NKG2 contains C-type lectin domain and belongs to the killer cell lectin-like receptor (KLR) family. KLR family is a group of transmembrane proteins preferentially expressed in natural killer (NK) cells. NK cells are a distinct lineage of lymphocytes that mediate cytotoxic activity and secrete cytokines upon immune stimulation. CD94, also known as killer cell lectin-like receptor subfamily D member 1 (KLRD1), is expressed on the surface of NK cells in the innate immune system. CD94 plays a role as a receptor for the recognition of MHC class I Human Leukocyte Antigen (HLA)-E molecules by NK cells and some cytotoxic T-cells. CD94 can form disulfide-bonded heterodimer with NKG2 on the surface of NK cells. The NKG2/CD94 complex interacts with HLA-E on target cells and inhibits the cytotoxic activity of NK cells to prevent cell lysis.