GRB2-associated-binding protein 2 (GAB2)

GRB2-associated-binding protein 2 (GAB2) is a large, multi-site docking/adaptor protein of approximately 97–100 kDa, encoded by the *GAB2* gene on chromosome 11q13.4–q13.5. It features an N-terminal Pleckstrin Homology (PH) domain, a central proline-rich domain with multiple PXXP motifs, and a C-terminal region with several tyrosine phosphorylation sites that serve as docking points for SH2-domain-containing signaling molecules. GAB2 mediates the integration and amplification of intracellular signals from receptor tyrosine kinases, cytokine receptors, G protein-coupled receptors, and immune recognition receptors. Through its phosphorylation-dependent recruitment of effectors such as SHP2, PI3K (p85 subunit), PLγ, Crk, and others, GAB2 controls pathways governing cell growth, survival, migration, apoptosis, and differentiation. GAB2 is ubiquitously expressed but particularly abundant in the brain, kidney, lung, heart, testis, and ovary. Dysregulation and aberrant signaling via GAB2 are linked to multiple human diseases, including several cancers and Alzheimer’s disease. GAB2 acts as a signaling hub, recruiting proteins via SH2 and SH3 domains to relay and regulate cues from the cell surface to diverse intracellular pathways, notably the PI3K/Akt and Ras/MAPK cascades. While no specific GAB2-targeting drugs are currently approved, it is a focus for drug development efforts due to its fundamental role in cancer biology and its emerging biomarker status in disease contexts.

Other names

Grb2-associated binder 2Growth factor receptor-bound protein 2-associated protein 2KIAA0571pp100GAB2

Proposed mechanisms include inhibition of protein-protein interactions (blockade of SH2/SH3 domain-mediated interactions) and disruption of phosphorylation sites necessary for effector recruitment. Indirect effects via drugs that target upstream (RTKs) or downstream signaling pathway components (e.g., PI3K/Akt, SHP2 inhibitors) may modulate GAB2 function.