title: Regulation of the V-type ATPase by redox modulation.
abstract: ATP-hydrolysis and proton pumping by the V-ATPase (vacuolar proton-translocating ATPase) are subject to redox regulation in mammals, yeast and plants. Oxidative inhibition of the V-ATPase is ascribed to disulfide-bond formation between conserved cysteine residues at the catalytic site of subunit A. Subunits containing amino acid substitutions of one of three conserved cysteine residues of VHA-A were expressed in a vha-A null mutant background in Arabidopsis. In vitro activity measurements revealed a complete absence of oxidative inhibition in the transgenic line expressing VHA-A C256S, confirming that Cys(256) is necessary for redox regulation. In contrast, oxidative inhibition was unaffected in plants expressing VHA-A C279S and VHA-A C535S, indicating that disulfide bridges involving these cysteine residues are not essential for oxidative inhibition. In vivo data suggest that oxidative inhibition might not represent a general regulatory mechanism in plants.
authors.affiliation: Plant Biochemistry and Physiology, Faculty of Biology-W5, Bielefeld University, 33501 Bielefeld, Germany. thorsten.seidel@uni-bielefeld.de
authors.forename: Thorsten
authors.initials: T
authors.lastname: Seidel
authors.forename: Stefan
authors.initials: S
authors.lastname: Scholl
authors.forename: Melanie
authors.initials: M
authors.lastname: Krebs
authors.forename: Florian
authors.initials: F
authors.lastname: Rienmüller
authors.forename: Irene
authors.initials: I
authors.lastname: Marten
authors.forename: Rainer
authors.initials: R
authors.lastname: Hedrich
authors.forename: Miriam
authors.initials: M
authors.lastname: Hanitzsch
authors.forename: Patricia
authors.initials: P
authors.lastname: Janetzki
authors.forename: Karl-Josef
authors.initials: KJ
authors.lastname: Dietz
authors.forename: Karin
authors.initials: K
authors.lastname: Schumacher
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D003545:Cysteine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D018408:Patch-Clamp Techniques; D030821:Plants, Genetically Modified; D011487:Protein Conformation; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D025262:Vacuolar Proton-Translocating ATPases; D003545:Cysteine