Natural killer cell lectin-like receptor subfamily K member 1 (NKG2D) (NKG2D)

Natural killer cell lectin-like receptor subfamily K member 1 (NKG2D) is a potent activating receptor expressed on the surface of natural killer (NK) cells, CD8+ T cells, and certain γδ T cells (UniProt P26718) [1]. It functions as a primary sensor for "induced-self" ligands, such as MICA, MICB, and the ULBP family, which are typically upregulated in response to cellular stress, viral infection, or malignant transformation (PubMed: 29662490) [2]. Upon ligand binding, NKG2D signals through the DAP10 adapter protein to trigger the release of cytotoxic granules and pro-inflammatory cytokines, facilitating the elimination of abnormal cells (PubMed: 30116238) [3]. In oncology, NKG2D is a major focus for immunotherapy, with strategies including CAR-T and CAR-NK cells that utilize the NKG2D extracellular domain to target a broad range of ligand-positive tumors (ClinicalTrials.gov: NCT03018405) [4]. However, the efficacy of these therapies can be hindered by tumor-mediated shedding of ligands, which acts as a decoy and leads to the downregulation of the receptor on effector cells (PubMed: 28473511) [5]. Additionally, NKG2D overactivation is implicated in the pathogenesis of autoimmune conditions like celiac disease and rheumatoid arthritis, where it contributes to chronic inflammation and tissue damage (PubMed: 25637456) [6].

Other names

KLRK1CD314NKG2-D type II integral membrane proteinKiller cell lectin-like receptor subfamily K member 1NKG2-D-activating NK receptor

Activation of NK cells and T cells through DAP10-mediated signaling to induce cytotoxicity and cytokine production against ligand-expressing cells; or therapeutic blockade of the receptor to prevent pathological immune activation in autoimmune diseases.