title: The role of beta, gamma-subunits of guanine nucleotide binding proteins in control of a reconstituted signal transmission chain containing purified components of the adenylate cyclase system.
abstract: The properties of a reconstituted signal transmission chain using purified beta 1-adrenoceptor (R), G-protein subunits (G) and adenylate cyclase (C) in lipid vesicles are described. This assay system was used to test beta, gamma-subunits of different origin with respect to their effects on R X G and R X G X C coupling and on the functional properties of GS alpha and Gi alpha. The findings reported here point to large differences in the efficacy of beta, gamma-subunits from different sources assessed by deactivation of [ALF4]-activated rabbit liver GS and pertussis toxin-catalyzed ADP-ribosylation of bovine neutrophil G alpha. This is explained by differences in the interaction domains of the interacting subunits. Furthermore, the sensitivity of R X G and R X G X C coupling to inhibition by beta, gamma-subunits was greater than the effects of beta, gamma-subunits on hormonally activated GTPase activity of GS. One of the consequences of differential inhibition of R X G X C coupling is an amplified response of the signal transmission chain to hormonal activation. This is in agreement with observations reported by Cerione et al.
mesh_terms: D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D002474:Cell-Free System; D004910:Erythrocyte Membrane / Q000032:analysis; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D008081:Liposomes; D008099:Liver / Q000032:analysis; D009206:Myocardium / Q000032:analysis; D009504:Neutrophils / Q000032:analysis; D037342:Pertussis Toxin; D011487:Protein Conformation; D011817:Rabbits; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology; D012374:Rod Cell Outer Segment / Q000032:analysis; D014422:Turkeys; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D008081:Liposomes; D011943:Receptors, Adrenergic, beta; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D007545:Isoproterenol