title: Adenylyl cyclase and G-proteins in Phytomonas.
abstract: Phytomonas sp. membranes have an adenylyl cyclase activity which is greater in the presence of Mn2+ than with Mg2+. The Mg2+ and Mn2+ activity ratio varies from one membrane preparation to another, suggesting that the adenylyl cyclase has a variable activation state. A[35S]GTP-gamma-S-binding activity with a Kd of 171 nM was detected in Phytomonas membranes. Incubation of these membranes with activated cholera or pertussis toxin and [adenylate 23P]NAD+ led to incorporation of radioactivity into bands of about 40-44 kDa. Crude membranes were electrophoresed on SDS-polyacrylamide gels and analyzed, by Western blotting, with the 9188 anti-alpha[s] antibody and the AS/7 antibody (anti-alpha[i], anti-alpha[i1], and anti-alpha[i2]. These procedures resulted in the identification of polypeptides of approximately 40-44 kDa. Phytomonas adenylyl cyclase could be activated by treatment of membrane preparations with cholera toxin, in the presence of NAD+, while similar treatment with pertussis toxin did not affect this enzyme activity. These studies indicate that in Phytomonas, adenylyl cyclase activity is coupled to an unknown receptor entity through G alpha[s] proteins.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular and Facultad de Ciencias Exactas y Naturales, Obligado 2490, 1428 Buenos Aires, Argentina.
authors.forename: M D
authors.initials: MD
authors.lastname: Farber
authors.forename: A E
authors.initials: AE
authors.lastname: Montagna
authors.forename: C
authors.initials: C
authors.lastname: Paveto
authors.forename: M
authors.initials: M
authors.lastname: Dollet
authors.forename: M
authors.initials: M
authors.lastname: Sanchex-Moreno
authors.forename: A
authors.initials: A
authors.lastname: Osuna
authors.forename: H N
authors.initials: HN
authors.lastname: Torres
authors.forename: M M
authors.initials: MM
authors.lastname: Flawia
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D002772:Cholera Toxin / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006160:Guanosine Triphosphate / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism / Q000494:pharmacology; D037342:Pertussis Toxin; D011485:Protein Binding; D014351:Trypanosomatina / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D001427:Bacterial Toxins; D002413:Cations, Divalent; D010566:Virulence Factors, Bordetella; D009243:NAD; D008345:Manganese; D000244:Adenosine Diphosphate; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D037342:Pertussis Toxin; D020962:Heterotrimeric GTP-Binding Proteins; D000262:Adenylyl Cyclases; D008274:Magnesium