The SH2 (Src Homology 2) domain is a structurally conserved motif that contains two alpha helices and seven beta strands and is found in a variety of proteins that are involved in signal transduction throughout the cell. Specifically, the SH2 domain targets SH2 domain-containing proteins to tyrosinephosphorylated sites, an event that can trigger a protein-protein interaction cascade which may ultimately effect gene expression and cellular function. Shb (SH2 domain-containing adapter protein b), Shd (SH2 domain-containing adapter protein d), She (SH2 domain-containing adapter protein e) and Shf(SH2 domain-containing adapter protein f) are SH2 domain-containing proteins that play various roles throughout the cell.