NKG2A and NKG2C are type II transmembrane proteins with extracellular C-type lectin domains. These proteins heterodimerize with CD94 to form complexes that recognize HLA-E as ligand. The NKG2A/CD94 complex delivers an inhibitory signal resulting from ITIMs within the NKG2A cytoplasmic domain. NKG2C/CD94 provides an activating signal due to association with the ITAM-containing DAP12 adapter protein. These complexes are expressed on NK and T cell subsets.