title: Generator-specific targets of mitochondrial reactive oxygen species.
abstract: To understand the role of reactive oxygen species (ROS) in oxidative stress and redox signaling it is necessary to link their site of generation to the oxidative modification of specific targets. Here we have studied the selective modification of protein thiols by mitochondrial ROS that have been implicated as deleterious agents in a number of degenerative diseases and in the process of biological aging, but also as important players in cellular signal transduction. We hypothesized that this bipartite role might be based on different generator sites for "signaling" and "damaging" ROS and a directed release into different mitochondrial compartments. Because two main mitochondrial ROS generators, complex I (NADH:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc1 complex), are known to predominantly release superoxide and the derived hydrogen peroxide (H2O2) into the mitochondrial matrix and the intermembrane space, respectively, we investigated whether these ROS generators selectively oxidize specific protein thiols. We used redox fluorescence difference gel electrophoresis analysis to identify redox-sensitive targets in the mitochondrial proteome of intact rat heart mitochondria. We observed that the modified target proteins were distinctly different when complex I or complex III was employed as the source of ROS. These proteins are potential targets involved in mitochondrial redox signaling and may serve as biomarkers to study the generator-dependent dual role of mitochondrial ROS in redox signaling and oxidative stress.
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany.
authors.forename: Lea
authors.initials: L
authors.lastname: Bleier
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Functional Proteomics, SFB815 Core Unit, Medical School, Goethe-University, D-60590 Frankfurt am Main, Germany.
authors.forename: Ilka
authors.initials: I
authors.lastname: Wittig
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Heide
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany.
authors.forename: Mirco
authors.initials: M
authors.lastname: Steger
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Cluster of Excellence Frankfurt "Macromolecular Complexes," Goethe-University, D-60590 Frankfurt am Main, Germany; Radboud University Medical Center, Nijmegen Center for Mitochondrial Disorders, 6500 GA Nijmegen, The Netherlands.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brandt
authors.affiliation: Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Clinic of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Goethe-University Hospital, Frankfurt am Main, Germany. Electronic address: Stefan.Droese@kgu.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dröse
mesh_terms: D000818:Animals; D004579:Electron Transport; D042967:Electron Transport Complex I / Q000378:metabolism*; D014450:Electron Transport Complex III / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III
keywords: Biomarker; Complex I; Complex III; Free radicals; Mitochondria; Reactive oxygen species; Redox proteomics; Redox signaling; Thiol oxidation