title: Glutaredoxin exerts an antiapoptotic effect by regulating the redox state of Akt.
abstract: Glutaredoxin (GRX) is a small dithiol protein involved in various cellular functions, including the redox regulation of certain enzyme activities. GRX functions via a disulfide exchange reaction by utilizing the active site Cys-Pro-Tyr-Cys. Here we demonstrated that overexpression of GRX protected cells from hydrogen peroxide (H2O2)-induced apoptosis by regulating the redox state of Akt. Akt was transiently phosphorylated, dephosphorylated, and then degraded in cardiac H9c2 cells undergoing H2O2-induced apoptosis. Under stress, Akt underwent disulfide bond formation between Cys-297 and Cys-311 and dephosphorylation in accordance with an increased association with protein phosphatase 2A. Overexpression of GRX protected Akt from H2O2-induced oxidation and suppressed recruitment of protein phosphatase 2A to Akt, resulting in a sustained phosphorylation of Akt and inhibition of apoptosis. This effect was reversed by cadmium, an inhibitor of GRX. Furthermore an in vitro assay revealed that GRX reduced oxidized Akt in concert with glutathione, NADPH, and glutathione-disulfide reductase. Thus, GRX plays an important role in protecting cells from apoptosis by regulating the redox state of Akt.
authors.affiliation: Department of Biochemistry and Molecular Biology in Disease, Atomic Bomb Disease Institute, Nagasaki University School of Medicine, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Murata
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Ihara
authors.forename: Hajime
authors.initials: H
authors.lastname: Nakamura
authors.forename: Junji
authors.initials: J
authors.lastname: Yodoi
authors.forename: Koji
authors.initials: K
authors.lastname: Sumikawa
authors.forename: Takahito
authors.initials: T
authors.lastname: Kondo
mesh_terms: D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D002104:Cadmium / Q000737:chemistry; D002460:Cell Line; D002470:Cell Survival; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D054477:Glutaredoxins; D005978:Glutathione / Q000737:chemistry; D005980:Glutathione Reductase; D005982:Glutathione Transferase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry; D009249:NADP / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011490:Protein Disulfide Reductase (Glutathione); D017346:Protein Serine-Threonine Kinases; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013880:Thioredoxin-Disulfide Reductase; D013997:Time Factors; D014162:Transfection
chemical_list: D004220:Disulfides; C516007:Glrx protein, rat; D054477:Glutaredoxins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D002104:Cadmium; D009249:NADP; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D007770:L-Lactate Dehydrogenase; D009247:NADH, NADPH Oxidoreductases; D005980:Glutathione Reductase; D013880:Thioredoxin-Disulfide Reductase; C424443:Txnrd3 protein, mouse; D011490:Protein Disulfide Reductase (Glutathione); D005982:Glutathione Transferase; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D005978:Glutathione; D010100:Oxygen