GRB2-related adapter protein 2 (GRAP2)

GRB2-related adapter protein 2 (GRAP2, also known as GADS) is an adaptor protein within the GRB2/Sem5/Drk family that plays a central role in leukocyte (immune cell)-specific protein tyrosine kinase signaling[2][5][1]. Structurally, it features a central SH2 domain flanked by two SH3 domains, and differs from closely related proteins by a unique 120-amino acid glutamine/proline-rich sequence in its C-terminal SH3 domain[4]. GRAP2 acts as a molecular bridge in T lymphocyte signaling by constitutively binding the adapter protein SLP-76 (LCP2), thereby facilitating the assembly of signal transduction complexes following T cell receptor and co-stimulatory receptor (e.g., CD28) engagement. Its main biological roles include orchestrating T cell activation, integrating immune cell signals, and regulating downstream pathways such as NF-AT and JNK signaling[2][4][7]. In cancer biology, particularly in lung adenocarcinoma (LUAD), GRAP2 functions as a tumor suppressor with low expression correlating to poor prognosis. Its expression correlates strongly with immune infiltration, and it regulates various immune response pathways and interactions with chemokines, MHC molecules, and other immune regulators, making it useful as a biomarker for prognosis and immune microenvironment characterization in certain cancers[3]. There are currently no known direct pharmacological modulators or clinical drugs targeting GRAP2, and its role is primarily as a signaling adaptor rather than directly as a therapeutic target[5][2][3].

Other names

GADSGRB2LGRIDGRPLGrf40GrbXGRBLGMonaAdapter protein GRIDGRB-2-like proteinSH3-SH2-SH3 adapter MonaGrowth factor receptor-binding proteinHematopoietic cell-associated adapter protein GrpLP38Protein GADS