Singlet oxygen- and EXECUTER1-mediated signaling is initiated in grana margins and depends on the protease FtsH2
Singlet oxygen- and EXECUTER1-mediated signaling is initiated in grana margins and depends on the protease FtsH2
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DOI：
10.1073/pnas.1603562113
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发表时间：
2016-06-28
影响因子：
11.1
通讯作者：
Apel, Klaus
中科院分区：
文献类型：
--
作者：
Wang, Liangsheng;Kim, Chanhong;Apel, Klaus
单线态氧 (O-1(2)) 的形成与光系统 II (PSII) 的破坏有关，光系统 II (PSII) 需要进行持续修复以维持光合电子传输。除了其破坏作用外，O-1(2) 还被证明可以充当触发应激适应和增强应激抵抗力的信号。 O-1(2) 的信号传导作用首次在拟南芥荧光 (flu) 突变体中被记录。它严格依赖于叶绿体蛋白 EXECUTER1 (EX1)，并在非光抑制光照条件下发生。在严重的光胁迫下，信号传导是由 O-1(2) 独立于 EX1 启动的，O-1(2) 被认为是在基粒堆叠核心内的活性 PSII 的受体侧产生的。本研究的结果表明 O-1(2) 形成的第二个来源是靠近叶绿素合成位点的基粒边缘，EX1 位于此处，并且发生受损的分解和活性 PSII 的重新组装。基粒边缘 O-1(2) 信号传导的启动取决于 EX1 和 ATP 依赖性锌金属蛋白酶 FtsH。由于 FtsH 在受损 PSII 分解过程中也会裂解 D1 蛋白，因此 EX1 和 O-1(2) 介导的信号传导似乎不仅在空间上而且在功能上与 PSII 的修复相关。
Formation of singlet oxygen (O-1(2)) has been implicated with damaging photosystem II (PSII) that needs to undergo continuous repair to maintain photosynthetic electron transport. In addition to its damaging effect, O-1(2) has also been shown to act as a signal that triggers stress acclimation and an enhanced stress resistance. A signaling role of O-1(2) was first documented in the fluorescent (flu) mutant of Arabidopsis. It strictly depends on the chloroplast protein EXECUTER1 (EX1) and happens under nonphotoinhibitory light conditions. Under severe light stress, signaling is initiated independently of EX1 by O-1(2) that is thought to be generated at the acceptor side of active PSII within the core of grana stacks. The results of the present study suggest a second source of O-1(2) formation in grana margins close to the site of chlorophyll synthesis where EX1 is localized and the disassembly of damaged and reassembly of active PSII take place. The initiation of O-1(2) signaling in grana margins depends on EX1 and the ATP-dependent zinc metalloprotease FtsH. As FtsH cleaves also the D1 protein during the disassembly of damaged PSII, EX1- and O-1(2)-mediated signaling seems to be not only spatially but also functionally associated with the repair of PSII.