Killer-cell immunoglobulin-like receptors (KIRs), are a family of type I transmembrane glycoproteins expressed on the plasma membrane of natural killer (NK) cells and a minority of T cells. At least 15 genes and 2 pseudogenes encoding KIR map in a 150-kb region of the leukocyte receptor complex (LRC) on human chromosome 19q13.4.
An immunoreceptor tyrosine-based inhibitory motif (ITIM), is a conserved sequence of amino acids that is found intracellularly in the cytoplasmic domains of many inhibitory receptors of the non-catalytic tyrosine-phosphorylated receptor family found on immune cells. These immune cells include T cells, B cells, NK cells, dendritic cells, macrophages and mast cells. ITIMs have similar structures of S/I/V/LxYxxI/V/L, where x is any amino acid, Y is a tyrosine residue that can be phosphorylated, S is the amino acid serine, I is the amino acid isoleucine, and V is the amino acid valine. ITIMs recruit SH2 domain-containing phosphatases, which inhibit cellular activation. ITIM-containing receptors often serve to target immunoreceptor tyrosine-based activation motif (ITAM)-containing receptors, resulting in an innate inhibition mechanism within cells. ITIM bearing receptors have important role in regulation of immune system allowing negative regulation at different levels of the immune response.
Leukocyte immunoglobulin-like receptor subfamily B member 1 is a protein that in humans is encoded by the LILRB1 gene.
HLA class I histocompatibility antigen, alpha chain F is a protein that in humans is encoded by the HLA-F gene. It is an empty intracellular molecule that encodes a non-classical heavy chain anchored to the membrane and forming a heterodimer with a β-2 microglobulin light chain. It belongs to the HLA class I heavy chain paralogues that separate from most of the HLA heavy chains. HLA-F is localized in the endoplasmic reticulum and Golgi apparatus, and is also unique in the sense that it exhibits few polymorphisms in the human population relative to the other HLA genes; however, there have been found different isoforms from numerous transcript variants found for the HLA-F gene. Its pathways include IFN-gamma signaling and CDK-mediated phosphorylation and removal of the Saccharomycescerevisiae Cdc6 protein, which is crucial for functional DNA replication.
Killer cell immunoglobulin-like receptor 2DL1 is a protein that in humans is encoded by the KIR2DL1 gene.
Killer cell immunoglobulin-like receptor 2DL4 is a protein that in humans is encoded by the KIR2DL4 gene.
Leukocyte-associated immunoglobulin-like receptor 1 is a protein that in humans is encoded by the LAIR1 gene. LAIR1 has also been designated as CD305.
Leukocyte immunoglobulin-like receptor subfamily B member 2 is a protein that in humans is encoded by the LILRB2 gene.
Leukocyte immunoglobulin-like receptor subfamily B member 4 is a protein that in humans is encoded by the LILRB4 gene.
Killer cell immunoglobulin-like receptor 3DL2 is a protein that in humans is encoded by the KIR3DL2 gene.
Killer cell immunoglobulin-like receptor 2DS4 is a protein that in humans is encoded by the KIR2DS4 gene.
Natural cytotoxicity triggering receptor 2 is a protein that in humans is encoded by the NCR2 gene. NCR2 has also been designated as CD336, NKp44, NKP44; NK-p44, LY95, and dJ149M18.1.
Leukocyte immunoglobulin-like receptor subfamily B member 3 is a protein that in humans is encoded by the LILRB3 gene.
Leukocyte immunoglobulin-like receptor subfamily A member 3 (LILR-A3) also known as CD85 antigen-like family member E (CD85e), immunoglobulin-like transcript 6 (ILT-6), and leukocyte immunoglobulin-like receptor 4 (LIR-4) is a protein that in humans is encoded by the LILRA3 gene located within the leukocyte receptor complex on chromosome 19q13.4. Unlike many of its family, LILRA3 lacks a transmembrane domain. The function of LILRA3 is currently unknown; however, it is highly homologous to other LILR genes, and can bind human leukocyte antigen (HLA) class I. Therefore, if secreted, the LILRA3 might impair interactions of membrane-bound LILRs with their HLA ligands, thus modulating immune reactions and influencing susceptibility to disease.
Leukocyte immunoglobulin-like receptor subfamily A member 2 is a protein that in humans is encoded by the LILRA2 gene.
Leukocyte-associated immunoglobulin-like receptor 2 is a protein that in humans is encoded by the LAIR2 gene.
Killer cell immunoglobulin-like receptor 3DL3 is a protein that in humans is encoded by the KIR3DL3 gene.
Killer cell immunoglobulin-like receptor, two domains, short cytoplasmic tail, 1 is a protein that in humans is encoded by the KIR2DS1 gene.
KIR2DL3, Killer cell immunoglobulin-like receptor 2DL3 is a transmembrane glycoprotein expressed by the natural killer cells and the subsets of the T cells. The KIR genes are polymorphic, which means that they have many different alleles. The KIR genes are also extremely homologous, which means that they are similar in position, structure and evolutionary origin, but not necessarily in function.
Paired receptors are pairs or clusters of receptor proteins that bind to extracellular ligands but have opposing activating and inhibitory signaling effects. Traditionally, paired receptors are defined as homologous pairs with similar extracellular domains and different cytoplasmic regions, whose genes are located together in the genome as part of the same gene cluster and which evolved through gene duplication. Homologous paired receptors often, but not always, have a shared ligand in common. More broadly, pairs of receptors have been identified that exhibit paired functional behavior - responding to a shared ligand with opposing intracellular signals - but are not closely homologous or co-located in the genome. Paired receptors are highly expressed in the cells of the immune system, especially natural killer (NK) and myeloid cells, and are involved in immune regulation.
