High Light Intensity Leads to Increased Peroxule-Mitochondria Interactions in Plants.
High Light Intensity Leads to Increased Peroxule-Mitochondria Interactions in Plants.
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DOI：
10.3389/fcell.2016.00006
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发表时间：
2016
影响因子：
5.5
通讯作者：
Mathur J
中科院分区：
文献类型：
--
作者：
Jaipargas EA;Mathur N;Bou Daher F;Wasteneys GO;Mathur J
过氧化物是球形过氧化物酶体在低水平活性氧（ROS）胁迫下产生的薄突起。然而，应力缓解有利于过氧化物酶体收缩，ROS应力的延长导致过氧化物酶体伸长成管状。随后，通过与动力蛋白相关蛋白3A和3B等蛋白的结合，延长的形式变得狭窄，并最终发生裂变，增加细胞内的过氧化物酶体数量。在活的植物细胞中尚未观察到在过氧化物酶起始和整个过氧化物酶体形成管状之间的短时间窗口内发生的事件。在这里，使用荧光蛋白辅助实时成像，我们发现在高光（HL）照射仅4分钟后就形成了过氧化物，在此期间，细胞质中过氧化氢的水平明显增加。利用一个稳定的双转基因拟南芥系，表达过氧化物酶体靶向YFP和线粒体靶向GFP探针，我们观察到过氧化物和小球形线粒体之间持续的相互作用。此外，我们观察到，在拟南芥各向异性1突变体中，hl诱导的过氧化物和线粒体之间的相互作用频率增加，这降低了细胞壁的结晶度，并且我们发现比野生型植物积累了更高的H2O2水平。我们的观察结果提出了一个可测试的模型，其中过氧化物作为ros受损线粒体的相互作用平台，可能释放膜蛋白和裂变因子。因此，这些蛋白质很容易被过氧化物酶体利用，并促进它们的增殖，从而增强植物细胞抗ros的能力。
Peroxules are thin protrusions from spherical peroxisomes produced under low levels of reactive oxygen species (ROS) stress. Whereas, stress mitigation favors peroxule retraction, prolongation of the ROS stress leads to the elongation of the peroxisome into a tubular form. Subsequently, the elongated form becomes constricted through the binding of proteins such as dynamin related proteins 3A and 3B and eventually undergoes fission to increase the peroxisomal population within a cell. The events that occur in the short time window between peroxule initiation and the tubulation of the entire peroxisome have not been observed in living plant cells. Here, using fluorescent protein aided live-imaging, we show that peroxules are formed after only 4 min of high light (HL) irradiation during which there is a perceptible increase in the cytosolic levels of hydrogen peroxide. Using a stable, double transgenic line of Arabidopsis thaliana expressing a peroxisome targeted YFP and a mitochondrial targeted GFP probe, we observed sustained interactions between peroxules and small, spherical mitochondria. Further, it was observed that the frequency of HL-induced interactions between peroxules and mitochondria increased in the Arabidopsis anisotropy1 mutant that has reduced cell wall crystallinity and where we show accumulation of higher H2O2 levels than wild type plants. Our observations suggest a testable model whereby peroxules act as interaction platforms for ROS-distressed mitochondria that may release membrane proteins and fission factors. These proteins might thus become easily available to peroxisomes and facilitate their proliferation for enhancing the ROS-combating capability of a plant cell.