Multiple glutathione disulfide removal pathways mediate cytosolic redox homeostasis
Multiple glutathione disulfide removal pathways mediate cytosolic redox homeostasis
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DOI：
10.1038/nchembio.1142
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发表时间：
2013-02-01
影响因子：
14.8
通讯作者：
Dick, Tobias P.
中科院分区：
文献类型：
--
作者：
Morgan, Bruce;Ezerina, Daria;Dick, Tobias P.
谷氨酸是细胞氧化还原化学的核心。大多数谷胱甘肽氧化还原研究都是基于全细胞提取物的化学分析，这必然会破坏亚细胞区室特异性信息。基于基因编码的荧光探针的隔室特异性实时测量现在表明，细胞溶质谷胱甘肽氧化还原电位比以前认为的还原电位高约100 mV。在酵母中使用这些探针，我们表明，即使在严重的氧化应激，胞质谷胱甘肽二硫化物（GSSG）浓度比预期的更严格的监管，并提供了一个机制解释与传统测量的差异。GSSG在胞质溶胶中不立即被还原，通过ABC-C转运蛋白Ycf 1快速转运到液泡中。全细胞GSSG的量完全依赖于Ycf 1，并且无法提供有关胞浆谷胱甘肽池的信息。应用这些见解，我们确定Trx 2和Grx 2作为谷胱甘肽还原酶的有效备份系统，用于细胞溶质GSSG还原。
Glutathione is central to cellular redox chemistry. The majority of glutathione redox research has been based on the chemical analysis of whole-cell extracts, which unavoidably destroy subcellular compartment-specific information. Compartment-specific real-time measurements based on genetically encoded fluorescent probes now suggest that the cytosolic glutathione redox potential is about 100 mV more reducing than previously thought. Using these probes in yeast, we show that even during severe oxidative stress, the cytosolic glutathione disulfide (GSSG) concentration is much more tightly regulated than expected and provide a mechanistic explanation for the discrepancy with conventional measurements. GSSG that is not immediately reduced in the cytosol is rapidly transported into the vacuole by the ABC-C transporter Ycf1. The amount of whole-cell GSSG is entirely dependent on Ycf1 and uninformative about the cytosolic glutathione pool. Applying these insights, we identify Trx2 and Grx2 as efficient backup systems to glutathione reductase for cytosolic GSSG reduction.