Polyphosphoinositide labeling in rat liver plasma membranes is reduced by preincubation with cholera toxin.
Incubation of a crude rat liver plasma membrane preparation with [gamma-32P]ATP resulted in a rapid Mg2+-dependent incorporation of 32P into phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. Preincubation of the membranes with cholera toxin under ADP-ribosylating conditions reduced the labeling of the polyphosphoinositides. This action of cholera toxin required NAD+ and guanine nucleotides, was dose-dependent with respect to cholera toxin, and could not be mimicked by cAMP. It therefore appears that ADP-ribosylation of the stimulatory guanine nucleotide-binding regulatory protein of adenylate cyclase, or another G-protein, in rat liver plasma membranes affects the activity of enzymes in the polyphosphoinositide pathway.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008563:Membrane Lipids / Q000096:biosynthesis*; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000096:biosynthesis*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains
D008563:Membrane Lipids; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D000255:Adenosine Triphosphate; D002772:Cholera Toxin; D008274:Magnesium