Guanosine 5'-O-thiotriphosphate stimulates phospholipase C activity in plasma membranes of rat hepatocytes

• Published in: The Journal of biological chemistry 1985-08, Vol.260 (17), p.9527-9530
• Main Authors: Wallace, M A, Fain, J N
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Calcium - pharmacology; Cell Membrane - drug effects; Cell Membrane - enzymology; Dose-Response Relationship, Drug; Enzymes and enzyme inhibitors; Female; Fundamental and applied biological sciences. Psychology; Guanosine 5'-O-(3-Thiotriphosphate); Guanosine Triphosphate - analogs & derivatives; Guanosine Triphosphate - metabolism; Guanosine Triphosphate - pharmacology; Hydrolases; Liver - drug effects; Liver - enzymology; Phosphatidylinositol Phosphates; Phosphatidylinositols - metabolism; Phospholipases - metabolism; Rats; Thionucleotides - pharmacology; Type C Phospholipases - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)39265-7

The guanine nucleotide analogue, guanosine 5'-O-thiotriphosphate (GTP gamma S) stimulated plasma membrane-associated phospholipase C. Phosphoinositides were the substrates for the reaction. Significant losses of phosphatidylinositol bisphosphate and phosphatidylinositol phosphate occurred at lower doses of GTP gamma S than did significant loss of phosphatidylinositol. Loss of 32P-labeled phosphatidylinositol bisphosphate was equal when plasma membranes were treated with either 100 microM GTP or 100 microM GTP gamma S, but accumulation of inositol trisphosphate was more apparent when the nonhydrolyzable analogue was used. The action of GTP gamma S alone was not dependent on Ca2+ although loss of 32P-labeled phosphoinositides was stimulated by Ca2+ alone or with GTP gamma S. The results are consistent with a role for guanine nucleotide binding proteins in the activation of membrane-bound phosphoinositide-specific phospholipase C.