| Scientific Background: | Metabolism of inositol phospholipids by intracellular signaling mediators is fundamental to signal transduction in eukaryotic cells. PI-4,5-P2 (PIP2) can be synthesized by phosphorylation of PI-4-P by type I phosphatidylinositol phosphate kinase (PIP5K I), or phosphorylation of PI-5-P by type II PIPK (PIP4K II). PI-4,5-P2 regulation of cellular calcium levels involves its hydrolysis by Phospholipase C (PLC) to produce inositol 1,4,5-triphosphate (IP3) and diacylglycerol (DAG), which serve as second messengers in the import of calcium via IP3-sensitive ion channels and in the activation of PKC, respectively. |
