ATP-dependent regulation of phospholipase C in permeabilized 3T3 cells.
Regulation of phospholipase C (PLC) coupled with a G-protein was studied with Swiss 3T3 cells permeabilized by digitonin. In permeabilized cells, activation of phospholipase C required millimolar concentrations of ATP in addition to a G-protein activator, AlF4- or nonhydrolysable GTP analogues. To determine the mechanism of the action of ATP, we examined the effects of ATP analogues. ATP gamma S directly activated phospholipase C in the presence or absence of AlF4-. On the other hand, neither beta,gamma-methylene ATP nor adenyl-5'-yl imidodiphosphate nor ADP beta S could support the AlF4(-)-dependent activation of phospholipase C. The action of ATP gamma S was not through the substrate supply for phospholipase C, because ATP gamma S did not augment the levels of PIP2 or PIP in permeabilized cells. These results suggested the significance of the gamma-phosphate group of ATP and/or phosphorylation by ATP in the activation of phospholipase C by a putative G-protein.
Higashi
K
K
Department of Biochemistry, Meiji College of Pharmacy, Tokyo, Japan.
Ogawara
H
H
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D004072:Digitonin / Q000494:pharmacology; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D010716:Phosphatidylinositols / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*
D010716:Phosphatidylinositols; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D004072:Digitonin