Reactive Oxygen Species-mediated β-Cleavage of the Prion Protein in the Cellular Response to Oxidative Stress

• Published in: The Journal of biological chemistry 2005-10, Vol.280 (43), p.35914-35921
• Main Authors: Watt, Nicole T., Taylor, David R., Gillott, Andrew, Thomas, Daniel A., Perera, W. Sumudhu S., Hooper, Nigel M.
• Format: Article
• Language: English
• Subjects: Animals; Benzimidazoles - pharmacology; Biotinylation; Blotting, Western; Calpain - chemistry; Cell Line, Tumor; Cell Membrane - metabolism; Cell Survival; Coloring Agents - pharmacology; Copper - chemistry; Dimethyl Sulfoxide - chemistry; DNA, Complementary - metabolism; 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; Time Factors; Up-Regulation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M507327200

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 β-cleavage. Here we show that ROS-mediated β-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, PrPΔoct, failed to undergo ROS-mediated β-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 PrPΔoct, PG14, or A116V had reduced viability and glutathione peroxidase activity and increased intracellular free radicals. Thus, lack of ROS-mediated β-cleavage of PrP correlated with the sensitivity of the cells to oxidative stress. These data indicate that the β-cleavage of PrPC is an early and critical event in the mechanism by which PrP protects cells against oxidative stress.