Low reduction potential of Ero1α regulatory disulphides ensures tight control of substrate oxidation

Karl M. Baker, Seema Chakravarthi, Kevin P. Langton, Alyson M. Sheppard, Hui Lu, Neil J. Bulleid

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Formation of disulphide bonds within the mammalian endoplasmic reticulum (ER) requires the combined activities of Ero1α and protein disulphide isomerase (PDI). As Ero1α produces hydrogen peroxide during oxidation, regulation of its activity is critical in preventing ER-generated oxidative stress. Here, we have expressed and purified recombinant human Ero1α and shown that it has activity towards thioredoxin and PDI. The activity towards PDI required the inclusion of glutathione to ensure sustained oxidation. By carrying out site-directed mutagenesis of cysteine residues, we show that Ero1α is regulated by non-catalytic disulphides. The midpoint reduction potential (E°′) of the regulatory disulphides was calculated to be approximately -275 mV making them stable in the redox conditions prevalent in the ER. The stable regulatory disulphides were only partially reduced by PDI (E°′∼-180 mV), suggesting either that this is a mechanism for preventing excessive Ero1α activity and oxidation of PDI or that additional factors are required for Ero1α activation within the mammalian ER. © 2008 European Molecular Biology Organization | Some Rights Reserved.
    Original languageEnglish
    Pages (from-to)2988-2997
    Number of pages9
    JournalEMBO Journal
    Volume27
    Issue number22
    DOIs
    Publication statusPublished - 19 Nov 2008

    Keywords

    • Disulphide formation
    • Ero1α
    • Protein disulphide isomerase
    • Reduction potential

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