A region in Shc distinct from the SH2 domain can bind tyrosine-phosphorylated growth factor receptors.

Shc is a ubiquitously expressed Src homology 2 (SH2) domain protein that can transform fibroblasts and differentiate PC12 cells in a Ras-dependent fashion. Shc binds a variety of tyrosine-phosphorylated growth factor receptors presumably via its carboxyl-terminal SH2 domain. We cloned a fragment of Shc when screening a bacterial expression library with tyrosine-phosphorylated epidermal growth factor (EGF) receptor. Surprisingly, this fragment encodes the amino terminus of Shc, a region that has no significant similarity to an SH2 domain. When expressed as a glutathione S-transferase fusion protein, this amino-terminal domain binds to autophosphorylated EGF receptor, as well as HER2/neu and TrkA receptors. This fragment acts like an SH2 domain in that it does not bind non-phosphorylated EGF receptor or EGF receptor with all tyrosine phosphorylation sites mutated or deleted. Our data define a novel domain in Shc that has the potential to interact with growth factor receptors and other tyrosine-phosphorylated proteins.