NR ATUZ
AU Watt,N.T.; Taylor,D.R.; Gillott,A.; Thomas,D.A.; Perera,W.S.S.; Hooper,N.M.
TI Reactive oxygen species-mediated beta-cleavage of the prion protein in the cellular response to oxidative stress
QU The Journal of Biological Chemistry 2005 Oct 28; 280(43): 35914-21
PT journal article
AB The cellular prion protein (PrPc) is critical for the development of prion diseases. However, the physiological role of PrPc is less clear, although a role in the cellular resistance to oxidative stress has been proposed. PrPc 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 PrPc 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 PrPc is an early and critical event in the mechanism by which PrP protects cells against oxidative stress.
MH Animals; Benzimidazoles/pharmacology; Biotinylation; Blotting, Western; Calpain/chemistry; Cell Line, Tumor; Cell Membrane/metabolism; Cell Survival; Coloring Agents/pharmacology; Copper/chemistry; DNA, Complementary/metabolism; Dimethyl Sulfoxide/chemistry; Electrophoresis, Polyacrylamide Gel; Endocytosis; Endopeptidase K/metabolism; Epitopes/chemistry; Fluorescent Dyes/pharmacology; Free Radicals; Glutathione Peroxidase/metabolism; Glycosylation; Humans; Hydrogen Peroxide/chemistry; Immunoprecipitation; Mice; Microscopy, Fluorescence; Mutation; *Oxidative Stress; Oxygen/chemistry; Peptides/chemistry; Prions/*chemistry; *Reactive Oxygen Species; Recombinant Proteins/chemistry; Research Support, Non-U.S. Gov't; Time Factors; Up-Regulation
AD Proteolysis Research Group, School of Biochemistry and Microbiology, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT, United Kingdom.
SP englisch
PO USA