Regulation of phosphoinositide-specific phospholipase C

• Published in: BBA - Molecular Cell Research Vol. 1053; no. 1; pp. 81 - 88
• Main Author: Fain, John N.
• Format: Book Review Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 12.06.1990; Elsevier; North-Holland
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Calcium ion; Enzyme Activation; Enzymes and enzyme inhibitors; Fluoride; Fluorides - pharmacology; Fundamental and applied biological sciences. Psychology; GTP-Binding Proteins - physiology; Guanine nucleotide-binding protein; Hydrolases; Inositol phosphate; Isoenzymes - metabolism; Phosphatidylinositol kinase; Phosphatidylinositols - metabolism; Phospholipase C; Protein kinase C; Protein-Tyrosine Kinases - metabolism; Rats; Receptors, Cell Surface - physiology; Signal Transduction; Type C Phospholipases - metabolism; PIP 2; Protein kinase C; GTP; PIP 3; EGF; PLC; Inositol phosphate; Guanine nucleotide-binding protein; Phospholipase C; Signal transduction; GDP; Calcium ion; Fluoride; GTPγS; PIP; PDGF; IP 3; PI; Phosphatidylinositol kinase; G proteins; 5-HT; GDPβS; PI-3-P; Calcium; Enzyme; Isozyme; Review; Fluorides; Membrane receptor; Regulation(control); Models; Mechanism of action; G protein
• ISSN: 0167-4889; 0006-3002; 1879-2596; 1878-2434
• DOI: 10.1016/0167-4889(90)90029-D

The receptors involved in the regulation of phospholipase C by hormones, neurotransmitters and other ligands have seven transmembrane-spanning hydrophobic regions (seven-helix motif) and no known enzymatic activity. Furthermore these receptors can be isolated as complexes with guanine nucleotide binding (G) proteins. Guanine nucleotides affect the binding of hormones that stimulate phospholipase C and it has been possible to see activation of GTPase activity in membranes upon addition of these ligands. Further indirect evidence for a G p (p stands for phospholipase C activation) protein is the finding that in membranes agonist activation of phospholipase C requires the presence of GTPγS a non-hydrolyzable analog of GTP. Furthermore, fluoride is able to activate phospholipase C but its inhibition of phosphatidylinositol-4′ kinase (PI-4′ kinase) can interfere with efforts to demonstrate this in intact cells. There are four major isozymes of phospholipase C that have been cloned and sequenced. Recently it was found that phospholipase C-γ as well as PI-3′-kinase are substrates for phosphorylation on tyrosine residues by the EGF and PDGF receptors. The PI-3′ kinase is able to convert phosphatidylinositol 4,5-bisphosphate (PIP 2) to phosphatidylinositol 3,4,5-trisphosphate (PIP 3) but the function of this lipid is unknown since it is not a substrate for any known phospholipase C. While much has been learned about the structure and regulation of the phosphoinositide specific kinases and phosphodiesterase enzymes this is a relatively new field in which we can expect many advances during the next few years.