title: Human ER Oxidoreductin-1α (Ero1α) Undergoes Dual Regulation through Complementary Redox Interactions with Protein-Disulfide Isomerase.
abstract: In the mammalian endoplasmic reticulum, oxidoreductin-1α (Ero1α) generates protein disulfide bonds and transfers them specifically to canonical protein-disulfide isomerase (PDI) to sustain oxidative protein folding. This oxidative process is coupled to the reduction of O2to H2O2on the bound flavin adenine dinucleotide cofactor. Because excessive thiol oxidation and H2O2generation cause cell death, Ero1α activity must be properly regulated. In addition to the four catalytic cysteines (Cys94, Cys99, Cys104, and Cys131) that are located in the flexible active site region, the Cys208-Cys241pair located at the base of another flexible loop is necessary for Ero1α regulation, although the mechanistic basis is not fully understood. The present study revealed that the Cys208-Cys241disulfide was reduced by PDI and other PDI family members during PDI oxidation. Differential scanning calorimetry and small angle X-ray scattering showed that mutation of Cys208and Cys241did not grossly affect the thermal stability or overall shape of Ero1α, suggesting that redox regulation of this cysteine pair serves a functional role. Moreover, the flexible loop flanked by Cys208and Cys241provides a platform for functional interaction with PDI, which in turn enhances the oxidative activity of Ero1α through reduction of the Cys208-Cys241disulfide. We propose a mechanism of dual Ero1α regulation by dynamic redox interactions between PDI and the two Ero1α flexible loops that harbor the regulatory cysteines.
authors.affiliation: From the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Kanemura
authors.affiliation: From the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.|RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Okumura
authors.affiliation: RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan.
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Yutani
authors.affiliation: the Division of Molecular & Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ramming
authors.affiliation: RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hikima
authors.affiliation: the Division of Molecular & Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland.|the Berufsfachschule Gesundheit Baselland, 4142 Münchenstein, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Appenzeller-Herzog
authors.affiliation: RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan.|the Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585, Japan.|the Department of Functional Molecular Science, SOKENDAI (Graduate University for Advanced Studies), Kanagawa 240-0193, Japan, and.
authors.forename: Shuji
authors.initials: S
authors.lastname: Akiyama
authors.affiliation: From the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan, kinaba@tagen.tohoku.ac.jp.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo, 102-0076, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Inaba
mesh_terms: D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019704:Protein Disulfide-Isomerases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D014961:X-Ray Diffraction
chemical_list: D008562:Membrane Glycoproteins; C405327:ERO1A protein, human; D010088:Oxidoreductases; D019704:Protein Disulfide-Isomerases
keywords: disulfide; endoplasmic reticulum (ER); hydrogen peroxide; protein-disulfide isomerase; redox regulation