Chloroplasts are partially mobilized to the vacuole by autophagy
Chloroplasts are partially mobilized to the vacuole by autophagy
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DOI：
10.4161/auto.6804
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发表时间：
2008-10-01
期刊：
影响因子：
13.3
通讯作者：
Yoshimoto, Kohki
中科院分区：
文献类型：
--
作者：
Ishida, Hiroyuki;Yoshimoto, Kohki
除中央液泡外，叶绿体构成植物叶细胞内最大的区室，约占叶总氮的 80%，主要以蛋白质形式存在。大部分氮被分配给光合作用中的固碳酶 Rubisco。在衰老过程中，植物可以将老叶叶绿体中的氮转移到其他器官，例如正在发育的种子。尽管植物中细胞质和细胞器的大量降解是通过自噬发生的，但自噬在叶绿体蛋白降解中的作用仍不清楚。我们最近证明，基质靶向的绿色荧光蛋白 (GFP)、DsRed 和 GFP 标记的 Rubisco 可以通过含有 Rubisco 的小体以 ATG 基因依赖性方式动员到活细胞的液泡中。我们的结果表明叶绿体基质蛋白存在特定的自噬途径，该途径不会导致叶绿体裂解。在这里，我们还讨论了基质填充的小管、基质对基质蛋白自噬转移到液泡的影响，这对于细胞器的结构灵活性很重要。
Excluding the central vacuole, chloroplasts constitute the largest compartment within the leaf cells of plants and contain approximately 80 percent of the total leaf nitrogen, mainly as proteins. Much of this nitrogen is allocated to the carbon-fixing enzyme in photosynthesis, Rubisco. During senescence, plants can mobilize nitrogen from chloroplasts in older leaves to other organs, such as developing seeds. Whereas bulk degradation of the cytosol and organelles in plants occurs by autophagy, the role of autophagy in the degradation of chloroplast proteins is still unclear. We have recently demonstrated that stroma-targeted green fluorescent protein (GFP), DsRed, and GFP-labeled Rubisco can be mobilized to the vacuole of living cells via Rubisco-containing bodies, in an ATG gene-dependent manner. Our results indicate the presence of a specific autophagic pathway for chloroplast stromal proteins, which does not cause chloroplast lysis. Here, we also discuss the involvement of stroma-filled tubules, stromules, which are important for the structural flexibility of the organelle, on the autophagic transfer of stromal proteins to the vacuole.