SH2 domain specificity and activity modified by a single residue.
Many intracellular targets of protein-tyrosine kinases possess Src homology 2 (SH2) domains that directly recognize phosphotyrosine-containing sites on autophosphorylated growth factor receptors and cytoplasmic proteins, and thereby mediate the activation of biochemical signalling pathways. SH2 domains possess relatively well conserved residues that form the phosphotyrosine-binding pocket, and more variable residues that are implicated in determining binding specificity by recognition of the three amino acids carboxy-terminal to phosphotyrosine (the +1 to +3 positions). One such residue, occupying the EF1 position of the +3-binding pocket, is a Thr in the SH2 domain of the Src tyrosine kinase, but is predicted to be a Trp in the SH2 domain of the Sem-5/drk/Grb2 adaptor protein. Here we report that changing this residue in the Src SH2 domain from Thr to Trp switches its selectivity to resemble that of the Sem-5/drk/Grb2 SH2 domain. Furthermore, this mutant Src SH2 domain effectively substitutes for the SH2 domain of the Sem-5 protein in activation of the Ras pathway in vivo. These results identify a residue that can modify SH2 selectivity, and indicate that the biological activity of an SH2 domain correlates with its binding specificity.
Marengere
L E
LE
Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
Songyang
Z
Z
Gish
G D
GD
Schaller
M D
MD
Parsons
J T
JT
Stern
M J
MJ
Cantley
L C
LC
Pawson
T
T
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051380:GRB2 Adaptor Protein; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism; D007301:Insect Hormones / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; D051380:GRB2 Adaptor Protein; D015801:Helminth Proteins; D007301:Insect Hormones; D011506:Proteins; C085751:Sem-5 protein, C elegans; C080530:drk protein, Drosophila; D013912:Threonine; D014364:Tryptophan; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)