KIR2DL5A and KIR2DL5B are Killer cell immunoglobulin-like receptors (KIRs), 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. 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. KIR proteins are thought to play an important role in regulation of the immune response. Functionally, KIR2DL5A and KIR2DL5B are receptors on natural killer (NK) cells for HLA-C alleles and prevent cell lysis by inhibiting the activity of NK cells.
CD158 antigen-like family member F2; CD158F; CD158F2; killer cell Ig-like receptor; killer cell immunoglobulin-like receptor 2DLX; killer cell immunoglobulin-like receptor two domains long cytoplasmic tail 5; killer cell immunoglobulin-like receptor, two domains, long cytoplasmic tail, 5B; killer Ig receptor; killer-cell Ig-like receptor; KIR2DL5; KIR2DLX