title: Redox modulation of tau and microtubule-associated protein-2 by the glutathione/glutaredoxin reductase system.
abstract: Alterations in the redox status of proteins have been implicated in the pathology of several neurodegenerative diseases including Alzheimer's and Parkinson's. We report that peroxynitrite and H2O2-induced disulfides in the porcine brain microtubule-associated proteins tau and microtubule-associated protein-2 are substrates for the glutaredoxin reductase system composed of glutathione reductase, human or Escherichia coli glutaredoxin, reduced glutathione, and NADPH. Oxidation and reduction of cysteines in tau and microtubule-associated protein-2 were quantitated by monitoring the incorporation of 5-iodoacetamido-fluorescein, a thiol-specific labeling reagent. Reduction of disulfide bonds in the microtubule-associated proteins by the glutaredoxin reductase system restored their ability to promote the assembly of microtubules composed of purified porcine tubulin. Thiol-disulfide exchange between oxidized glutathione and the microtubule-associated proteins was detected by monitoring protein oxidation and was quantitated by measuring reduced glutathione by HPLC.
authors.affiliation: Department of Chemistry, The College of William and Mary, P.O. Box 8795, Williamsburg, VA 23187-8795, USA. lmland@wm.edu
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Landino
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Robinson
authors.forename: Tabor E
authors.initials: TE
authors.lastname: Skreslet
authors.forename: Diana M
authors.initials: DM
authors.lastname: Cabral
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D005452:Fluoresceins / Q000494:pharmacology; D054477:Glutaredoxins; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D005980:Glutathione Reductase / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008869:Microtubule-Associated Proteins / Q000737:chemistry*; D008870:Microtubules / Q000378:metabolism; D008956:Models, Chemical; D009249:NADP; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000494:pharmacology; D013438:Sulfhydryl Compounds; D013552:Swine; D013997:Time Factors; D016875:tau Proteins / Q000737:chemistry*
chemical_list: D004220:Disulfides; D005452:Fluoresceins; D054477:Glutaredoxins; D008869:Microtubule-Associated Proteins; D016877:Oxidants; D013438:Sulfhydryl Compounds; D016875:tau Proteins; D030421:Peroxynitrous Acid; D009249:NADP; C015296:5-iodoacetamidofluorescein; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D005980:Glutathione Reductase; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen