Natural killer cell receptor subunit CD94 (CD94)

Natural killer cell receptor subunit CD94 is a type II transmembrane C-type lectin-like receptor predominantly found on the surface of natural killer (NK) cells and some CD8+ T-lymphocytes[1][3][2]. It does not independently function as a receptor but forms disulfide-bonded heterodimers with NKG2 family members (notably NKG2A or NKG2C), generating receptors that deliver inhibitory or activating signals to NK cells[3][5][4]. The primary ligand for the CD94/NKG2 receptor complex is the nonclassical MHC class I molecule HLA-E (humans) or Qa-1 (mouse), allowing NK cells to monitor the expression of MHC class I molecules, a process critical for discriminating healthy from stressed or infected cells[2][4]. Structurally, CD94 features a unique variant of the C-type lectin fold and altered carbohydrate-binding and Ca2+ binding capacities[1]. CD94/NKG2A heterodimers deliver inhibitory signals upon binding to HLA-E, largely mediated through immunoreceptor tyrosine-based inhibitory motifs (ITIMs) on NKG2A[2][4]. Dysregulation of CD94-containing receptors is implicated in tumor immune evasion, chronic infection, and may be therapeutically targeted to boost immune responses in cancer and viral diseases[4][5].

Other names

Killer cell lectin-like receptor subfamily E member 1KLRD1NK cell receptor subunit CD94Cluster of Differentiation 94

Inhibition of inhibitory signaling to boost natural killer (NK) cell and CD8+ T-cell cytotoxic activity (for drugs targeting NKG2A/CD94 complex)