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ULBP1
UL16 binding protein 1 (ULBP1) is a cell surface glycoprotein encoded by ''ULBP1'' gene located on the chromosome 6. ULBP1 is related to MHC class I molecules, but its gene maps outside the MHC locus. The domain structure of ULBP1 differs significantly from those of conventional MHC class I molecules. It does not contain the α3 domain and the transmembrane segment. ULBP1 is thus composed of only the α1α2 domain which is linked to the cell membrane by the GPI anchor. It functions as a stress-induced ligand for NKG2D receptor. ULBP1 is, for example, upregulated during HCMV ''Human betaherpesvirus 5'', also called human cytomegalovirus (HCMV), is species of virus in the genus ''Cytomegalovirus'', which in turn is a member of the viral family known as ''Herpesviridae'' or herpesviruses. It is also commonly called ... infection. Binding of HCMV-encoded UL16 glycoprotein to ULBP1 interferes with cell surface localization of ULBP1; this represents another mechanism by which HCMV- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NKG2D
NKG2D is an activating receptor (transmembrane protein) belonging to the NKG2 family of C-type lectin, C-type lectin-like receptors. NKG2D is encoded by ''KLRK1'' (killer cell lectin like receptor K1) gene which is located in the NK-gene complex (NKC) situated on chromosome 6 in mice and chromosome 12 in humans. In mice, it is expressed by Natural killer cell, NK cells, Natural killer T cell, NK1.1+ T cells, Gamma delta T cell, γδ T cells, activated Cytotoxic T cell, CD8+ αβ T cells and activated macrophages. In humans, it is expressed by Natural killer cell, NK cells, Gamma delta T cell, γδ T cells and Cytotoxic T cell, CD8+ αβ T cells. NKG2D recognizes Induced-self antigen, induced-self proteins from MIC and RAET1/ULBP families which appear on the surface of stressed, malignant transformed, and infected cells. Structure Human NKG2D receptor complex assembles into a hexameric structure. NKG2D itself forms a homodimer whose ectodomains serve for ligand binding. Each NKG ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Induced-self Antigen
Induced-self antigen is a marker of abnormal self, which can be recognized upon infected (in particular, virus-infected) and transformed cells. Therefore, the recognition of "induced self" is an important strategy for surveillance of infection or tumor transformation - it results in elimination of the affected cells by activated NK cells or other immunological mechanisms. Similarly γδ T cells can recognize induced-self antigens expressed on cells under stress conditions. Receptors Probably the most studied receptor involved in recognition of induced-self antigens is NKG2D NKG2D is an activating receptor (transmembrane protein) belonging to the NKG2 family of C-type lectin-like receptors. NKG2D is encoded by ''KLRK1'' (killer cell lectin like receptor K1) gene which is located in the NK-gene complex (NKC) situated .... It is an activating receptor which is expressed on NK cells and subsets of T and NKT cells. NKG2D can bind proteins at the surface of most cells that are not nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycoprotein
Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated. In proteins that have segments extending extracellularly, the extracellular segments are also often glycosylated. Glycoproteins are also often important integral membrane proteins, where they play a role in cell–cell interactions. It is important to distinguish endoplasmic reticulum-based glycosylation of the secretory system from reversible cytosolic-nuclear glycosylation. Glycoproteins of the cytosol and nucleus can be modified through the reversible addition of a single GlcNAc residue that is considered reciprocal to phosphorylation and the functions of these are likely to be an additional regulatory mechanism that controls phosphorylation-based signalling. In contrast, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MHC Class I
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates. They also occur on platelets, but not on red blood cells. Their function is to display peptide fragments of proteins from within the cell to cytotoxic T cells; this will trigger an immediate response from the immune system against a particular non-self antigen displayed with the help of an MHC class I protein. Because MHC class I molecules present peptides derived from cytosolic proteins, the pathway of MHC class I presentation is often called ''cytosolic'' or ''endogenous pathway''. In humans, the HLAs corresponding to MHC class I are HLA-A, HLA-B, and HLA-C. Function Class I MHC molecules bind peptides generated mainly from degradation of cytosolic proteins by the proteasome. The MHC I:peptide complex is then inserted via endoplasmic reticulum into the ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycophosphatidylinositol
Glycosylphosphatidylinositol (), or glycophosphatidylinositol, or GPI in short, is a phosphoglyceride that can be attached to the C-terminus of a protein during posttranslational modification. The resulting GPI-anchored proteins play key roles in a wide variety of biological processes. GPI is composed of a phosphatidylinositol group linked through a carbohydrate-containing linker (glucosamine and mannose glycosidically bound to the inositol residue) and via an ethanolamine phosphate (EtNP) bridge to the C-terminal amino acid of a mature protein. The two fatty acids within the hydrophobic phosphatidyl-inositol group anchor the protein to the cell membrane. Synthesis Glycosylated (GPI-anchored) proteins contain a signal sequence, thus directing them to the endoplasmic reticulum (ER). The protein is co-translationally inserted in the ER membrane via a translocon and is attached to the ER membrane by its hydrophobic C terminus; the majority of the protein extends into the ER lumen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
