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PTPRB
Receptor-type tyrosine-protein phosphatase beta or VE-PTP is an enzyme specifically expressed in endothelial cells that in humans is encoded by the ''PTPRB'' gene. Function VE-PTP is a member of the classical protein tyrosine phosphatase (PTP) family. The deletion of the gene in mouse models was shown to be embryonically lethal, thus indicating that it is important for vasculogenesis and blood vessel development. In addition, it was shown to participate in adherens junctions complex and regulate vascular permeability. Recently, Soni et al. have shown that tyrosine phosphorylation of VE-PTP via Pyk2 kinase downstream of STIM1-induced calcium entry mediates disassembly of the endothelial adherens junctions. Interactions VE-PTP contains an extracellular domain composed of multiple fibronectin type_III repeats, a single transmembrane segment and one intracytoplasmic catalytic domain, thus belongs to R3 receptor subtype PTPs. The extracellular region was shown to interact with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VE-cadherin
Cadherin 5, type 2 or VE-cadherin (vascular endothelial cadherin) also known as CD144 ( Cluster of Differentiation 144), is a type of cadherin. It is encoded by the human gene ''CDH5''. Function VE-cadherin is a classical cadherin from the cadherin superfamily and the gene is located in a six-cadherin cluster in a region on the long arm of chromosome 16 that is involved in loss of heterozygosity events in breast and prostate cancer. The encoded protein is a calcium-dependent cell–cell adhesion glycoprotein composed of five extracellular cadherin repeats, a transmembrane region and a highly conserved cytoplasmic tail. Functioning as a classic cadherin by imparting to cells the ability to adhere in a homophilic manner, the protein may play an important role in endothelial cell biology through control of the cohesion and organization of the intercellular junctions. Integrity of intercellular junctions is a major determinant of permeability of the endothelium, and the VE-cadheri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelial Cell
The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. Endothelial cells form the barrier between vessels and tissue and control the flow of substances and fluid into and out of a tissue. Endothelial cells in direct contact with blood are called vascular endothelial cells whereas those in direct contact with lymph are known as lymphatic endothelial cells. Vascular endothelial cells line the entire circulatory system, from the heart to the smallest capillaries. These cells have unique functions that include fluid filtration, such as in the glomerulus of the kidney, blood vessel tone, hemostasis, neutrophil recruitment, and hormone trafficking. Endothelium of the interior surfaces of the heart chambers is called endocardium. An impaired function can lead to serious health issues throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Tyrosine Phosphatase
Protein tyrosine phosphatases (EC 3.1.3.48, systematic name protein-tyrosine-phosphate phosphohydrolase) are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins: : proteintyrosine phosphate + H2O = proteintyrosine + phosphate Protein tyrosine (pTyr) phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular localization, affect protein stability, and regulate enzyme activity. As a consequence, maintaining an appropriate level of protein tyrosine phosphorylation is essential for many cellular functions. Tyrosine-specific protein phosphatases (PTPase; ) catalyse the removal of a phosphate group attached to a tyrosine residue, using a cysteinyl-phosphate enzyme intermediate. These enzymes are key regulatory components in signal transduction pathways (such as the MAP kinase pathway) and cell cycle control, and are important in the control of cell growth, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasculogenesis
Vasculogenesis is the process of blood vessel formation, occurring by a '' de novo'' production of endothelial cells. It is sometimes paired with angiogenesis, as the first stage of the formation of the vascular network, closely followed by angiogenesis. Process In the sense distinguished from angiogenesis, vasculogenesis is different in one aspect: whereas angiogenesis is the formation of new blood vessels from pre-existing ones, vasculogenesis is the formation of new blood vessels, in blood islands, when there are no pre-existing ones. For example, if a monolayer of endothelial cells begins sprouting to form capillaries, angiogenesis is occurring. Vasculogenesis, in contrast, is when endothelial precursor cells (angioblasts) migrate and differentiate in response to local cues (such as growth factors and extracellular matrices) to form new blood vessels. These vascular trees are then pruned and extended through angiogenesis. Occurrences Vasculogenesis occurs during embryologic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adherens Junctions
Adherens junctions (or zonula adherens, intermediate junction, or "belt desmosome") are protein complexes that occur at cell–cell junctions, cell–matrix junctions in epithelial and endothelial tissues, usually more basal than tight junctions. An adherens junction is defined as a cell junction whose cytoplasmic face is linked to the actin cytoskeleton. They can appear as bands encircling the cell (zonula adherens) or as spots of attachment to the extracellular matrix (focal adhesion). Adherens junctions uniquely disassemble in uterine epithelial cells to allow the blastocyst to penetrate between epithelial cells. A similar cell junction in non-epithelial, non-endothelial cells is the fascia adherens. It is structurally the same, but appears in ribbonlike patterns that do not completely encircle the cells. One example is in cardiomyocytes. Proteins Adherens junctions are composed of the following proteins: * cadherins. The cadherins are a family of transmembrane proteins tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Permeability
Vascular permeability, often in the form of capillary permeability or microvascular permeability, characterizes the capacity of a blood vessel wall to allow for the flow of small molecules (drugs, nutrients, water, ions) or even whole cells (lymphocytes on their way to the site of inflammation) in and out of the vessel. Blood vessel walls are lined by a single layer of endothelial cells. The gaps between endothelial cells (cell junctions) are strictly regulated depending on the type and physiological state of the tissue. There are several techniques to measure vascular permeability to certain molecules. For instance, the cannulation of a single microvessel with a micropipette, the microvessel is perfused with a certain pressure, occluded downstream and then the velocity of some cells will be related to the permeability.Michel, C. C., Mason, J. C., Curry, F. E. & Tooke, J. E. Development of Landis Technique for Measuring Filtration Coefficient of Individual Capillaries in Frog M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyk2
Protein tyrosine kinase 2 beta is an enzyme that in humans is encoded by the ''PTK2B'' gene. Function This gene encodes a cytoplasmic protein tyrosine kinase that is involved in calcium-induced regulation of ion channels and activation of the map kinase signaling pathway. The encoded protein may represent an important signaling intermediate between neuropeptide-activated receptors or neurotransmitters that increase calcium flux and the downstream signals that regulate neuronal activity. The encoded protein undergoes rapid tyrosine phosphorylation and activation in response to increases in the intracellular calcium concentration , nicotinic acetylcholine receptor activation, membrane depolarization, or protein kinase C activation. In addition, SOCE-induced Pyk2 activation mediates disassembly of endothelial adherens junctions, via tyrosine (Y1981-residue) phosphorylation of VE-PTP. This protein has been shown to bind a CRK-associated substrate, a nephrocystin, a GTPase re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STIM1
Stromal interaction molecule 1 is a protein that in humans is encoded by the ''STIM1'' gene. STIM1 has a single transmembrane domain, and is localized to the endoplasmic reticulum, and to a lesser extent to the plasma membrane. Even though the protein has been identified earlier, its function was unknown until recently. In 2005, it was discovered that STIM1 functions as a calcium sensor in the endoplasmic reticulum. Upon activation of the IP3 receptor, the calcium concentration in the endoplasmic reticulum decreases, which is sensed by STIM1, via its EF hand domain. STIM1 activates the "store-operated" ORAI1 calcium ion channels in the plasma membrane, via intracellular STIM1 movement, clustering under plasma membrane and protein interaction with ORAI isoforms. STIM1-mediated calcium entry is required for thrombin-induced disassembly of VE-cadherin adherens junctions. 2-Aminoethoxydiphenyl borate (2-APB) and 4-chloro-3-ethylphenol (4-CEP) cause STIM1 clustering in a cell and preven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiopoietin
Angiopoietin is part of a family of vascular growth factors that play a role in embryonic and postnatal angiogenesis. Angiopoietin signaling most directly corresponds with angiogenesis, the process by which new arteries and veins form from preexisting blood vessels. Angiogenesis proceeds through sprouting, endothelial cell migration, proliferation, and vessel destabilization and stabilization. They are responsible for assembling and disassembling the endothelial lining of blood vessels. Angiopoietin cytokines are involved with controlling microvascular permeability, vasodilation, and vasoconstriction by signaling smooth muscle cells surrounding vessels. There are now four identified angiopoietins: ANGPT1, ANGPT2, ANGPTL3, ANGPT4. In addition, there are a number of proteins that are closely related to ('like') angiopoietins (Angiopoietin-related protein 1, , , , , , , ). Angiopoietin-1 is critical for vessel maturation, adhesion, migration, and survival. Angiopoietin-2, on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tie-2
The angiopoietin receptors are receptors that bind angiopoietin. TIE-1 and TIE-2 comprise the cell-surface receptors that bind and are activated by the angiopoietins, (Ang1, Ang2, Ang3, Ang4). The angiopoietins are protein growth factors required for the formation of blood vessels (angiogenesis). Angiopoietins The angiopoietins are protein growth factors that regulate angiogenesis, the formation of blood vessels. In humans, three angiopoietins have been identified: Ang1, Ang2, and Ang4 (Ang 3 is the mouse ortholog of human Ang4). Ang1 and Ang4 function as agonistic or activating ligands for Tie2, whereas Ang2 and Ang3 behave as competitive antagonists. They function by binding their physiologic receptors, Tie-1 and Tie-2. These are receptor tyrosine kinases, so named because they mediate cell signals by inducing the phosphorylation of key tyrosines, thus initiating cell signalling In biology, cell signaling (cell signalling in British English) or cell communication is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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