Oxidative stress increased respiration and generation of reactive oxygen species, resulting in ATP depletion, opening of mitochondrial permeability transition, and programmed cell death.
Mitochondria constitute a major source of reactive oxygen species and have been proposed to integrate the cellular responses to stress. In animals, it was shown that mitochondria can trigger apoptosis from diverse stimuli through the opening of MTP, which allows the release of the apoptosis-inducing factor and translocation of cytochrome c into the cytosol. Here, we analyzed the role of the mitochondria in the generation of oxidative burst and induction of programmed cell death in response to brief or continuous oxidative stress in Arabidopsis cells. Oxidative stress increased mitochondrial electron transport, resulting in amplification of H(2)O(2) production, depletion of ATP, and cell death. The increased generation of H(2)O(2) also caused the opening of the MTP and the release of cytochrome c from mitochondria. The release of cytochrome c and cell death were prevented by a serine/cysteine protease inhibitor, Pefablock. However, addition of inhibitor only partially inhibited the H(2)O(2) amplification and the MTP opening, suggesting that protease activation is a necessary step in the cell death pathway after mitochondrial damage.
Tiwari
Budhi Sagar
BS
Department of Plant Sciences, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904, Israel.
Belenghi
Beatrice
B
Levine
Alex
A
D000255:Adenosine Triphosphate / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D016572:Cyclosporine / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007425:Intracellular Membranes / Q000502:physiology; D008928:Mitochondria / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010539:Permeability; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013450:Sulfones / Q000494:pharmacology
D003574:Cytochrome c Group; D017382:Reactive Oxygen Species; D015842:Serine Proteinase Inhibitors; D013450:Sulfones; C002010:4-(2-aminoethyl)benzenesulfonylfluoride; D016572:Cyclosporine; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide