Putative Killer Cell Immunoglobulin-Like Receptor Like Protein KIR3DP1 (KIR3DP1) Human Recombinant Protein

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 ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals. The ligands for several KIR proteins are subsets of HLA class I molecules; thus, KIR proteins are thought to play an important role in regulation of the immune response. This gene is one of the "framework" loci that is present on all haplotypes. This gene is considered to be a pseudogene based on the absence of transcription and it lacks several functional domains compared to other killer cell immunoglobulin-like receptors. A rare haplotype, the result of a recombinantion event, has two copies of this gene, one of which may encode a secreted protein. (PMID: 15580659)[provided by RefSeq, Mar 2011]

MiscellaneousPubMed: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.