GRB7, a SH2 domain protein, has a single SH2 domain at its C-terminal, a central region with similarity to Ras GAP, and a proline-rich N terminus. A related SH2 domain-containing protein, GRB10, exhibits a high degree of homology with GRB7. GRB10 undergoes serine but not tyrosine phosphorylation in response to EGF treatment, but appears to bind to the EGF receptor poorly. GRB10 maps to mouse chromosome 11, in close proximity to the EGF receptor. Similarly, GRB7 maps to the same mouse chromosome near the EGF receptor-related protein HER2.