HANGING IN THE BALANCE

Schematic of the different expressed KIR, their domain structures and their HLA class I ligands. The KIR in black are inhibitory and have immunoreceptor tyrosine inhibitory motifs (ITIMs). The KIR in red are activating and have a charged amino acid residue in the transmembrane region, illustrated with a “+” which permits them to pair with a signalling adaptor molecule. KIR2DL4 transduces an activating signal, but also has a single ITIM. The pseudogenes are not shown.