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. Natural killer cells are an important component of innate antiviral immune response. Have the ability to lyse target cells without prior sensitization antigen and regulate the immune responses by secreting chemokine adaptive and cytokines. Activation of NK cells is determined by integration of inhibitory signals and activating issued by several families of different receptors, including immunoglobulin-like killer cell receptors that predominantly recognize antigens of class I human leukocyte antigen.
Structure and location
The genes responsible for coding of KIR proteins are found along the 19th chromosome section 19q 13.4 within the 1Mb Leukocyte Receptor Complex. The subsets of the KIR proteins are classified by their number of extracellular IG domains and by whether they have a long or short cytoplasmic domain-tail. The number coming at the end of the name of protein classifies it as a branch of the subset it belongs to.
Function
KIR proteins with long tailed cytoplasmic domains transduce the inhibitory signals upon the ligand binding via an immune tyrosine-based inhibitory motif, whereas the KIR proteins of short-tailed cytoplasmic domain lack the ITIM and instead associate with Tyrosine kinasebinding protein to transduce activating signals. The ligands for several KIR proteins are subsets of HLA class I molecules. The KIR proteins are thought to play an important role in regulating of the immune responses. The HLA molecules are human leukocyte antigens and are the gene complexes to encode Major Histocompatibility Complex proteins in human beings. Plays a great role in regulating the immune response. HLA are polymorphic, thus the MHCs of humans differ from an individual to another. KIR2DL3 is a protein complex of two extracellular domains and a long tailed endo-cellular cytoplasmatic tail, which assign it in charge of sending inhbitory signals throughout the cell.
Pathology
The protein KIR2DL3 transduces inhibitory signals upon the ligand binding via an immune tyrosine-based inhibitory motif to its long inner cytoplasmic tail. The tyrosine kinase based transductions are enzymatic transferences of a phosphate group from an ATP molecule to a protein in the cell. Thus functioning as an ' on ' and ' off ' switch in many cellular functions. Tyrosine Kinases are a sub-class of the protein-kinase. Phosphorylation of proteins is a necessary step in transduction of signals withina cell in order to regulate the cellular activity. Protein Kinases might get stuck in ' off ' position and inhibit the cell reproduction for good, or on the contrary might get stuck in ' on 'position, thus rendering the cell to reproduce unregulatedly, which is a necessary step for the development of cancer.
