SH2D3A (SH2 domain containing 3A), also known as novel SH2-containing protein 1, is a 576 amino acid protein that is thought to play a role in JNK activation. SH2D3A interacts with p130 Cas and is found at low levels in fetal kidney, fetal lung, placenta, adult pancreas, kidney and lung. Subject to post-translational phosphorylation on multiple tyrosine residues, SH2D3A contains one Src homology 2 (SH2) domain. SH2 domains bind to tyrosine-phosphorylated regions of target proteins, frequently linking activated growth factors to putative signal transduction proteins.