GRAP2/GADS (Grb2-related adaptor protein 2 / Grb2-related adaptor downstream of Shc) is a cytoplasmic adaptor protein containing N- and C-terminal SH3 domains flanking a central SH2 domain and a proline/glutamine-rich region. It is expressed predominantly in lymphoid tissue and hematopoietic cells, particularly in T cells. GRAP2/GADS plays a pivotal role during the early events of T cell signal transduction by recruiting the adaptor protein SLP-76 and its associated molecules, such as Vav, Nck, Itk, and ADAP, to the transmembrane adaptor protein LAT. GRAP2/GADS also binds several other signaling proteins, namely Gab2, HPK1 (hematopoietic progenitor kinase 1), and Cbl. Unlike similar adaptor protein Grb2, GRAP2/GADS shows higher selectivity when binding to the particular phosphorylated tyrosines of LAT adaptor.
