title: ROS-Mediated Inhibition ofS-nitrosoglutathione Reductase Contributes to the Activation of Anti-oxidative Mechanisms.
abstract: Nitric oxide (NO) has emerged as a signaling molecule in plants being involved in diverse physiological processes like germination, root growth, stomata closing and response to biotic and abiotic stress.S-nitrosoglutathione (GSNO) as a biological NO donor has a very important function in NO signaling since it can transfer its NO moiety to other proteins (trans-nitrosylation). Suchtrans-nitrosylation reactions are equilibrium reactions and depend on GSNO level. The breakdown of GSNO and thus the level ofS-nitrosylated proteins are regulated by GSNO-reductase (GSNOR). In this way, this enzyme controlsS-nitrosothiol levels and regulates NO signaling. Here we report thatArabidopsis thalianaGSNOR activity is reversibly inhibited by H2O2in vitroand by paraquat-induced oxidative stressin vivo. Light scattering analyses of reduced and oxidized recombinant GSNOR demonstrated that GSNOR proteins form dimers under both reducing and oxidizing conditions. Moreover, mass spectrometric analyses revealed that H2O2-treatment increased the amount of oxidative modifications on Zn2+-coordinating Cys47 and Cys177. Inhibition of GSNOR results in enhanced levels ofS-nitrosothiols followed by accumulation of glutathione. Moreover, transcript levels of redox-regulated genes and activities of glutathione-dependent enzymes are increased ingsnor-koplants, which may contribute to the enhanced resistance against oxidative stress. In sum, our results demonstrate that reactive oxygen species (ROS)-dependent inhibition of GSNOR is playing an important role in activation of anti-oxidative mechanisms to damping oxidative damage and imply a direct crosstalk between ROS- and NO-signaling.
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Izabella
authors.initials: I
authors.lastname: Kovacs
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Holzmeister
authors.affiliation: Centre for Organismal Studies Heidelberg, Ruprecht-Karls-Universität Heidelberg Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Wirtz
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Arie
authors.initials: A
authors.lastname: Geerlof
authors.affiliation: Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fröhlich
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Gaby
authors.initials: G
authors.lastname: Römling
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Gitto T
authors.initials: GT
authors.lastname: Kuruthukulangarakoola
authors.affiliation: Centre for Organismal Studies Heidelberg, Ruprecht-Karls-Universität Heidelberg Heidelberg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Linster
authors.affiliation: Centre for Organismal Studies Heidelberg, Ruprecht-Karls-Universität Heidelberg Heidelberg, Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hell
authors.affiliation: Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München Munich, Germany.
authors.forename: Georg J
authors.initials: GJ
authors.lastname: Arnold
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental HealthNeuherberg, Germany; Lehrstuhl für Biochemische Pflanzenpathologie, Technische Universität MünchenFreising, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Durner
authors.affiliation: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München - German Research Center for Environmental Health Neuherberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Lindermayr
keywords: Arabidopsis thaliana; S-nitrosoglutathione reductase; S-nitrosothiols; hydrogen peroxide; nitric oxide; oxidative stress; paraquat; reactive oxygen species