title: In the budding yeast Kluyveromyces marxianus, adenylate cyclase is regulated by Ras protein(s) in vitro.
abstract: The presence of adenylate cyclase activity was first demonstrated in membrane fractions from the budding yeast Kluyveromyces marxianus. The enzyme showed a Mn(2+)- and Mg(2+)-dependent activity, with optimal pH at around 6 as observed in other yeast species. As in Saccharomyces cerevisiae, where adenylate cyclase is regulated by RAS1 and RAS2, we detected a guanyl nucleotide-dependent activity. Interestingly Y13-259 monoclonal antibody, raised against mammalian p21Ha-ras, inhibited Mg2+ plus GTP-gamma-S-dependent cAMP production, suggesting that the GTP binding proteins involved in adenylate cyclase regulation could be Ras proteins. The same antibody recognized on Western blot and immunoprecipitated a 40 kDa polypeptide from K. marxianus crude membranes. This polypeptide was not detected by an anti-RAS2 polyclonal antibody raised against S. cerevisiae RAS2 protein, suggesting that Ras proteins from the two species could be structurally different.
authors.affiliation: Dipartimento di Biologia Animale, Università di Torino, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Verzotti
authors.forename: M
authors.initials: M
authors.lastname: Geymonat
authors.forename: F
authors.initials: F
authors.lastname: Valetti
authors.forename: L
authors.initials: L
authors.lastname: Lanzetti
authors.forename: C
authors.initials: C
authors.lastname: Giunta
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism; D006150:Guanine Nucleotides / Q000494:pharmacology; D007716:Kluyveromyces / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008566:Membranes / Q000737:chemistry; D011233:Precipitin Tests; D018631:ras Proteins / Q000276:immunology / Q000378:metabolism*
chemical_list: D006150:Guanine Nucleotides; D008345:Manganese; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D018631:ras Proteins; D000262:Adenylyl Cyclases; D008274:Magnesium