Role of Lon1 protease in post-germinative growth and maintenance of mitochondrial function in Arabidopsis thaliana.
Role of Lon1 protease in post-germinative growth and maintenance of mitochondrial function in Arabidopsis thaliana.
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DOI：
10.1111/j.1469-8137.2008.02701.x
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发表时间：
2009-02
期刊：
影响因子：
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通讯作者：
Stamatis Rigas;G. Daras;Miriam Laxa;Nikolas Marathias;C. Fasseas;L. Sweetlove;P. Hatzopoulos
中科院分区：
文献类型：
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作者：
Stamatis Rigas;G. Daras;Miriam Laxa;Nikolas Marathias;C. Fasseas;L. Sweetlove;P. Hatzopoulos
维持蛋白质的质量控制和周转对细胞内环境的稳定至关重要。在植物细胞器中，这一生物过程主要由依赖于ATP的蛋白水解酶完成。在这里，进行了遗传筛选，从而鉴定了表现胚胎后生长迟缓表型的拟南芥Lon1蛋白水解酶突变体。与黄色荧光蛋白的翻译融合显示，AtLon1基因在植物线粒体中定位于亚细胞内，AtLon1基因可以补充酵母PIM1基因同源物的呼吸缺陷表型。AtLon1在快速生长的植物胚性器官中高度表达，包括子叶和初级根，以及花序，这增加了每个细胞的线粒体数量，以满足它们的高能量需求。在Lon1突变体中，线粒体和核基因编码呼吸蛋白的表达都是正常的。然而，从Lon1突变体分离的线粒体分别通过复合体II和IV呼吸琥珀酸和细胞色素c的能力较低。此外，三羧酸(TCA)循环的关键酶活性显著降低。此外，Lon1突变体的线粒体具有异常的形态。这些结果揭示了植物线粒体选择性蛋白分解的发育机制，并表明AtLon1蛋白在细胞器生物发生和幼苗建立中起着关键作用。
Maintenance of protein quality control and turnover is essential for cellular homeostasis. In plant organelles this biological process is predominantly performed by ATP-dependent proteases. Here, a genetic screen was performed that led to the identification of Arabidopsis thaliana Lon1 protease mutants that exhibit a post-embryonic growth retardation phenotype. Translational fusion to yellow fluorescent protein revealed AtLon1 subcellular localization in plant mitochondria, and the AtLon1 gene could complement the respiratory-deficient phenotype of the yeast PIM1 gene homolog. AtLon1 is highly expressed in rapidly growing plant organs of embryonic origin, including cotyledons and primary roots, and in inflorescences, which have increased mitochondria numbers per cell to fulfill their high energy requirements. In lon1 mutants, the expression of both mitochondrial and nuclear genes encoding respiratory proteins was normal. However, mitochondria isolated from lon1 mutants had a lower capacity for respiration of succinate and cytochrome c via complexes II and IV, respectively. Furthermore, the activity of key enzymes of the tricarboxylic acid (TCA) cycle was significantly reduced. Additionally, mitochondria in lon1 mutants had an aberrant morphology. These results shed light on the developmental mechanisms of selective proteolysis in plant mitochondria and suggest a critical role for AtLon1 protease in organelle biogenesis and seedling establishment.