acidic residue allows for the recruitment of the Gab1 MBD and for phosphorylation of Gab1. We propose that Gab1 and the Met receptor interact in a novel manner, such that the activated kinase domain of Met and the negative charge of phosphotyrosine 1349 engage the Gab1 MBD as an extended peptide ligand.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Binding Sites
  • Blotting, Western
  • Cell Line
  • GRB2 Adaptor Protein
  • Glutathione Transferase / metabolism
  • Humans
  • Ligands
  • Microscopy, Fluorescence
  • Models, Biological
  • Models, Molecular
  • Molecular Sequence Data
  • Peptides / chemistry
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Plasmids / metabolism
  • Precipitin Tests
  • Protein Binding
  • Protein Structure, Tertiary
  • Proteins / metabolism*
  • Proto-Oncogene Proteins c-met / chemistry*
  • Recombinant Fusion Proteins / metabolism
  • Transfection
  • Tyrosine / chemistry

Substances

  • Adaptor Proteins, Signal Transducing
  • GAB1 protein, human
  • GRB2 Adaptor Protein
  • GRB2 protein, human
  • Ligands
  • Peptides
  • Phosphoproteins
  • Proteins
  • Recombinant Fusion Proteins
  • Tyrosine
  • Glutathione Transferase
  • Proto-Oncogene Proteins c-met