title: Endoplasmic reticulum thiol oxidase deficiency leads to ascorbic acid depletion and noncanonical scurvy in mice.
abstract: Endoplasmic reticulum (ER) thiol oxidases initiate a disulfide relay to oxidatively fold secreted proteins. We found that combined loss-of-function mutations in genes encoding the ER thiol oxidases ERO1α, ERO1β, and PRDX4 compromised the extracellular matrix in mice and interfered with the intracellular maturation of procollagen. These severe abnormalities were associated with an unexpectedly modest delay in disulfide bond formation in secreted proteins but a profound, 5-fold lower procollagen 4-hydroxyproline content and enhanced cysteinyl sulfenic acid modification of ER proteins. Tissue ascorbic acid content was lower in mutant mice, and ascorbic acid supplementation improved procollagen maturation and lowered sulfenic acid content in vivo. In vitro, the presence of a sulfenic acid donor accelerated the oxidative inactivation of ascorbate by an H(2)O(2)-generating system. Compromised ER disulfide relay thus exposes protein thiols to competing oxidation to sulfenic acid, resulting in depletion of ascorbic acid, impaired procollagen proline 4-hydroxylation, and a noncanonical form of scurvy.
authors.affiliation: University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Cambridge, UK. ez235@medschl.cam.ac.uk
authors.forename: Ester
authors.initials: E
authors.lastname: Zito
authors.forename: Henning Gram
authors.initials: HG
authors.lastname: Hansen
authors.forename: Giles S H
authors.initials: GS
authors.lastname: Yeo
authors.forename: Junichi
authors.initials: J
authors.lastname: Fujii
authors.forename: David
authors.initials: D
authors.lastname: Ron
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D003238:Connective Tissue / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D004220:Disulfides / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009154:Mutation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D054464:Peroxiredoxins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D011347:Procollagen / Q000378:metabolism; D017510:Protein Folding; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012614:Scurvy / Q000209:etiology* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013434:Sulfenic Acids / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D004220:Disulfides; D006023:Glycoproteins; D011347:Procollagen; D013434:Sulfenic Acids; D016212:Transforming Growth Factor beta; C491864:Ero1l protein, mouse; D010088:Oxidoreductases; D054464:Peroxiredoxins; C515981:Prdx4 protein, mouse; D001205:Ascorbic Acid