GRAP2 Protein

Background

GRB2 is an adaptor protein that links receptor tyrosine kinases (RTKs) to downstream signaling pathways, including Ras/MAPK and PI3K/Akt. It consists of one SH2 domain flanked by two SH3 domains, enabling it to interact with phosphorylated tyrosines and proline-rich regions of target proteins. GRB2 primarily binds to proteins like SOS (a Ras GEF), Shc, and PLCγ, facilitating Ras activation and subsequent signaling for cell growth, proliferation, and differentiation. GRB2 is essential for embryonic development, cellular homeostasis, and immune responses. Dysregulation of GRB2 contributes to oncogenesis, particularly in breast, lung, and gastric cancers, where it enhances cell proliferation and survival through constitutive Ras signaling. GRB2 also plays roles in immune cell signaling, particularly T-cell receptor activation and cytokine production. Knockout models demonstrate embryonic lethality, highlighting its critical function in cellular signaling and development.