Regulation of apoptosis by Bcl-2 cysteine oxidation in human lung epithelial cells.
Hydrogen peroxide is a key mediator of oxidative stress known to be important in various cellular processes, including apoptosis. B-cell lymphoma-2 (Bcl-2) is an oxidative stress-responsive protein and a key regulator of apoptosis; however, the underlying mechanisms of oxidative regulation of Bcl-2 are not well understood. The present study investigates the direct effect of H2O2 on Bcl-2 cysteine oxidation as a potential mechanism of apoptosis regulation. Exposure of human lung epithelial cells to H2O2 induces apoptosis concomitant with cysteine oxidation and down-regulation of Bcl-2. Inhibition of Bcl-2 oxidation by antioxidants or by site-directed mutagenesis of Bcl-2 at Cys-158 and Cys-229 abrogates the effects of H2O2 on Bcl-2 and apoptosis. Immunoprecipitation and confocal microscopic studies show that Bcl-2 interacts with mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2 [ERK1/2]) to suppress apoptosis and that this interaction is modulated by cysteine oxidation of Bcl-2. The H2O2-induced Bcl-2 cysteine oxidation interferes with Bcl-2 and ERK1/2 interaction. Mutation of the cysteine residues inhibits the disruption of Bcl-2-ERK complex, as well as the induction of apoptosis by H2O2. Taken together, these results demonstrate the critical role of Bcl-2 cysteine oxidation in the regulation of apoptosis through ERK signaling. This new finding reveals crucial redox regulatory mechanisms that control the antiapoptotic function of Bcl-2.
Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506, USA.
Sudjit
S
Luanpitpong
Pithi
P
Chanvorachote
Christian
C
Stehlik
William
W
Tse
Patrick S
PS
Callery
Liying
L
Wang
Yon
Y
Rojanasakul
D000111:Acetylcysteine / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002374:Catalase / Q000378:metabolism; D002460:Cell Line; D003545:Cysteine / Q000378:metabolism*; D015536:Down-Regulation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D008168:Lung / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009154:Mutation; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D000975:Antioxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase; D048049:Extracellular Signal-Regulated MAP Kinases; D005978:Glutathione; D003545:Cysteine; D000111:Acetylcysteine