title: H2O2-dependent hyperoxidation of peroxiredoxin 6 (Prdx6) plays a role in cellular toxicity via up-regulation of iPLA2 activity.
abstract: Peroxiredoxin 6 (Prdx6) is a bifunctional enzyme with peroxidase activity and Ca2+-independent phospholipase A2 (iPLA2) activity. Here, we report that H2O2-induced cellular toxicity acts through Prdx6 hyperoxidation. Under high concentrations of H2O2 (> 100 microm), Prdx6, and 2-Cys Prdxs were hyperoxidized. Contrary to hyperoxidation of 2-Cys Prdxs, hyperoxidation of Prdx6 was irreversible in vivo. Surprisingly, H2O2-induced cell cycle arrest at the G2/M transition correlated with hyperoxidation and increased iPLA2 activity of Prdx6. This arrest was also associated with up-regulation of p53 and p21 and with down-regulation of cyclin B1. Furthermore, the H2O2-mediated increase in iPLA2 activity was dramatically abolished in a hyperoxidation mutant (C47A), an iPLA2 mutant (S32A), and a double mutant (C47A/S32A) of Prdx6, demonstrating the essential requirement of Prdx6 C47 hyperoxidation for its iPLA2 activity. Together, our results demonstrate that H2O2-mediated hyperoxidation of Prdx6 induces cell cycle arrest at the G2/M transition through up-regulation of iPLA2 activity.
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea.
authors.forename: So Yong
authors.initials: SY
authors.lastname: Kim
authors.forename: Hee-Yeon
authors.initials: HY
authors.lastname: Jo
authors.forename: Mi Hye
authors.initials: MH
authors.lastname: Kim
authors.forename: Yun-yi
authors.initials: YY
authors.lastname: Cha
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Choi
authors.forename: Jae-Hyuck
authors.initials: JH
authors.lastname: Shim
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Kim
authors.forename: Ki-Young
authors.initials: KY
authors.lastname: Lee
mesh_terms: D019943:Amino Acid Substitution; D002455:Cell Division / Q000187:drug effects* / Q000235:genetics; D019926:Cyclin B / Q000096:biosynthesis / Q000235:genetics; D056744:Cyclin B1; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D016195:G2 Phase / Q000187:drug effects* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects* / Q000235:genetics; D054522:Group VI Phospholipases A2 / Q000096:biosynthesis* / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D020125:Mutation, Missense; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D054465:Peroxiredoxin VI / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1; D016877:Oxidants; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D006861:Hydrogen Peroxide; C515977:PRDX6 protein, human; D054465:Peroxiredoxin VI; D054522:Group VI Phospholipases A2; C516475:PLA2G6 protein, human