title: Reactive oxygen species-mediated beta-cleavage of the prion protein in the cellular response to oxidative stress.
abstract: The cellular prion protein (PrP(C)) is critical for the development of prion diseases. However, the physiological role of PrP(C) is less clear, although a role in the cellular resistance to oxidative stress has been proposed. PrP(C) is cleaved at the end of the copper-binding octapeptide repeats through the action of reactive oxygen species (ROS), a process termed beta-cleavage. Here we show that ROS-mediated beta-cleavage of cell surface PrP(C) occurs within minutes and was inhibited by the hydroxyl radical quencher dimethyl sulfoxide and by an antibody against the octapeptide repeats. A construct of PrP lacking the octapeptide repeats, PrPDeltaoct, failed to undergo ROS-mediated beta-cleavage, as did two mutant forms of PrP, PG14 and A116V, associated with human prion diseases. As compared with cells expressing wild type PrP, when challenged with H2O2 and Cu2+, cells expressing PrPdeltaoct, PG14, or A116V had reduced viability and glutathione peroxidase activity and increased intracellular free radicals. Thus, lack of ROS-mediated beta-cleavage of PrP correlated with the sensitivity of the cells to oxidative stress. These data indicate that the beta-cleavage of PrP(C) is an early and critical event in the mechanism by which PrP protects cells against oxidative stress.
authors.affiliation: Proteolysis Research Group, School of Biochemistry and Microbiology, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Nicole T
authors.initials: NT
authors.lastname: Watt
authors.forename: David R
authors.initials: DR
authors.lastname: Taylor
authors.forename: Andrew
authors.initials: A
authors.lastname: Gillott
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Thomas
authors.forename: W Sumudhu S
authors.initials: WS
authors.lastname: Perera
authors.forename: Nigel M
authors.initials: NM
authors.lastname: Hooper
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D019921:Biotinylation; D015153:Blotting, Western; D002154:Calpain / Q000737:chemistry; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D004396:Coloring Agents / Q000494:pharmacology; D003300:Copper / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004705:Endocytosis; D019286:Endopeptidase K / Q000378:metabolism; D000939:Epitopes / Q000737:chemistry; D005456:Fluorescent Dyes / Q000494:pharmacology; D005609:Free Radicals; D005979:Glutathione Peroxidase / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D047468:Immunoprecipitation; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D011328:Prions / Q000737:chemistry*; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins / Q000737:chemistry; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D001562:Benzimidazoles; D004396:Coloring Agents; D018076:DNA, Complementary; D000939:Epitopes; D005456:Fluorescent Dyes; D005609:Free Radicals; D010455:Peptides; D011328:Prions; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D003300:Copper; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D019286:Endopeptidase K; D002154:Calpain; C017807:bisbenzimide ethoxide trihydrochloride; D010100:Oxygen; D004121:Dimethyl Sulfoxide