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HLA-DM
HLA-DM (human leukocyte antigen DM) is an intracellular protein involved in the mechanism of antigen presentation on antigen presenting cells (APCs) of the immune system. It does this by assisting in peptide loading of major histocompatibility complex (MHC) class II membrane-bound proteins. HLA-DM is encoded by the genes HLA-DMA and HLA-DMB. HLA-DM is a molecular chaperone that works in lysosomes and endosomes in cells of the immune system. It works in APCs like macrophages, dendritic cells, and B cells by interacting with MHC class II molecules. HLA-DM protects the MHC class II molecules from breaking down, and regulates which proteins or peptides bind to them as well. This regulates how and when a peptide acts as an antigen initiating an immune response. Thus, HLA-DM is necessary for the immune system to respond effectively to a foreign invader. Impairment in HLA-DM function can result in immunodeficiency and autoimmune diseases. Genetics The genes for HLA-DM are located in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DM Transport And Functions From The ER To The Cell Surface Of An APC
HLA-DM (human leukocyte antigen DM) is an intracellular protein involved in the mechanism of antigen presentation on antigen presenting cells (APCs) of the immune system. It does this by assisting in peptide loading of major histocompatibility complex (MHC) class II membrane-bound proteins. HLA-DM is encoded by the genes HLA-DMA and HLA-DMB. HLA-DM is a molecular chaperone that works in lysosomes and endosomes in cells of the immune system. It works in APCs like macrophages, dendritic cells, and B cells by interacting with MHC class II molecules. HLA-DM protects the MHC class II molecules from breaking down, and regulates which proteins or peptides bind to them as well. This regulates how and when a peptide acts as an antigen initiating an immune response. Thus, HLA-DM is necessary for the immune system to respond effectively to a foreign invader. Impairment in HLA-DM function can result in immunodeficiency and autoimmune diseases. Genetics The genes for HLA-DM are loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DO
Human leukocyte histocompatibility complex DO (HLA-DO) is an intracellular, dimeric non-classical Major Histocompatibility Complex (MHC) class II protein composed of α- and β-subunits which interact with HLA-DM in order to fine tune immunodominant epitope selection. As a non-classical MHC class II molecule, HLA-DO is a non-polymorphic accessory protein that aids in antigenic peptide chaperoning and loading, as opposed to its classical counterparts, which are polymorphic and involved in antigen presentation. Though more remains to be elucidated about the function of HLA-DO, its unique distribution in the mammalian body—namely, the exclusive expression of HLA-DO in B cells, thymic medullary epithelial cells, and dendritic cells—indicate that it may be of physiological importance and has inspired further research. Although HLA-DM can be found without HLA-DO, HLA-DO is only found in complex with HLA-DM and exhibits instability in the absence of HLA-DM. The evolutionary con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DMB
HLA class II histocompatibility antigen, DM beta chain is a protein that in humans is encoded by the ''HLA-DMB'' gene. Function HLA-DMB belongs to the HLA class II beta chain paralogues. This class II molecule is a heterodimer consisting of an alpha (DMA) and a beta (DMB) chain, both anchored in the membrane. It is located in intracellular vesicles. DM plays a central role in the peptide loading of MHC class II molecules by helping to release the CLIP (class II-associated invariant chain peptide) molecule from the peptide binding site. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The beta chain is approximately 26-28 kDa The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at re ... and its gene contains 6 exons. Exon on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HLA-DMA
HLA class II histocompatibility antigen, DM alpha chain is a protein that in humans is encoded by the ''HLA-DMA'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b .... HLA-DMA belongs to the HLA class II alpha chain paralogues. This class II molecule is a heterodimer consisting of an alpha (DMA) and a beta chain (DMB), both anchored in the membrane. It is located in intracellular vesicles. DM plays a central role in the peptide loading of MHC class II molecules by helping to release the CLIP molecule from the peptide binding site. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The alpha chain is approximately 33-35 kDa and its gene contains 5 exons. Exon one encodes the leader peptide, exons 2 and 3 encode the two e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD74
HLA class II histocompatibility antigen gamma chain also known as HLA-DR antigens-associated invariant chain or CD74 (Cluster of Differentiation 74), is a protein that in humans is encoded by the ''CD74'' gene. The invariant chain (Abbreviated Ii) is a polypeptide which plays a critical role in antigen presentation. It is involved in the formation and transport of MHC class II peptide complexes for the generation of CD4+ T cell responses. The cell surface form of the invariant chain is known as CD74. CD74 is a cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF). Function The nascent MHC class II protein in the rough endoplasmic reticulum (RER) binds a segment of the invariant chain (Ii; a trimer) in order to shape the peptide-binding groove and prevent the formation of a closed conformation. The invariant chain also facilitates the export of MHC class II from the RER in a vesicle. The signal for endosomal targeting resides in the cytoplasmic ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunoglobulin C1-set Domain
C1-set domains are classical Ig-like domains resembling the antibody constant domain. C1-set domains are found almost exclusively in molecules involved in the immune system, such as in immunoglobulin light and heavy chains, in the major histocompatibility complex (MHC) class I and II complex molecules, and in various T-cell receptors. Human proteins containing this domain AZGP1; B2M; CD1A; CD1B; CD1C; CD1D; CD1E; DMA; DQB2; DRB1; ELK2P1; FCGRT; HFE; HHLA2; HLA-A; HLA-B; HLA-B35; HLA-B57; HLA-C; HLA-CW; HLA-Cw; HLA-D; HLA-DMA; HLA-DMB; HLA-DOA; HLA-DOB; HLA-DP; HLA-DPA1; HLA-DPB1; HLA-DQA1; HLA-DQA2; HLA-DQB1; HLA-DQB2; HLA-DRA; HLA-DRB1; HLA-DRB2; HLA-DRB3; HLA-DRB4; HLA-DRw12; HLA-Dw12; HLA-E; HLA-F; HLA-G; HLA-G2.2; HLA-H; HLAC; IGHA1; IGHA2; IGHD; IGHE; IGHG1; IGHG2; IGHG3; IGHG4; IGHM; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen-presenting Cell
An antigen-presenting cell (APC) or accessory cell is a cell that displays antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation. T cells may recognize these complexes using their T cell receptors (TCRs). APCs process antigens and present them to T-cells. Almost all cell types can present antigens in some way. They are found in a variety of tissue types. Professional antigen-presenting cells, including macrophages, B cells and dendritic cells, present foreign antigens to helper T cells, while virus-infected cells (or cancer cells) can present antigens originating inside the cell to cytotoxic T cells. In addition to the MHC family of proteins, antigen presentation relies on other specialized signaling molecules on the surfaces of both APCs and T cells. Antigen-presenting cells are vital for effective adaptive immune response, as the functioning of both cytotoxic and helper T cells is dependent on APCs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallography
Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics ( condensed matter physics). The word "crystallography" is derived from the Greek word κρύσταλλος (''krystallos'') "clear ice, rock-crystal", with its meaning extending to all solids with some degree of transparency, and γράφειν (''graphein'') "to write". In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming that 2014 would be the International Year of Crystallography. denote a direction vector (in real space). * Coordinates in ''angle brackets'' or ''chevrons'' such as <100> denote a ''family'' of directions which are related by symmetry operations. In the cubic crystal system for example, would mean 00 10 01/nowiki> or the negative of any of those directions. * Miller indices in ''parentheses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-terminal
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is translated from messenger RNA, it is created from N-terminus to C-terminus. The convention for writing peptide sequences is to put the C-terminal end on the right and write the sequence from N- to C-terminus. Chemistry Each amino acid has a carboxyl group and an amine group. Amino acids link to one another to form a chain by a dehydration reaction which joins the amine group of one amino acid to the carboxyl group of the next. Thus polypeptide chains have an end with an unbound carboxyl group, the C-terminus, and an end with an unbound amine group, the N-terminus. Proteins are naturally synthesized starting from the N-terminus and ending at the C-terminus. Function C-terminal retention signals While the N-terminus of a protein often con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminal
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denaturation (biochemistry)
In biochemistry, denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation or heat. If proteins in a living cell are denatured, this results in disruption of cell activity and possibly cell death. Protein denaturation is also a consequence of cell death. Denatured proteins can exhibit a wide range of characteristics, from conformational change and loss of solubility to aggregation due to the exposure of hydrophobic groups. The loss of solubility as a result of denaturation is called ''coagulation''. Denatured proteins lose their 3D structure and therefore cannot function. Protein folding is key to whether a globular or membrane protein can do its job correctly; it mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperone (protein)
In molecular biology, molecular chaperones are proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes. There are a number of classes of molecular chaperones, all of which function to assist large proteins in proper protein folding during or after synthesis, and after partial denaturation. Chaperones are also involved in the translocation of proteins for proteolysis. The first molecular chaperones discovered were a type of assembly chaperones which assist in the assembly of nucleosomes from folded histones and DNA. One major function of molecular chaperones is to prevent the aggregation of misfolded proteins, thus many chaperone proteins are classified as heat shock proteins, as the tendency for protein aggregation is increased by heat stress. The majority of molecular chaperones do not convey any steric information for protein folding, and instead assist in protein folding by binding to and stabilizing folding intermed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
