title: 90-kDa ribosomal S6 kinase 1 is inhibited by S-glutathionylation of its active-site cysteine residue during oxidative stress.
abstract: Previously, we reported that p90-RSK1 phosphorylates neuronal nitric oxide synthase (nNOS) at Ser847 in cells treated with mitogens, leading to the inhibition of NOS activity. Here, we show RSK1 Cys223 glutathionylation limits the activity of the enzyme following an oxidative stimulus and attenuates the nNOS phosphorylation. Treatment of RSK1 with diamide/glutathione results in inactivation of the enzyme in vitro. Mutagenesis studies confirmed that S-glutathionylation of Cys223 is both necessary and sufficient for this inhibition of RSK1. In transfected cells expressing RSK1 and nNOS, treatment with diamide caused a decrease in EGF-induced phosphorylation of nNOS at Ser847. Cells expressing mutant RSK1 (C223S) proved resistant in this regard. Thus, RSK1 Cys223 glutathionylation may contribute to regulate the levels of NO in the brain.
authors.affiliation: Department of Pharmacology, High Technology Research Center, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takata
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D020134:Catalytic Domain; D003545:Cysteine / Q000378:metabolism*; D003958:Diamide / Q000737:chemistry; D004815:Epidermal Growth Factor / Q000502:physiology; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007700:Kinetics; D051379:Mice; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D018384:Oxidative Stress; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003958:Diamide; D004815:Epidermal Growth Factor; D052248:Nitric Oxide Synthase Type I; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C512964:Rps6ka1 protein, mouse; D005978:Glutathione; D003545:Cysteine