phosphatidylinositol

phosphatidylinositol
A phosphatidic acid combined with inositol found in biomembranes and a precursor to certain cellular signals. Sometimes referred to as inositide. SYN: phosphoinositide.
- p. 4,5-bisphosphate (PIP2, PtdIns(4,5)P2) p. with two additional sites of phosphorylation; an important constituent of cell membrane phospholipids as well as a precursor of the second messengers, diacylglycerol and inositol 1,4,5-trisphosphate.
- p. 4-phosphate the intermediate in the biosynthesis of p. 4,5-bisphosphate from p..
- p. synthase an enzyme that catalyzes the reaction of CDP-diacylglycerol with inositol to form CMP and p.; found in the endoplasmic reticulum.

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phos·pha·ti·dyl·ino·si·tol (PI) (fos″fə-ti″dəl-ĭ-noґsĭ-tol) a phospholipid in which the sugar inositol is attached to the phosphate group of phosphatidic acid by an ester linkage and the fatty acyl groups are usually arachidonate and stearate; additional phosphates can be attached to the sugar. It is a minor constituent of cell membranes found primarily in the plasma membrane. It is converted by specific kinases to mono- and diphosphorylated forms, phosphoinositides involved in hormonally activated calcium mobilization.

Medical dictionary. 2011.

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  • Phosphatidylinositol 1,4,5 tris phosphate — Phosphatidylinositol Le phosphatidylinositol Le phosphatidylinositol est un phospholipide, constituant des membranes cellulaires. Cette molécule est composée d un groupement phosphatidyl (deux acides gras estérifiés sur une molécules de glycérol …   Wikipédia en Français

  • Phosphatidylinositol phosphate kinases — (PIPK) are kinases that phosphorylate the phosphoinositides PtdIns P and PtdIns P 2 that are derivatives of phosphatidylinositol (PtdIns). It has been found that PtdIns is only phosphorylated on three (3,4,5) of its five hydroxyl groups, possibly …   Wikipedia

  • Phosphatidylinositol bisphosphate — may refer to: * Phosphatidylinositol (3,4) bisphosphate * Phosphatidylinositol (3,5) bisphosphate * Phosphatidylinositol (4,5) bisphosphate …   Wikipedia

  • Phosphatidylinositol (3,5)-bisphosphate — (PtdIns(3,5) P 2) is a minor phospholipid component of cell membranes, yet important in distinguishing cell compartments. The generation of PtdIns(3,5) P 2 in internal membranes by the lipid kinase PIKfyve recruits a number of important proteins… …   Wikipedia

  • Phosphatidylinositol transfer protein, alpha — Phosphatidylinositol transfer protein, alpha, also known as PITPNA, is a human gene. PBB Summary section title = summary text = Phosphatidylinositol transfer proteins are a diverse set of cytosolic phospholipid transfer proteins that are… …   Wikipedia

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  • Phosphatidylinositol 4-phosphate — (PtdIns4 P ) is a precursor of Phosphatidylinositol (4,5) bisphosphate. PtdIns4 P is prevalent in the membrane of the Golgi apparatus.In the Golgi apparatus, PtdIns4 P binds to the GTP binding protein ARF and to effector proteins, including four… …   Wikipedia

  • Phosphatidylinositol phosphate — Phosphatidylinositol phosphates (PIPs) are a class of phospholipids similar to phosphatidylinositols that are also known to have polymorphic behaviour. References * J. M. Seddon, R. H. Templer. Polymorphism of Lipid Water Systems , from the… …   Wikipedia

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