Killer cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer cells and subsets of T cells. The KIR genes are polymorphic and highly homologous and they are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). The gene content of the KIR gene cluster varies among haplotypes, although several "framework" genes are found in all haplotypes (KIR3DL3, KIR3DP1, KIR3DL4, KIR3DL2). The KIR proteins are classified by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM), while KIR proteins with the short cytoplasmic domain lack the
Function:
Function:Receptor on natural killer (NK) cells for HLA-C alleles. Inhibits the activity of NK cells thus preventing cell lysis.,miscellaneous:PubMed:15580659, identified a chromosomal rearrangement producing a recombinant gene composed of the promoter and first exon of KIR2DL5A fused to KIR3DP1 which was originally thought to be a pseudogene. This leads to the expression in 4.5 percent of a Spanish Caucasoid population of an mRNA which may encode a chimeric protein KIR2DL5A/KIR3DP1.,similarity:Belongs to the immunoglobulin superfamily.,similarity:Contains 2 Ig-like C2-type (immunoglobulin-like) domains.,similarity:Contains 3 Ig-like C2-type (immunoglobulin-like) domains.,tissue specificity:Expressed in peripheral blood cells.,
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Cellular Localization:
Cell membrane; Single-pass type I membrane protein.