Growth factor receptor-binding protein 2 (GRB2) is a adaptor protein that is involved in RTK signal transduction. This gene is similar to the Sem5 gene of C.elegans, which is involved in the signal transduction pathway. This protein binds the epidermal growth factor receptor and contains one SH2 domain and two SH3 domains. The SH2 domain of GRB2 binds to tyrosine phosphorylated proteins such as EGFR, IRS-1, Shc and Gab1. The SH3 domain of GRB2 associates with Sos, which stimulates the GTP binding activity of Ras, leading to the activation of the MAP kinase and other signaling pathways.
