Killer Cell Immunoglobulin Like Receptor 2DS1 (KIR2DS1)

The KIR2DS1 cDNA encodes a deduced 304-amino acid transmembrane protein. Sequence analysis revealed that the extracellular domain of KIR2D p50 receptors is similar to that of KIR2D p58 receptors; however, in the transmembrane region, there is a charged lysine residue consistently encoded by AAA, and the cytoplasmic tail has only 39 amino acids with no ITIM (immunoreceptor tyrosine-based inhibitory motif). KIRs with short cytoplasmic tails are associated with NK cell triggering rather than inhibition. Immunoprecipitation and Western blot analyses of KIR2DS1 expressed in COS cells revealed a 50-kD protein. Flow cytometric analysis confirmed surface expression of KIR2DS1. Biassoni et al. (1996) pointed out that receptors with identical HLA-C allele specificity can mediate opposite functions owing to their different transmembrane/cytoplasmic regions.