Diversity in KIR ligands and function KIRs inhibit NK cells effector functions upon the interaction with HLA molecules expressed on putative target cells. Using the membrane distal D0 domain, certain KIRs are now shown to bind DNA and activate TLR9 signaling in NK cells. Note that most KIRs are monomeric but that KIR3DL2 is actually a homo-dimeric receptor.