Phosphatidylinositol (4,5)-bisphosphate

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Phosphatidylinositol (4,5)-bisphosphate
Molecular formula C47H85O19P3
Molar mass 1047.09
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

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Phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2) is a minor phospholipid component of cell membranes. PtdIns(4,5)P2 is enriched at the plasma membrane where it is an important substrate for a number of important signaling proteins.[1]

Phospholipase C hydrolyzes the phosphodiester link in PtdIns(4,5)P2 forming inositol 1,4,5-triphosphate (InsP3) and diacylglycerol (DAG).

PtdIns(4,5)P22 is formed primarily by the type I phosphatidylinositol 4 phosphate 5 kinases from PI(4)P.

Class I PI 3-kinases phosphorylate PtdIns(4,5)P2 forming phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3). Both PtdIns(3,4,5)P3 and PtdIns(4,5)P2 not only act as substrates for enzymes but also serve as docking phospholipids that bind specific domains that promote the recruitment of proteins to the plasma membrane and subsequent activation of signaling cascades.

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  1. Strachan T, Read AP (1999). Leptospira. In: Human Molecular Genetics (2nd ed. ed.). Wiley-Liss. (via NCBI Bookshelf) ISBN 0-471-33061-2.