Sucrose Starvation Induces Microautophagy in Plant Root Cells
Sucrose Starvation Induces Microautophagy in Plant Root Cells
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DOI：
10.3389/fpls.2019.01604
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发表时间：
2019-12-03
影响因子：
5.6
通讯作者：
Yamada, Kenji
中科院分区：
文献类型：
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作者：
Goto-Yamada, Shino;Oikawa, Kazusato;Yamada, Kenji
自噬是降解和回收细胞成分以在饥饿条件下生存的重要系统。在蔗糖饥饿下，将木瓜蛋白酶抑制剂 E-64d 应用于拟南芥根和烟草 BY-2 细胞，诱导用荧光膜标记 FM4-64 标记的囊泡的积累。在自噬相关基因 ATG2、ATG5 和 ATG7 缺陷的突变体中，E-64d 诱导的囊泡积累减少，表明自噬参与了这些囊泡的形成。为了详细阐明这些囊泡的形成，我们监测了液泡膜随时间的变化，以及蔗糖饥饿细胞中囊泡的积累。我们发现这些囊泡源自液泡膜并通过微自噬过程产生。液泡膜蛋白被排除在囊泡之外，表明囊泡是由特定的膜域产生的。 GFP-ATG8a 转基因植物中的刀那霉素 A 处理表明，并非所有源自液泡膜的 FM4-64 标记的囊泡都含有含有 ATG8a 的结构。这些结果表明 ATG8a 可能并不总是微自噬所必需的。
Autophagy is an essential system for degrading and recycling cellular components for survival during starvation conditions. Under sucrose starvation, application of a papain protease inhibitor E-64d to the Arabidopsis root and tobacco BY-2 cells induced the accumulation of vesicles, labeled with a fluorescent membrane marker FM4-64. The E-64d-induced vesicle accumulation was reduced in the mutant defective in autophagy-related genes ATG2, ATG5, and ATG7, suggesting autophagy is involved in the formation of these vesicles. To clarify the formation of these vesicles in detail, we monitored time-dependent changes of tonoplast, and vesicle accumulation in sucrose-starved cells. We found that these vesicles were derived from the tonoplast and produced by microautophagic process. The tonoplast proteins were excluded from the vesicles, suggesting that the vesicles are generated from specific membrane domains. Concanamycin A treatment in GFP-ATG8a transgenic plants showed that not all FM4-64-labeled vesicles, which were derived from the tonoplast, contained the ATG8a-containing structure. These results suggest that ATG8a may not always be necessary for microautophagy.