SH2 domain-containing protein 1B (SH2D1B)

SH2 domain-containing protein 1B (SH2D1B, also known as EAT-2) is an intracellular adaptor protein characterized by a single Src homology 2 (SH2) domain and a short C-terminal tail[1][2][3][5]. It plays a central role in modulating signal transduction mediated by signaling lymphocytic activation molecule (SLAM) family receptors, particularly in natural killer (NK) cells and antigen-presenting cells[1][2][3][5][6]. By binding phosphotyrosine residues on SLAM family receptor tails via its SH2 domain, SH2D1B regulates critical pathways including calcium flux, phospholipase Cγ activation, and ERK signaling, which promote polarization and exocytosis of cytotoxic granules in NK cells[1][2][3][5]. This enhances NK cell cytotoxicity and regulation of immune responses independent of the related adaptor SAP (SH2D1A)[1][5][6]. Overexpression of SH2D1B can boost pro-inflammatory cytokine secretion, antigen presentation, dendritic cell maturation, and monocyte phagocytosis, contributing to both innate and adaptive immunity[1]. SH2D1B is upregulated in some cancers, notably Ewing's sarcoma via the EWS/FLI1 fusion gene, and aberrant function or expression may be involved in immunodeficiencies and tumor immune evasion[4][6]. There are currently no known drugs that directly target SH2D1B, nor established mechanisms of action or clinical biomarkers involving it, but its role in immune modulation highlights potential as a therapeutic or diagnostic target in cancer and immunological disorders[1][4][5][6].

Other names

EAT-2EAT2EWS/FLI1-activated transcript 2SH2 domain-containing molecule EAT2SH21B_HUMAN