GRB2 Related Adaptor Protein 1 (GRAP1)

GRAP1 encodes a member of the GRB2/Sem5/Drk family. This member functions as a cytoplasmic signaling protein which contains an SH2 domain flanked by two SH3 domains. The SH2 domain interacts with ligand-activated receptors for stem cell factor and erythropoietin, and facilitates the formation of a stable complex with the BCR-ABL oncoprotein. This protein also associates with the Ras guanine nucleotide exchange factor SOS1 (son of sevenless homolog 1) through its N-terminal SH3 domain.GRAP also formed a stable complex via its SH2 domain with the BCR-ABL oncoprotein. Furthermore, GRAP associated, primarily through its N-terminal SH3 domain, with SOS1. Northern blot analysis of human tissues detected a 2.3-kb GRAP transcript primarily in thymus and spleen.