Natural killer cell receptor 2B4, 2B4, NK cell activation-inducing ligand, NAIL NK cell type I receptor protein 2B4, NKR2B4, h2B4, SLAM family member 4, SLAMF4, Signaling lymphocytic activation molecule 4, CD244
CD244 (Natural killer (NK) cell receptor 2B4/SLAMF4) is an Ig superfamily signaling lymphocyte activation molecule (SLAM) receptor. Like all SLAM family receptors, it has an extracellular segment with two immunoglobulin (Ig)-like domains, and a cytoplasmic domain containing four immunoreceptor tyrosine-based switch motifs. CD244 does not act as a selfligand similar to other SLAM family receptors. It binds CD48, a transmembrane receptor ubiquitously expressed on hematopoietic cells. CD244 activity is controlled by the presence or absence of small cytoplasmic adapter proteins, SH2D1A/SAP and/or SH2D1B/EAT-2. Downstream signaling involves predominantly VAV1, and, to a lesser degree, INPP5D/SHIP1 and CBL. Activation of CD244 stimulates NK cell cytotoxicity, production of IFN-gamma and granule exocytosis. CD244 is involved in the regulation of CD8+ T-cell proliferation, and inhibits inflammatory responses in dendritic cells (DCs). In cancers, CD244 shows increased expression in intratumoral DCs and myeloid suppressor cells, and anti-CD244 therapies may increase infiltrating T-cells and impair tumor growth.
