Gz-mediated hormonal inhibition of cyclic AMP accumulation.
Hormones inhibit synthesis of adenosine 3',5'-monophosphate (cAMP) in most cells via receptors coupled to pertussis toxin (PTX)-sensitive guanine nucleotide-binding (G) proteins. Mutationally activated alpha subunits of Gi2 (alpha i2) constitutively inhibit cAMP accumulation when transfected into cells. Cells have now been transfected with mutant alpha subunits of four other G proteins--Gz, a PTX-insensitive G protein of unknown function, and Gi1, Gi3, and G(o), which are PTX-sensitive. Mutant alpha z, alpha i1, and alpha i3 inhibited cAMP accumulation but alpha o did not. Moreover, expression of wild-type alpha z produced cells in which PTX did not block hormonal inhibition of cAMP accumulation. Thus, Gz can trigger an effector pathway in response to hormone receptors that ordinarily interact with PTX-sensitive Gi proteins.
Department of Pharmacology, University of California, San Francisco 94143.
Y H
YH
Wong
B R
BR
Conklin
H R
HR
Bourne
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D000068438:Brimonidine Tartrate; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D015232:Dinoprostone / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D006728:Hormones / Q000502:physiology*; D066298:In Vitro Techniques; D008246:Lysophospholipids / Q000494:pharmacology; D037342:Pertussis Toxin; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D006063:Chorionic Gonadotropin; D006728:Hormones; D008246:Lysophospholipids; D011810:Quinoxalines; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D000068438:Brimonidine Tartrate; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D015232:Dinoprostone; D004298:Dopamine