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Phosphatidylinositol-3-phosphate
Phosphatidylinositol 3-phosphate (PtdIns3''P'') is a phospholipid found in cell membranes that helps to recruit a range of proteins, many of which are involved in protein trafficking, to the membranes. It is the product of both the class II and III phosphoinositide 3-kinases (PI 3-kinases) activity on phosphatidylinositol. PtdIns3''P'' is dephosphorylated by the myotubularin family of phosphatases, on the D3 position of the inositol ring, and can be converted to PtdIns(3,5)''P''2 by the lipid kinase PIKfyve. Both FYVE domains and PX domains – found in proteins such as SNX1, HGS, and EEA1 – bind to PtdIns3''P''. The majority of PtdIns3''P'' appears to be constitutively synthesised by the class III PI 3-kinase, PIK3C3 (Vps34), at endocytic membranes. 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-k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylinositol 3-phosphate-binding Protein 2
Phosphatidylinositol 3-phosphate-binding protein 2 (Pib2) is a yeast protein involved in the regulation of TORC1 signaling and lysosomal membrane permeabilization. It is essential for the reactivation of TORC1 following exposure to rapamycin or nutrient starvation. Discovery Pib2 was first identified as a FYVE domain-containing protein able to bind phosphatidylinositol 3-phosphate (PI3P). Pib2 was later identified in a screen for rapamycin sensitivity, along with several other TORC1 regulatory proteins (including Ego1, Gtr1, Gtr2, and other key TORC1 related proteins). Structure Pib2 is a 70.6 kDa protein with 635 amino acids (Uniprot - P53191). Pib2 has 5 weakly conserved motifs among fungi and 2 universally conserved motifs. The partially conserved motifs are found in the N-terminal region of the protein and are generally referred to as regions A-E The universally conserved motifs include a phosphatidylinositol-3-phosphate (PI3P)-binding FYVE domain, and a short tail mot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoinositide 3-kinases
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] |
SNX1
Sorting nexin-1 is a protein that in humans is encoded by the SNX1 gene. The protein encoded by this gene is a sorting nexin. SNX1 is a component of the retromer complex. Function This gene encodes a member of the sorting nexin family. Members of this family contain a phox ( PX) domain, which is a phosphoinositide binding domain, and are involved in intracellular trafficking. This endosomal protein regulates the cell-surface expression of epidermal growth factor receptor. This protein also has a role in sorting protease-activated receptor-1 from early endosomes to lysosome A lysosome () is a membrane-bound organelle found in many animal cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules. A lysosome has a specific composition, of both its membrane prot ...s. This protein may form oligomeric complexes with other family members. References Further reading * * * * * * * * * * * * * * * * * * * External li ... [...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] |
PIK3C3
Phosphatidylinositol 3-kinase catalytic subunit type 3 is an enzyme subunit that in humans is encoded by the ''PIK3C3'' 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 ba .... It's a class III phosphoinositide 3-kinase. References Further reading * * * * * * * * * * * * * * * * * * {{gene-18-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class III PI 3-kinase
Class III PI 3-kinase is a subgroup of the enzyme family, phosphoinositide 3-kinase that share a common protein domain structure, substrate specificity and method of activation. There is only one known class III PI 3-kinase, Vps34, which is also the only PI 3-kinase expressed in all eukaryotic cells. In humans it is encoded by the PIK3C3 gene. In human cells Vps34 associates with a regulatory subunit, PIK3R4(p150, Vps15). Substrate specificity Vps34 is more accurately described as a phosphatidylinositol 3-kinase. ''In vivo'' Vps34 can phosphorylate only phosphatidylinositol to form phosphatidylinositol (3)-phosphate (PtdIns(3)P). Functions Vps34 was first identified in a ''Saccharomyces cerevisiae'' (budding yeast) screen for proteins involved vesicle-mediated vacuolar protein sorting (hence Vps). A number of proteins containing a phosphoinositide binding domain specific for PtdIns(3)P that function in cellular protein trafficking have been identified. Vps34 has been shown to in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HGS (gene)
Hepatocyte growth factor-regulated tyrosine kinase substrate is an enzyme that in humans is encoded by the ''HGS'' gene. Interactions HGS has been shown to interact with: * CLTC * DLG4, * EPS15, * IL2RB, * Merlin, * STAM2, * Signal transducing adaptor molecule * TSG101 Tumor susceptibility gene 101, also known as TSG101, is a human gene that encodes for a cellular protein of the same name. Function The protein encoded by this gene belongs to a group of apparently inactive homologs of ubiquitin-conjugating enzy .... References External links PDBe-KBprovides an overview of all the structure information available in the PDB for Human Hepatocyte growth factor-regulated tyrosine kinase substrate (HGS) Further reading * * * * * * * * * * * * * * * * * {{refend ... [...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] |
PX Domain
The PX domain is a phosphoinositide-binding structural domain involved in targeting of proteins to cell membranes. This domain was first found in P40phox and p47phox domains of NADPH oxidase (phox stands for phagocytic oxidase). It was also identified in many other proteins involved in membrane trafficking, including nexins, Phospholipase D, and phosphoinositide-3- kinases. The PX domain is structurally conserved in eukaryotes, although amino acid sequences show little similarity. PX domains interact primarily with PtdIns(3)P lipids. However some of them bind to phosphatidic acid, PtdIns(3,4)P2, PtdIns(3,5)P2, PtdIns(4,5)P2, and PtdIns(3,4,5)P3. The PX-domain can also interact with other domains and proteins. Human proteins containing this domain Sorting nexins contain this domain. Other examples include: * HS1BP3 * KIF16B (SNX23) * NCF1; NCF1C; NCF4; NISCH * PIK3C2A; PIK3C2B; PIK3C2G; PLD1; PLD2; PXK * RPS6KC1 * SGK3; SH3PXD2A; SNAG1; SNX9 Sorting nexin-9 is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membranes
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
