Reactive Carbonyl Species Activate Caspase-3-Like Protease to Initiate Programmed Cell Death in Plants.
Reactive oxygen species (ROS)-triggered programmed cell death (PCD) is a typical plant response to biotic and abiotic stressors. We have recently shown that lipid peroxide-derived reactive carbonyl species (RCS), downstream products of ROS, mediate oxidative signal to initiate PCD. Here we investigated the mechanism by which RCS initiate PCD. Tobacco Bright Yellow-2 cultured cells were treated with acrolein, one of the most potent RCS. Acrolein at 0.2 mM caused PCD in 5 h (i.e. lethal), but at 0.1 mM it did not (sublethal). Specifically, these two doses caused critically different effects on the cells. Both lethal and sublethal doses of acrolein exhausted the cellular glutathione pool in 30 min, while the lethal dose only caused a significant ascorbate decrease and ROS increase in 1-2 h. Prior to such redox changes, we found that acrolein caused significant increases in the activities of caspase-1-like protease (C1LP) and caspase-3-like protease (C3LP), the proteases which trigger PCD. The lethal dose of acrolein increased the C3LP activity 2-fold more than did the sublethal dose. In contrast, C1LP activity increments caused by the two doses were not different. Acrolein and 4-hydroxy-(E)-2-nonenal, another RCS, activated both proteases in a cell-free extract from untreated cells. H2O2at 1 mM added to the cells increased C1LP and C3LP activities and caused PCD, and the RCS scavenger carnosine suppressed their activation and PCD. However, H2O2did not activate the proteases in a cell-free extract. Thus the activation of caspase-like proteases, particularly C3LP, by RCS is an initial biochemical event in oxidative signal-stimulated PCD in plants.
The United Graduate School of Agriculture, Tottori University, Koyama-Cho Minami 4-101, Tottori, 680-8550 Japan.|Department of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh.
Md Sanaullah
MS
Biswas
The United Graduate School of Agriculture, Tottori University, Koyama-Cho Minami 4-101, Tottori, 680-8550 Japan mano@yamaguchi-u.ac.jp.|Science Research Center, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515 Japan.|Graduate School of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515 Japan.
Jun'ichi
J
Mano
D000171:Acrolein / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001205:Ascorbic Acid / Q000378:metabolism; D002336:Carnosine / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002474:Cell-Free System; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000633:toxicity; D042541:Intracellular Space / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D059828:Plant Cells / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014026:Nicotiana / Q000166:cytology* / Q000187:drug effects / Q000235:genetics
D016166:Free Radical Scavengers; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D000171:Acrolein; D002336:Carnosine; D006861:Hydrogen Peroxide; D053148:Caspase 3; D005978:Glutathione; D001205:Ascorbic Acid
20S proteasome; Caspase-like-protease; Oxidative signal; Oxylipin carbonyls; Reactive electrophile species; Vacuolar processing enzyme