Structural basis for dimerization of the Grb10 Src homology 2 domain. Implications for ligand specificity

J Biol Chem. 2003 Apr 11;278(15):13257-64. doi: 10.1074/jbc.M212026200. Epub 2003 Jan 27.

Abstract

Grb7, Grb10, and Grb14 are members of a distinct family of adapter proteins that interact with various receptor tyrosine kinases upon receptor activation. Proteins in this family contain several modular signaling domains including a pleckstrin homology (PH) domain, a BPS (between PH and SH2) domain, and a C-terminal Src homology 2 (SH2) domain. Although SH2 domains are typically monomeric, we show that the Grb10 SH2 domain and also full-length Grb10 gamma are dimeric in solution under physiologic conditions. The crystal structure of the Grb10 SH2 domain at 1.65-A resolution reveals a non-covalent dimer whose interface comprises residues within and flanking the C-terminal alpha helix, which are conserved in the Grb7/Grb10/Grb14 family but not in other SH2 domains. Val-522 in the BG loop (BG3) and Asp-500 in the EF loop (EF1) are positioned to interfere with the binding of the P+3 residue of a phosphopeptide ligand. These structural features of the Grb10 SH2 domain will favor binding of dimeric, turn-containing phosphotyrosine sequences, such as the phosphorylated activation loops in the two beta subunits of the insulin and insulin-like growth factor-1 receptors. Moreover, the structure suggests the mechanism by which the Grb7 SH2 domain binds selectively to pTyr-1139 (pYVNQ) in Her2, which along with Grb7 is co-amplified in human breast cancers.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Binding Sites
  • Crystallography, X-Ray
  • Dimerization
  • ErbB Receptors / chemistry
  • ErbB Receptors / metabolism
  • GRB10 Adaptor Protein
  • GRB7 Adaptor Protein
  • Humans
  • Ligands
  • Molecular Sequence Data
  • Peptide Fragments / chemistry
  • Protein Conformation
  • Protein Structure, Secondary
  • Proteins / chemistry*
  • Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Solutions
  • Substrate Specificity
  • src Homology Domains*

Substances

  • Adaptor Proteins, Signal Transducing
  • GRB14 protein, human
  • GRB7 protein, human
  • Ligands
  • Peptide Fragments
  • Proteins
  • Solutions
  • GRB7 Adaptor Protein
  • GRB10 Adaptor Protein
  • ErbB Receptors