GRB2/A0126

GRB2, also known as A0126, is an adapter protein encoded in five exons on human chromosome 17q24-25.

GRB2, also known as A0126, is an adapter protein encoded in five exons on human chromosome 17q24-25. GRB2 contains an SH2 domain and two SH3 domains and links growth factor receptors with the Ras pathway. It appears to participate in activation of extracellular signal-regulated kinase 1, ERK1 (mitogen-activated protein kinase, MAPK1) and ERK2 (MAPK3). GRB2 has been found to interact with dopamine receptors D3 and D4, as well as ephrin receptors B2 and B6. Mutants in mice showed that GRB2 is required for differentiation of endodermal cells. Targeted homozygous deletion of exons 2 and 3 resulted in embryonic lethality in mice, while heterozygotes showed no abnormal phenotype.