Garmier Marie, Carroll Adam J, Delannoy Etienne, Vallet Corinne, Day David A, Small Ian D, Millar A Harvey
Australian Research Council Centre of Excellence in Plant Energy Biology M316, University of Western Australia, Crawley, Western Australia 6009, Australia.
Plant Physiol. 2008 Nov;148(3):1324-41. doi: 10.1104/pp.108.125880. Epub 2008 Sep 10.
Mitochondrial complex I is a major avenue for reduced NAD oxidation linked to oxidative phosphorylation in plants. However, the plant enzyme has structural and functional features that set it apart from its counterparts in other organisms, raising questions about the physiological significance of this complex in plants. We have developed an experimental model in which rotenone, a classic complex I inhibitor, has been applied to Arabidopsis (Arabidopsis thaliana) cell suspension cultures in order to dissect early metabolic adjustments involved in cell acclimation to mitochondrial dysfunction. Rotenone induced a transitory decrease in cellular respiration (0-4 h after treatment). Cell respiration then progressively recovered and reached a steady state at 10 to 12 h after treatment. Complex I inhibition by rotenone did not induce obvious oxidative stress or cell death but affected longer term cell growth. Integrated analyses of gene expression, the mitochondrial proteome, and changes in primary metabolism indicated that rotenone treatment caused changes in mitochondrial function via alterations in specific components. A physical disengagement of glycolytic activities associated with the mitochondrial outer membrane was observed, and the tricarboxylic acid cycle was altered. Amino acid and organic acid pools were also modified by rotenone treatment, with a marked early decrease of 2-oxoglutarate, aspartate, and glutamine pools. These data demonstrate that, in Arabidopsis cells, complex I inhibition by rotenone induces significant remodeling of metabolic pathways involving the mitochondria and other compartments and point to early metabolic changes in response to mitochondrial dysfunction.
线粒体复合物I是植物中与氧化磷酸化相关的还原型NAD氧化的主要途径。然而，植物中的这种酶具有一些结构和功能特征，使其有别于其他生物中的同类酶，这引发了关于该复合物在植物中的生理意义的疑问。我们构建了一个实验模型，其中将经典的复合物I抑制剂鱼藤酮应用于拟南芥（Arabidopsis thaliana）细胞悬浮培养物，以剖析细胞适应线粒体功能障碍所涉及的早期代谢调整。鱼藤酮诱导细胞呼吸出现短暂下降（处理后0 - 4小时）。然后细胞呼吸逐渐恢复，并在处理后10至12小时达到稳定状态。鱼藤酮对复合物I的抑制并未诱导明显的氧化应激或细胞死亡，但影响了细胞的长期生长。对基因表达、线粒体蛋白质组以及初级代谢变化的综合分析表明，鱼藤酮处理通过特定成分的改变导致线粒体功能发生变化。观察到与线粒体外膜相关的糖酵解活性发生了物理分离，三羧酸循环也发生了改变。鱼藤酮处理还改变了氨基酸和有机酸库，2-氧代戊二酸、天冬氨酸和谷氨酰胺库在早期显著减少。这些数据表明，在拟南芥细胞中，鱼藤酮对复合物I的抑制会诱导涉及线粒体和其他区室的代谢途径发生显著重塑，并指出了对线粒体功能障碍的早期代谢变化。
