The FAD- and O(2)-dependent reaction cycle of Ero1-mediated oxidative protein folding in the endoplasmic reticulum.
The endoplasmic reticulum (ER) supports disulfide formation through an essential protein relay involving Ero1p and protein disulfide isomerase (PDI). We find that in addition to having a tightly associated flavin adenine dinucleotide (FAD) moiety, yeast Ero1p is highly responsive to small changes in physiological levels of free FAD. This sensitivity underlies the dependence of oxidative protein folding on cellular FAD levels. FAD is synthesized in the cytosol but can readily enter the ER lumen and promote Ero1p-catalyzed oxidation. Ero1p then uses molecular oxygen as its preferred terminal electron acceptor. Thus Ero1p directly couples disulfide formation to the consumption of molecular oxygen, but its activity is modulated by free lumenal FAD levels, potentially linking disulfide formation to a cell's nutritional or metabolic status.
Tu
Benjamin P
BP
Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, CA 94143, USA.
Weissman
Jonathan S
JS
D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000378:metabolism; D004583:Electrons; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D008954:Models, Biological; D008956:Models, Chemical; D050862:Oxidoreductases Acting on Sulfur Group Donors; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D017510:Protein Folding; D012259:Ribonuclease, Pancreatic / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013482:Superoxide Dismutase / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D015003:Yeasts / Q000502:physiology
D004220:Disulfides; D006023:Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D005182:Flavin-Adenine Dinucleotide; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D050862:Oxidoreductases Acting on Sulfur Group Donors; C113186:ERO1 protein, S cerevisiae; D012259:Ribonuclease, Pancreatic; D019704:Protein Disulfide-Isomerases; D010100:Oxygen