title: Redox Activation of the Universally Conserved ATPase YchF by Thioredoxin 1.
abstract: OBJECTIVE
  YchF/Ola1 are unconventional members of the universally conserved GTPase family because they preferentially hydrolyze ATP rather than GTP. These ATPases have been associated with various cellular processes and pathologies, including DNA repair, tumorigenesis, and apoptosis. In particular, a possible role in regulating the oxidative stress response has been suggested for both bacterial and human YchF/Ola1. In this study, we analyzed how YchF responds to oxidative stress and how it potentially regulates the antioxidant response.
  
  
  RESULTS
  Our data identify a redox-regulated monomer-dimer equilibrium of YchF as a key event in the functional cycle of YchF. Upon oxidative stress, the oxidation of a conserved and surface-exposed cysteine residue promotes YchF dimerization, which is accompanied by inhibition of the ATPase activity. No dimers were observed in a YchF mutant lacking this cysteine. In vitro, the YchF dimer is dissociated by thioredoxin 1 (TrxA) and this stimulates the ATPase activity. The physiological significance of the YchF-thioredoxin 1 interaction was demonstrated by in vivo cross-linking, which validated this interaction in living cells. This approach also revealed that both the ATPase domain and the helical domain of YchF are in contact with TrxA.
  
  
  METHODS
  YchF/Ola1 are the first redox-regulated members of the universally conserved GTPase family and are inactivated by oxidation of a conserved cysteine residue within the nucleotide-binding motif.
  
  
  CONCLUSIONS
  Our data provide novel insights into the regulation of the so far ill-defined YchF/Ola1 family of proteins and stipulate their role as negative regulators of the oxidative stress response.
authors.affiliation: 1 Institut für Biochemie und Molekularbiologie, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Liya
authors.initials: L
authors.lastname: Hannemann
authors.affiliation: 2 Faculty of Biology, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .|3 BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Ida
authors.initials: I
authors.lastname: Suppanz
authors.affiliation: 1 Institut für Biochemie und Molekularbiologie, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .|2 Faculty of Biology, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Qiaorui
authors.initials: Q
authors.lastname: Ba
authors.affiliation: 1 Institut für Biochemie und Molekularbiologie, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Katherine
authors.initials: K
authors.lastname: MacInnes
authors.affiliation: 2 Faculty of Biology, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .|3 BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Friedel
authors.initials: F
authors.lastname: Drepper
authors.affiliation: 2 Faculty of Biology, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .|3 BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Bettina
authors.initials: B
authors.lastname: Warscheid
authors.affiliation: 1 Institut für Biochemie und Molekularbiologie, Albert-Ludwigs-Universität Freiburg , Freiburg, Germany .
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Koch
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism*; D003545:Cysteine / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000235:genetics*; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D000975:Antioxidants; D029968:Escherichia coli Proteins; D013879:Thioredoxins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C559743:YchF protein, E. coli; D005978:Glutathione; D003545:Cysteine