Guanine nucleotide dependent and independent reconstitution of G-proteins with adenylate cyclase: stimulation or attenuation of the enzyme by Gi alpha subunits.
The alpha subunits of five members of the Gi family of bovine brain proteins were reconstituted with adenylate cyclase in phospholipid vesicles. Our results support both the views that much of the inhibition of the enzyme by Gi is due to the action of its liberated beta gamma subunits, and that the alpha subunits themselves interact with the enzyme. Inhibition of basal or Gs-stimulated adenylate cyclase activity is small or undetectable by alpha subunits of Go, Go* and Gi-2B. On the other hand, adenylate cyclase activity is stimulated by the alpha subunits of Gi-1 and Gi-2A. The G proteins act in the absence of added GTP when reconstituted with phospholipids of low but not high fluidity.
Newton
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Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD 20892.
Klee
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D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology*; D002784:Cholesterol / Q000494:pharmacology; D005227:Fatty Acids / Q000737:chemistry* / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008081:Liposomes; D010713:Phosphatidylcholines / Q000494:pharmacology; D051381:Rats
D005227:Fatty Acids; D008081:Liposomes; D010713:Phosphatidylcholines; D006160:Guanosine Triphosphate; D002784:Cholesterol; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases