title: Reduction of insulin-stimulated glucose uptake by peroxynitrite is concurrent with tyrosine nitration of insulin receptor substrate-1.
abstract: Inducible nitric oxide synthetase plays an essential role in insulin resistance induced by a high-fat diet. The reaction of nitric oxide with superoxide leads to the formation of peroxynitrite (ONOO-), which can modify several proteins. In this study, we investigated whether peroxynitrite impairs insulin-signalling pathway. Our experiments showed that 3-(4-morpholinyl)sydnonimine hydrochloride (SIN-1), a constitutive producer of peroxynitrite, dose-dependently inhibited insulin-stimulated glucose uptake. While SIN-1 did not affect the insulin receptor protein level and tyrosine phosphorylation, it reduced the insulin receptor substrate-1 (IRS-1) protein level, and IRS-1 associated phosphatidylinositol-3 kinase (PI-3 kinase) activity. Although SIN-1 did not induce Ser307 phosphorylation of IRS-1, tyrosine nitration of IRS-1 was detected in SIN-1-treated-Rat1 fibroblasts expressing human insulin receptors. Mass spectrometry showed that peroxynitrite induced at least four nitrated tyrosine residues in rat IRS-1, including Tyr939, which is critical for association of IRS-1 with the p85 subunit of PI-3 kinase. Our results suggest that peroxynitrite reduces the IRS-1 protein level and decreases phosphorylation of IRS-1 concurrent with nitration of its tyrosine residues.
authors.affiliation: Department of Medicine, Metabolism and Endocrinology, Juntendo University, School of Medicine, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nomiyama
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Hikari
authors.initials: H
authors.lastname: Taka
authors.forename: Reiko
authors.initials: R
authors.lastname: Mineki
authors.forename: Toyoyoshi
authors.initials: T
authors.lastname: Uchida
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogihara
authors.forename: Jong Bock
authors.initials: JB
authors.lastname: Choi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uchino
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maegawa
authors.forename: Atsunori
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Kimie
authors.initials: K
authors.lastname: Murayama
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Kawamori
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Watada
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000493:pharmacokinetics*; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins; D051379:Mice; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000737:chemistry* / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D014443:Tyrosine / Q000378:metabolism*
chemical_list: C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; C526296:Irs1 protein, rat; D009566:Nitrates; D010750:Phosphoproteins; D030421:Peroxynitrous Acid; D014443:Tyrosine; C002385:linsidomine; D008981:Molsidomine; D005947:Glucose