Journal article
Hyperactivity of the Ero1α Oxidase Elicits Endoplasmic Reticulum Stress but No Broad Antioxidant Response
University of Copenhagen1
University of Basel2
Department of Systems Biology, Technical University of Denmark3
Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark4
Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark5
CFB - Metagenomic Systems Biology, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark6
Aarhus University7
Center for Biological sequence analysis, Technical University of Denmark8
Oxidizing equivalents for the process of oxidative protein folding in the endoplasmic reticulum (ER) of mammalian cells are mainly provided by the Ero1α oxidase. The molecular mechanisms that regulate Ero1α activity in order to harness its oxidative power are quite well understood. However, the overall cellular response to oxidative stress generated by Ero1α in the lumen of the mammalian ER is poorly characterized.
Here we investigate the effects of overexpressing a hyperactive mutant (C104A/C131A) of Ero1α. We show that Ero1α hyperactivity leads to hyperoxidation of the ER oxidoreductase ERp57 and induces expression of two established unfolded protein response (UPR) targets, BiP (immunoglobulin-binding protein) and HERP (homocysteine-induced ER protein).
These effects could be reverted or aggravated by N-acetylcysteine and buthionine sulfoximine, respectively. Because both agents manipulate the cellular glutathione redox buffer, we conclude that the observed effects of Ero1α-C104A/C131A overexpression are likely caused by an oxidative perturbation of the ER glutathione redox buffer.
In accordance, we show that Ero1α hyperactivity affects cell viability when cellular glutathione levels are compromised. Using microarray analysis, we demonstrate that the cell reacts to the oxidative challenge caused by Ero1α hyperactivity by turning on the UPR. Moreover, this analysis allowed the identification of two new targets of the mammalian UPR, CRELD1 and c18orf45.
Interestingly, a broad antioxidant response was not induced. Our findings suggest that the hyperoxidation generated by Ero1α-C104A/C131A is addressed in the ER lumen and is unlikely to exert oxidative injury throughout the cell.
Language: | English |
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Publisher: | American Society for Biochemistry and Molecular Biology |
Year: | 2012 |
Pages: | 39513-39523 |
ISSN: | 10678816 , 00219258 and 1083351x |
Types: | Journal article |
DOI: | 10.1074/jbc.M112.405050 |
ORCIDs: | 0000-0002-7050-3354 , 0000-0002-2832-730X , 0000-0002-3194-0287 and 0000-0002-7018-0137 |
Endoplasmic Reticulum (ER) Ero1α Glutathione Hydrogen Peroxide Oxidative Stress Redox Homeostasis Redox Regulation Unfolded Protein Response xCT
Acetylcysteine Amino Acid Substitution Buthionine Sulfoximine CRELD1 protein, human Cell Adhesion Molecules ERO1A protein, human Endoplasmic Reticulum Stress Enzyme Inhibitors Extracellular Matrix Proteins Free Radical Scavengers HEK293 Cells Humans Membrane Glycoproteins Mutation, Missense Oxidation-Reduction Oxidoreductases Protein Structure and Folding