NationMaster - Encyclopedia: T cell receptor

The T cell receptor or TCR is a molecule found on the surface of T lymphocytes (or T cells) that is responsible for recognizing antigens bound to major histocompatibility complex (MHC) molecules. Look up Hugo in Wiktionary, the free dictionary. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... Look up Hugo in Wiktionary, the free dictionary. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... Image File history File links Antigen_presentation. ... Image File history File links Antigen_presentation. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... This article does not cite any references or sources. ... MHC I (1hsa) vs MHC II (1dlh) (more details. ...

It is a heterodimer consisting of an alpha and beta chain in 95% of T cells, while 5% of T cells have TCRs consisting of gamma and delta chains. Sucrose, or common table sugar, is composed of glucose and fructose. ... Î³Î´ T cells represent a small subset of T cells that possess a distinct T cell receptor (TCR) on their surface. ...

Engagement of the TCR with antigen and MHC results in activation of its T lymphocyte through a series of biochemical events mediated by associated enzymes, co-receptors and specialized accessory molecules.

Structural characteristics of the TCR

Each chain of the TCR is a member of the immunoglobulin superfamily and possesses one N-terminal immunoglobulin (Ig)-variable (V) domain, one Ig-constant (C) domain, a transmembrane/cell membrane-spanning region and a short cytoplasmic tail at the C-terminal end. Cell Adhesion Molecules (CAMs) are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix (ECM) in the process called cell adhesion. ...

The variable domain of both the TCR α-chain and β-chain have three hypervariable or complementarity determining regions (CDRs), while the variable region of the β-chain has an additional area of hypervariability(HV4) that does not normally contact antigen and therefore is not considered a CDR. A single chain antibody fragment showing the positions of the three complementarity determining regions, CDR1, CDR2 and CDR3 A complementarity determining region (CDR) is a short amino acid sequence found in the variable domains of antigen receptor (e. ...

CDR3 is the main CDR responsible for recognizing processed antigen, although CDR1 of the alpha chain has also been shown to interact with the N-terminal part of the antigenic peptide while CDR1 of the beta chain interacts with the C-terminal part of the peptide. Two methods exist for an antigen to be processed and presented on the cell surface. ... The N-terminal end refers to the extremity of a protein or polypeptide terminated by an amino acid with a free amine group (NH2). ... The C-terminal end refers to the extremity of a protein or polypeptide terminated by an amino acid with a free carboxyl group (COOH). ...

CDR2 is thought to recognize the MHC. CDR4 of the β-chain is not thought to participate in antigen recognition, but has been shown to interact with superantigens. Superantigens (SAgs) are a group of virulent toxins that indiscriminately activate T-cells of the immune system causing system-wide inflammation and other serious, potentially fatal symptoms. ...

The constant domain of the TCR domain consists of short connecting sequences in which a cysteine residue forms disulfide bonds which forms a lin between the two chains.

Generation of the TCR

Processes for TCR formation are similar to those described for B-cell antigen receptors, otherwise known as immunoglobulins. The abbreviation B comes from bursa of Fabricius that is an organ in birds in which avian B cells mature. ... Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ...

The intersection of these specific regions (V and J for the alpha or gamma chain, V D and J for the beta or delta chain p3n15) corresponds to the CDR3 region that is important for antigen-MHC recognition (see above). V(D)J recombination is a mechanism of DNA recombination used by humans and other vertebrates for immunological protection against attacks by bacterial, viral, and parasitic invaders. ...

Furthermore, it is the unique combination of the segments at this region, along with palindromic and random nucleotide additions, which accounts for the great diversity in specificity of the T cell receptor for processed antigen. A palindrome is a word, phrase, number or any other sequence of units (like a strand of DNA) which has the property of reading the same in either direction (the adjustment of spaces between letters is generally permitted). ...

The TCR complex

The transmembrane region of the TCR is composed of positively charged amino acids. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In immunology, the CD3 antigen (CD stands for cluster of differentiation) is a protein complex composed of three distinct chains (CD3Î³, CD3Î´ and CD3Îµ) in mammals, that associate with molecules known as the T cell receptor (TCR) and the Î¶-chain to generate an activation signal in T lymphocytes. ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ...

It is thought that this allows the TCR to associate with other molecules like CD3, that possess three distinct chains (γ, δ and ε) in mammals and the ζ-chain. In immunology, the CD3 antigen (CD stands for cluster of differentiation) is a protein complex composed of three distinct chains (CD3Î³, CD3Î´ and CD3Îµ) in mammals, that associate with molecules known as the T cell receptor (TCR) and the Î¶-chain to generate an activation signal in T lymphocytes. ...

These accessory molecules have negatively charged transmembrane regions and are vital to propagating the signal from the TCR into the cell; the cytoplasmic tail of the TCR is extremely short, making it unlikely to participate in signaling. A transmembrane protein is a protein that spans the entire biological membrane. ... Cytoplasm is the viscid, semi-fluid matter contained within the plasma membrane of a cell that helps to hold the cell together. ...

The CD3- and ζ-chains, together with the TCR, form what is known as the T cell receptor complex.

TCR co-receptors

The signal from the T cell complex is enhanced by simultaneous binding of the MHC molecules by a specific co-receptor. This page is a candidate to be copied to Wiktionary. ...

The co-receptor not only ensures the specificity of the TCR for the correctly presented antigen, it also allows prolonged engagement between the antigen presenting cell and the T cell and recruits essential molecules (e.g. LCK) inside the cell that are involved in the signaling of that activated T lymphocyte. A T helpered cell (or TH) cell, is a T cell (a type of white blood cell or leukocyte) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class II MHC molecules found on professional antigen-presenting cells (APCs). ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates containing many genes with important immune system roles. ... A cytotoxic (or TC) T cell is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class I MHC molecules of virus (or other intracellular pathogen) infected somatic cells and tumor cells. ... CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ... It has been suggested that this article or section be merged into Major histocompatibility complex. ... An antigen presenting cell (APC) is a cell that displays foreign antigen complexed with MHC on its surface. ... Rickenbacker International Airport (airport code: LCK) is located in Columbus, Ohio. ...

References

External links

A peripheral protein from the OPM database (P40phox PX domain of of NADPH oxidase). ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ...

See also

Categories: Cell signaling | T cells | Integral membrane proteins T cells are a subset of lymphocytes that play a large role in the immune response. ... During the activation of T cells, co-stimulation of molecules is often crucial to the development of an effective immune response. ... Transmembrane receptors are integral membrane proteins, which reside and operate typically within a cells plasma membrane, but also in the membranes of some subcellular compartments and organelles. ... A immune receptor (or immunologic receptor) is a receptor, usually on a cell membrane, which binds to a substance (for example, a cytokine) and causes a response in the immune system. ... Key steps of the JAK-STAT pathway A Cytokine receptor is a receptor which binds cytokines. ... Type I cytokine receptors are proteins expressed on the surface of cells that recognize and respond to cytokines with four Î±-helical strands. ... The Interleukin-2 Receptor (IL-2R) is heterotrimeric protein expressed on the surface of certain immune cells, such as lymphocytes, that binds and responds to a cytokine called interleukin 2. ... The interleukin-3 receptor (also known as CD123 antigen) is a molecule found on cells which helps transmit the signal of interleukin-3, a soluble cytokine important in the immune system. ... Type II cytokine receptors are transmembrane proteins that are expressed on the surface of certain cells, which bind and respond to a select group of cytokines. ... Glycoprotein 130 (also known as gp130, IL6ST or CD130) is a transmembrane protein which is the founding member of the class of tall cytokine receptors. ... Typical structure of a chemokine receptor, with seven transmembrane domains and a characteristic DRY motif in the second intracellular domain. ... TGF-beta receptors bind TGF beta via two mechanisms, thus transducing a signal via one of two methods: the SMAD pathway, or the DAXX pathway: MeSH TGF-beta+Receptors Transmembrane receptors: immune receptors Antigen receptor (B-cell receptor, T cell receptor) - Complement - Fc (FcÎµRI, FcÎµRII, FcÎ³RI, Fc... A tumor necrosis factor receptor (TNFR) is, as its name would indicate, a receptor which binds tumor necrosis factors (TNF). ... IFNAR is a receptor which binds Interferon type I. MeSH Receptor,+Interferon+alpha-beta Categories: | | ... IFNGR is a receptor which binds interferon-Î³, the sole member of interferon type II. The human interferon-gamma receptor complex consists the heterodimer of two chains: IFNGR1 and IFNGR2[1][2]. In unstimulated cells, these subunits are not preassociated with each other but rather associate through their intracellular domains with... Oncostatin M receptor is a receptor for oncostatin M. MeSH Oncostatin+M+Receptor Categories: | | ... The erythropoietin receptor is a 66 kda peptide and is a member of the cytokine receptor family. ... The granulocyte macrophage colony-stimulating factor receptor is a receptor for granulocyte macrophage colony-stimulating factor. ... The granulocyte colony-stimulating factor receptor, abbreviated G-CSF-R is a cell-surface receptor for the granulocyte colony-stimulating factor (G-CSF). ... LIFR is a subunit of a receptor for leukemia inhibitory factor. ... CSF2RB is a common subunit to type I cytokine receptors. ... Pattern recognition receptors, or PRRs, are a class of cell surface receptors which are employed by the cells of the immune system to identify foreign (disease-associated) biomolecules in the body. ... Toll-like receptors (TLRs) are type I transmembrane proteins that serve as a key part of the innate immune system. ... TLR 1 is a member of the Toll-like receptor family of pattern recognition receptors of the innate immune system. ... TLR-2 is the name for a biomolecule, which plays a role in the human immune system. ... TLR 3 is one of 11 Toll-like receptors part of the innate immune system. ... TLR 4 is a toll-like receptor. ... TLR 5 is a toll-like receptor. ... TLR 6 is a toll-like receptor. ... TLR 7 is a toll-like receptor. ... TLR 8 is a toll-like receptor. ... TLR 9 is a toll-like receptor. ... TLR 10 is a toll-like receptor. ... // Fc-receptor(s) Introduction Fc-receptor(s) are structures on the surface of cells and can contribute to the protective functions of the immune system. ... FcÎµRI, or Fc epsilon RI, is the high-affinity receptor for immunoglobulin E (IgE), an antibody isotype involved in allergy and (arguably) resistance to parasites. ... CD23 or Fc epsilon RII is the low affinty receptor for IgE, an antibody isotype involved in allergy and (arguably) resistance to parasites and is important in regulation of IgE levels. ... CD64 is a Fc receptor. ... The CD32 in action The AmigaCD32 was the worlds first 32bit CD_ROM based game console. ... CD16 is a Fc receptor. ... CD89 is a Fc receptor. ... FcÎ±/Î¼R is a Fc receptor. ... The neonatal Fc receptor is a Fc receptor which is similar in structure to MHC Class I. MeSH neonatal+Fc+receptor Transmembrane receptors: immune receptors Antigen receptor (B-cell receptor, T cell receptor) - Complement - Fc (FcÎµRI, FcÎµRII, FcÎ³RI, FcÎ³RII, FcÎ³RIII, FcÎ±RI, FcÎ±/Î¼R, Neonatal... Lymphocyte homing receptors are cell adhesion molecules which target addressins. ... The CD44 protein is a cell-surface glycoprotein involved in cell-cell interactions, cell adhesion and migration. ... L-selectin (CD62L) is a cell adhesion molecule found on leukocytes; more precisely, it is a selectin, a molecule specific for carbohydrate groups. ... Integrin alpha4beta1 (Very Late Antigen-4) is an integrin dimer. ... LFA-1 stands for Lymphocyte function-associated antigen-1. ... This article or section is in need of attention from an expert on the subject. ... A Complement receptor is a receptor of the complement system, a part of the mediated innate immune system. ... A formyl peptide receptor is a member of a class of G protein-coupled receptors involved in chemotaxis. ... It has been suggested that this article or section be merged into Immunophilin. ... An integrin, or integrin receptor, is an integral membrane protein in the plasma membrane of cells. ... Killer-cell immunoglobulin-like receptors (KIRs), are a family of cell surface proteins found on important cells of the immune system called natural killer (NK) cells. ... This does not cite any references or sources. ... The T-cell receptor complex with TCR-Î± and TCR-Î² chains, CD3 and Î¶-chain accessory molecules and the co-receptor CD4 In immunology, the CD3 antigen (CD stands for cluster of differentiation) is a protein complex composed of four distinct chains (CD3Î³, CD3Î´ and two times CD3Îµ) in mammals, that associate... CD3 or CD-3 may be: CD3 receptor Ford CD3 platform MediaMax CD-3, copy protection scheme MiniCD, a 3-inch CD CD3, Color Developing Agent 3, the color developer for E6 process Category: ... CD8 (cluster of differentiation 8) is a molecule that is expressed on the surface of cytotoxic T cells. ... CD8 (cluster of differentiation 8) is a transmembrane glycoprotein which serves as a co-receptor for the T cell receptor (TCR). ... CD8 (cluster of differentiation 8) is a transmembrane glycoprotein which serves as a co-receptor for the T cell receptor (TCR). ... CD4 (cluster of differentiation 4) is a molecule that is expressed on the surface of T helper cells (as well as regulatory T cells and dendritic cells). ... MHC I (1hsa) vs MHC II (1dlh) (more details. ... MHC class I molecules are cell surface proteins found on most cells of the body. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates. ...

Contents

Structural characteristics of the TCR GA_googleFillSlot("encyclopedia_square");