title: Separation of cytochrome c-dependent caspase activation from thiol-disulfide redox change in cells lacking mitochondrial DNA.
abstract: Release of mitochondrial cytochrome c (cyt c) is an early and common event during apoptosis. Previous studies showed that the loss of cyt c triggered superoxide production by mitochondria and contributed to the oxidation of cellular thiol-disulfide redox state. In this study, we tested whether loss of the functional electron transport chain due to depleting mitochondrial DNA (mtDNA) would affect this redox-signaling mechanism during apoptosis. Results showed that cyt c release and caspase activation in response to staurosporine treatment were preserved in cells lacking mitochondrial DNA (rho0 cells). However, unlike the case with rho+ cells, in which a dramatic oxidation of intracellular glutathione (GSH) occurred after mitochondrial cyt c release, the thiol-disulfide redox state in apoptotic rho0 cells remained largely unchanged. Thus, mitochondrial signaling of caspase activation can be separated from the bioenergetic function, and mitochondrial respiratory chain is the principal source of ROS generation in staurosporine-induced apoptosis.
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: J
authors.initials: J
authors.lastname: Cai
authors.forename: D C
authors.initials: DC
authors.lastname: Wallace
authors.forename: B
authors.initials: B
authors.lastname: Zhivotovsky
authors.forename: D P
authors.initials: DP
authors.lastname: Jones
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism*; D002460:Cell Line; D003574:Cytochrome c Group / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004272:DNA, Mitochondrial / Q000235:genetics*; D004220:Disulfides / Q000378:metabolism*; D004579:Electron Transport / Q000502:physiology; D004789:Enzyme Activation; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D019169:Jurkat Cells; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine / Q000494:pharmacology; D019014:fas Receptor / Q000378:metabolism
chemical_list: D003574:Cytochrome c Group; D004272:DNA, Mitochondrial; D004220:Disulfides; D017382:Reactive Oxygen Species; D019014:fas Receptor; D000263:Adenylate Kinase; D020169:Caspases; D005978:Glutathione; D019311:Staurosporine; D019803:Glutathione Disulfide