title: Signal-transducing GTP-binding proteins of mammalian heart and lungs.
abstract: Signal-transducing GTP-binding Proteins of Mammalian Heart and Lungs. Journal of Molecular and Cellular Cardiology (1989) 21 (Suppl I) 91-95. Three distinct G-proteins have been found in mammalian heart sarcolemma: Gi (alpha i = 40 kDa, beta = 36 kDa, and lambda less than 14 kDa), Gp (alpha p = 23 kDa, beta = 36 kDa, and lambda less than 14 kDa), and Gs (alpha s = 42 kDa). ADP-ribosylation of sarcolemmal alpha i by pertussis toxin (PT) or preincubation of sarcolemma with protein kinase C and PMA resulted in increased adenylate cyclase activity and blockade of GTP-dependent inhibition by carbachol whereas the GTP-dependent activating effect of isoproterenol on the adenylate cyclase was preserved. ADP-ribosylation of alpha i in sarcolemma by endogenous NADP-sensitive ADP-ribosyltransferase abolished the PT-induced ADP-ribosylation of alpha i. Gpp (NH)p attenuated the PT-induced ADP-ribosylation of alpha i and promoted the cholera toxin (CT)-induced ADP-ribosylation of alpha s. The CT-induced alpha s ADP-ribosylation was enhanced in the presence of heart cytosol. Soluble Gi- and Gs-proteins were identified in lung cytosol. The 40 kDa alpha i in membrane and soluble fractions was ADP-ribosylated by PT, while the soluble 42 kDa alpha s was ADP-ribosylated by CT in lung tissue. The ADP-ribosylation of soluble alpha i by PT-suppressed guanyl nucleotide binding to Gi. The apparent molecular mass of partially purified soluble Gi was 75 kDa.
authors.affiliation: Institute of Experimental Cardiology, Academy of Medical Sciences, Moscow, USSR.
authors.forename: V A
authors.initials: VA
authors.lastname: Tkachuk
authors.forename: S I
authors.initials: SI
authors.lastname: Hoffenberg
authors.forename: M G
authors.initials: MG
authors.lastname: Starikova
authors.forename: M P
authors.initials: MP
authors.lastname: Panchenko
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D037361:Adenylate Cyclase Toxin; D000818:Animals; D002772:Cholera Toxin / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D037342:Pertussis Toxin; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects; D013552:Swine; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins