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Co-receptor
A co-receptor is a cell surface receptor that binds a signalling molecule in addition to a primary receptor in order to facilitate Ligand (biochemistry), ligand recognition and initiate biological processes, such as entry of a pathogen into a host cell. Properties The term co-receptor is prominent in literature regarding signal transduction, the process by which external stimuli regulate internal cellular functioning.Gomperts, BD.; Kramer, IM. Tatham, PER. (2002). Signal transduction. Academic Press. ISBN. The key to optimal cellular functioning is maintained by possessing specific machinery that can carry out tasks efficiently and effectively. Specifically, the process through which intermolecular reactions forward and amplify extracellular signals across the cell surface has developed to occur by two mechanisms. First, cell surface receptors can directly transduce signals by possessing both serine and threonine or simply serine in the cytoplasmic domain. They can also transmit s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCR5
C-C chemokine receptor type 5, also known as CCR5 or CD195, is a protein on the surface of white blood cells that is involved in the immune system as it acts as a receptor for chemokines. In humans, the ''CCR5'' gene that encodes the CCR5 protein is located on the short (p) arm at position 21 on chromosome 3. Certain populations have inherited the ''Delta 32'' mutation, resulting in the genetic deletion of a portion of the CCR5 gene. Homozygous carriers of this mutation are resistant to infection by macrophage-tropic (M-tropic) strains of HIV-1. Tissue distribution CCR5 is predominantly expressed on T cells, macrophages, dendritic cells, eosinophils, microglia and a subpopulation of either breast or prostate cancer cells. The expression of CCR5 is selectively induced during the cancer transformation process and is not expressed in normal breast or prostate epithelial cells. Approximately 50% of human breast cancer expressed CCR5, primarily in triple negative brea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cell Receptor
The T-cell receptor (TCR) is a protein complex, located on the surface of T cells (also called T lymphocytes). They are responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. The binding between TCR and antigen peptides is of relatively low affinity and is biologically degenerate (that is, many TCRs recognize the same antigen peptide, and many antigen peptides are recognized by the same TCR). The TCR is composed of two different protein chains (that is, it is a hetero dimer). In humans, in 95% of T cells the TCR consists of an alpha (α) chain and a beta (β) chain (encoded by ''TRA'' and ''TRB'', respectively), whereas in 5% of T cells the TCR consists of gamma and delta (γ/δ) chains (encoded by '' TRG'' and '' TRD'', respectively). This ratio changes during ontogeny and in diseased states (such as leukemia). It also differs between species. Orthologues of the 4 loci have been mapped in various species. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCR3 (gene)
C-C chemokine receptor type 3 is a protein that in humans is encoded by the ''CCR3'' gene. CCR3 has also recently been designated CD193 ( cluster of differentiation 193). Function The protein encoded by this gene is a receptor for C-C type chemokines. It belongs to family 1 of the G protein-coupled receptors. This receptor binds and responds to a variety of chemokines, including eotaxin ( CCL11), eotaxin-3 ( CCL26), MCP-3 ( CCL7), MCP-4 ( CCL13), and RANTES ( CCL5). It is highly expressed in eosinophils and basophils, and is also detected in TH1 and TH2 cells, as well as in airway epithelial cells. This receptor may contribute to the accumulation and activation of eosinophils and other inflammatory cells in the allergic airway, and possibly at sites of parasitic infection. It is also known to be an entry co-receptor for HIV-1, enabling viral infection in cells that also express CD4 In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Endothelial Growth Factors
Vascular endothelial growth factor (VEGF, ), originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors, the platelet-derived growth factor family of cystine-knot growth factors. They are important signaling proteins involved in both vasculogenesis (the '' de novo'' formation of the embryonic circulatory system) and angiogenesis (the growth of blood vessels from pre-existing vasculature). It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate such as in hypoxic conditions. Serum concentration of VEGF is high in bronchial asthma and diabetes mellitus. VEGF's normal function is to create new blood vessels during embryonic development, new blood vessels after injury, muscle following exercise, and new vessels (collateral circulation) to bypass blocked vessels. It can contribute to disease. So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CXCR4
C-X-C chemokine receptor type 4 (CXCR-4) also known as fusin or CD184 (cluster of differentiation 184) is a protein that in humans is encoded by the ''CXCR4'' gene. The protein is a CXC chemokine receptor. Function CXCR-4 is an alpha- chemokine receptor specific for stromal-derived-factor-1 ( SDF-1 also called CXCL12), a molecule endowed with potent chemotactic activity for lymphocytes. CXCR4 is one of several chemokine co-receptors that HIV can use to infect CD4+ T cells. HIV isolates that use CXCR4 are traditionally known as T-cell tropic isolates. Typically, these viruses are found late in infection. It is unclear as to whether the emergence of CXCR4-using HIV is a consequence or a cause of immunodeficiency. CXCR4 is upregulated during the implantation window in natural and hormone replacement therapy cycles in the endometrium, producing, in presence of a human blastocyst, a surface polarization of the CXCR4 receptors suggesting that this receptor is implicated in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-cells
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface receptor, cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: Cytotoxic T cell, CD8+ "killer" (cytotoxic) and T helper cell, CD4+ "helper" T cells. (These are named for the presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotrophic Factors
Neurotrophic factors (NTFs) are a family of biomolecules – nearly all of which are peptides or small proteins – that support the growth, survival, and cell differentiation, differentiation of both developing and mature neurons. Most NTFs exert their trophic effects on neurons by signaling through tyrosine kinases, usually a receptor tyrosine kinase. In the mature nervous system, they promote neuronal survival, induce synaptic plasticity, and modulate the formation of long-term memories. Neurotrophic factors also promote the initial growth and development of neurons in the central nervous system and peripheral nervous system, and they are capable of regrowing damaged neurons in test tubes and animal models. Some neurotrophic factors are also released by the target tissue in order to axon guidance, guide the growth of developing axons. Most neurotrophic factors belong to one of three families: (1) neurotrophins, (2) glial cell-line derived neurotrophic factor family liga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast Growth Factors
Fibroblast growth factors (FGF) are a family of cell signalling proteins produced by the macrophages. They are involved in a wide variety of processes, most notably as crucial elements for normal development in animal cells. Any irregularities in their function will lead to a range of developmental defects. These growth factors typically act as a systemic or locally circulating molecules of extracellular origin that activate cell surface receptors. A defining property of FGFs is that they bind to heparin and to heparan sulfate. Thus, some are sequestered in the extracellular matrix of tissues that contains heparan sulfate proteoglycans, and released locally upon injury or tissue remodeling. Families In humans, 23 members of the FGF family have been identified, all of which are ''structurally'' related signaling molecules: * Members FGF1 through FGF10 all bind fibroblast growth factor receptors (FGFRs). FGF1 is also known as ''acidic fibroblast growth factor'', and FGF2 is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Envelope Glycoprotein GP120
Envelope glycoprotein GP120 (or gp120) is a glycoprotein exposed on the surface of the HIV envelope. It was discovered by Professors Tun-Hou Lee and Myron "Max" Essex of the Harvard School of Public Health in 1984. The 120 in its name comes from its molecular weight of 120 kDa. Gp120 is essential for virus entry into cells as it plays a vital role in attachment to specific cell surface receptors. These receptors are DC-SIGN, Heparan Sulfate Proteoglycan and a specific interaction with the CD4 receptor, particularly on helper T-cells. Binding to CD4 induces the start of a cascade of conformational changes in gp120 and gp41 that lead to the fusion of the viral membrane with the host cell membrane. Binding to CD4 is mainly electrostatic although there are van der Waals interactions and hydrogen bonds. Gp120 is coded by the HIV ''env'' gene, which is around 2.5 kb long and codes for around 850 amino acids.Kuiken, C., Leitner, T., Foley, B., ''et al.'' (2008)"HIV Sequence Compe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form. By type: * natural vs synthetic, e.g. glycine vs caprolactam, respectively * polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively * cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively By type of polymer they form: * those that participate in condensation polymerization * those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer. : The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Dimer
In biochemistry, a protein dimer is a macromolecular complex or protein multimer, multimer formed by two protein monomers, or single proteins, which are usually Non-covalent interaction, non-covalently bound. Many macromolecules, such as proteins or nucleic acids, form dimers. The word ''dimer'' has roots meaning "two parts", ''wikt:di-#Prefix, di-'' + ''wikt:-mer#Suffix, -mer''. A protein dimer is a type of protein quaternary structure. A protein homodimer is formed by two identical proteins while a protein heterodimer is formed by two different proteins. Most protein dimers in biochemistry are not connected by covalent bonds. An example of a non-covalent heterodimer is the enzyme reverse transcriptase, which is composed of two different amino acid chains. An exception is dimers that are linked by disulfide bridges such as the homodimeric protein IKBKG, NEMO. Some proteins contain specialized domains to ensure dimerization (dimerization domains) and specificity. The G protein- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
