Evidence for a cholera-toxin-sensitive G-protein involved in the regulation of phosphatidylinositol 4-phosphate kinase of rat liver membranes.
Studies on the phosphorylation of inositol phospholipids of rat liver membranes have shown that [gamma S]pppG stimulates 32P incorporation from [gamma-32P]ATP into PI and PIP. This effect appeared specific for stable GTP analogues and could not be reproduced by other compounds. ADP-ribosylation of the membranes with cholera toxin resulted in a large decrease of PIP2 without changes in the level of PIP. Since an activation of phospholipase C can be ruled out, the lowering of PIP2 is explained on the basis of an inhibition of PIP kinase (EC 2.7.1.68). From these results it appears that a novel cholera-toxin-sensitive G-protein is involved in the regulation of PIP kinase.
Urumow
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Forschergruppe Diabetes, Krankenhaus München-Schwabing, F.R.G.
Wieland
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D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002772:Cholera Toxin / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000502:physiology*; D006150:Guanine Nucleotides / Q000494:pharmacology; D006706:Homeostasis; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D010770:Phosphotransferases / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor); D051381:Rats; D011919:Rats, Inbred Strains
D006150:Guanine Nucleotides; D002772:Cholera Toxin; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D019204:GTP-Binding Proteins