KLRK1 (Killer Cell Lectin Like Receptor K1): KLRK1 is a gene that encodes an activating receptor present on natural killer (NK) cells and some T cells. It plays a key role in immune surveillance by recognizing stress-induced ligands on target cells, which triggers the elimination of infected or transformed cells. KLRK1 is essential for the body’s defense against viral infections and certain cancers.