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PIK3C2A
Phosphatidylinositol-4-phosphate 3-kinase C2 domain-containing alpha polypeptide is an enzyme that in humans is encoded by the ''PIK3C2A'' gene. The protein encoded by this gene belongs to the phosphoinositide 3-kinase (PI3K) family. PI3-kinases play roles in signaling pathways involved in cell proliferation, oncogenic transformation, cell survival, cell migration, and intracellular protein trafficking. This protein contains a lipid kinase catalytic domain as well as a C-terminal C2 domain, a characteristic of Class II PI 3-kinases. C2 domains act as calcium-dependent phospholipid binding motifs that mediate translocation of proteins to membranes, and may also mediate protein-protein interactions. The PI3-kinase activity of this protein is not sensitive to nanomolar levels of the inhibitor wortmannin. This protein was shown to be able to be activated by insulin and may be involved in integrin-dependent signaling. Clinical significance Three families have been reported with homoz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C2 Domain
A C2 domain is a protein structural domain involved in targeting proteins to cell membranes. The typical version (PKC-C2) has a beta-sandwich composed of 8 beta sheet, β-strands that co-ordinates two or three calcium ions, which bind in a cavity formed by the first and final loops of the domain, on the membrane binding face. Many other C2 domain families don't have calcium binding activity. Coupling with other domains C2 domains are frequently found coupled to enzyme, enzymatic domains; for example, the C2 domain in PTEN (gene), PTEN, brings the phosphatase domain into contact with the plasma membrane, where it can dephosphorylate its substrate, Phosphatidylinositol (3,4,5)-trisphosphate, phosphatidylinositol (3,4,5)-trisphosphate (PIP3), without removing it from the membrane - which would be energetically very costly. PTEN consists of two domains, a protein tyrosine phosphatase domain and a C2 domain. This domain pair constitutes a superdomain, a heritable unit that is found in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PI3K
Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which in turn are involved in cancer. PI3Ks are a family of related intracellular signal transducer enzymes capable of phosphorylating the 3 position hydroxyl group of the inositol ring of phosphatidylinositol (PtdIns). The pathway, with oncogene PIK3CA and tumor suppressor gene PTEN, is implicated in the sensitivity of cancer tumors to insulin and IGF1, and in calorie restriction. Discovery The discovery of PI3Ks by Lewis Cantley and colleagues began with their identification of a previously unknown phosphoinositide kinase associated with the polyoma middle T protein. They observed unique substrate specificity and chromatographic properties of the products of the lipid kinase, leading to the discovery that this phosphoinositide kinase had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class II PI 3-kinases
Class II PI 3-kinases are a subgroup of the enzyme family, phosphoinositide 3-kinase that share a common protein domain structure, substrate specificity and method of activation. Class II PI 3-kinases were the most recently identified class of PI 3-kinases. There are three class II PI 3-kinase isoforms expressed in mammalian cells; *PI3K-C2α encoded by the PIK3C2A gene *PI3K-C2β encoded by the PIK3C2B gene *PI3K-C2γ encoded by the PIK3C2G gene See also * Phosphoinositide 3-kinase Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which i ... References *Stein RC (2001) Prospects for phosphoinositide 3-kinase inhibition as a cancer treatment ''Endocr Relat Cancer'' 8:237-24*Foster FM, Traer CJ, Abraham SM, and Fry MJ (2003) The phosphoinositide (PI) 3-kinase family ''J Cell Sci'' 116:3037-3 ... [...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] |
Insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of glucose from the blood into liver, fat and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both. Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells. Low insulin levels in the blood have the opposite effect by promoting widespread catabolism, especially o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Glaucoma
Secondary glaucoma is a collection of progressive optic nerve disorders associated with a rise in intraocular pressure (IOP) which results in the loss of vision. In clinical settings, it is defined as the occurrence of IOP above 21 mmHg requiring the prescription of IOP-managing drugs. It can be broadly divided into two subtypes: secondary open-angle glaucoma and secondary angle-closure glaucoma, depending on the closure of the Anterior chamber angle, angle between the cornea and the Iris (anatomy), iris. Principal causes of secondary glaucoma include optic nerve trauma or damage, eye disease, surgery, neovascularization, tumours and use of steroid and sulfa drugs. Risk factors for secondary glaucoma include uveitis, cataract surgery and also intraocular tumours. Common treatments are designed according to the type (open-angle or angle-closure) and the underlying causative condition, in addition to the consequent rise in IOP. These include drug therapy, the use of miotics, surgery or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cataract
A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and trouble seeing at night. This may result in trouble driving, reading, or recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression. Cataracts cause 51% of all cases of blindness and 33% of visual impairment worldwide. Cataracts are most commonly due to aging but may also occur due to trauma or radiation exposure, be present from birth, or occur following eye surgery for other problems. Risk factors include diabetes, longstanding use of corticosteroid medication, smoking tobacco, prolonged exposure to sunlight, and alcohol. The underlying mechanism involves accumulation of clumps of protein or yellow-brown pigment in the lens that reduces transmission of li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. The presence of integrins allows rapid and flexible responses to events at the cell surface (''e.g''. signal platelets to initiate an interaction with coagulation factors). Several types of integrins exist, and one cell generally has multiple different types on its surface. Integrins are found in all animals while integrin-like receptors are found in plant cells. Integrins work alongside other proteins such as cadherins, the immunoglobulin superfamily cell adhesion molecules, selectins and syndecans, to mediate cell–cell and cell–matrix interaction. Ligands for integrins include fibronectin, vitronectin, collagen and laminin. Stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipid
Phospholipids, are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science. The first phospholipid identified in 1847 as such in biological tissues was lecith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wortmannin
Wortmannin, a steroid metabolite of the fungi ''Penicillium funiculosum'', '' Talaromyces wortmannii'', is a non-specific, covalent inhibitor of phosphoinositide 3-kinases (PI3Ks). It has an ''in vitro'' inhibitory concentration (''IC''50) of around 5 nM, making it a more potent inhibitor than LY294002, another commonly used PI3K inhibitor. It displays a similar potency ''in vitro'' for the class I, II, and III PI3K members although it can also inhibit other PI3K-related enzymes such as mTOR, DNA-PKcs, some phosphatidylinositol 4-kinases, myosin light chain kinase (MLCK) and mitogen-activated protein kinase (MAPK) at high concentrations Wortmannin has also been reported to inhibit members of the polo-like kinase family with ''IC''50 in the same range as for PI3K. The half-life of wortmannin in tissue culture is about 10 minutes due to the presence of the highly reactive C20 carbon that is also responsible for its ability to covalently inactivate PI3K. Wortmannin is a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanomolar
Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution. In chemistry, the most commonly used unit for molarity is the number of moles per liter, having the unit symbol mol/L or mol/ dm3 in SI unit. A solution with a concentration of 1 mol/L is said to be 1 molar, commonly designated as 1 M. Definition Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. For use in broader applications, it is defined as amount of substance of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase c: :c = \frac = \frac = \frac. Here, n is the amount of the solute in moles, N is the number of constituent particles present in volume V (in litres) of the solution, and N_\text is the Avo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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