SH2D1A is a protein that plays a major role in the bidirectional stimulation of T and B cells. It associates with the signaling lymphocyte-activation molecule, thereby acting as an inhibitor of this transmembrane protein by blocking the recruitment of the SH2-domain-containing signal-transduction molecule SHP-2 to its docking site. This protein can also bind to other related surface molecules that are expressed on activated T, B and NK cells, thereby modifying signal transduction pathways in these cells. Mutations in SH2D1A gene cause lymphoproliferative syndrome X-linked type 1 or Duncan disease, a rare immunodeficiency characterized by extreme susceptibility to infection with Epstein-Barr virus, with symptoms including severe mononucleosis and malignant lymphoma. Protein Interaction Partner: LHX4, TNK2, UBC, LYN, MAPK11, MAPK1, ERBB3, EGFR, MAPK14, CD244, ELAVL1, SLAMF7, SLAMF6, ARHGEF7, CD84, SLAMF1, DOK1, FYB, LY9, ARHGEF6, LCK, FYN, GRB2, Protein Size: 125