Glutaredoxin 2 catalyzes the reversible oxidation and glutathionylation of mitochondrial membrane thiol proteins - Implications for mitochondrial redox regulation and antioxidant defense
Glutaredoxin 2 catalyzes the reversible oxidation and glutathionylation of mitochondrial membrane thiol proteins - Implications for mitochondrial redox regulation and antioxidant defense
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DOI：
10.1074/jbc.m408011200
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发表时间：
2004-11-12
影响因子：
4.8
通讯作者：
Murphy, MP
中科院分区：
文献类型：
--
作者：
Beer, SM;Taylor, ER;Murphy, MP
线粒体谷胱甘肽池的氧化还原平衡在线粒体对氧化损伤和氧化还原信号的响应中起着重要作用，但其机制尚不确定。一种可能性是谷胱甘肽（GSH）氧化为谷胱甘肽二硫化物（GSSG）以及GSH/GSSG比例的随之变化导致蛋白质硫醇改变其氧化还原状态，使蛋白质功能能够可逆地响应氧化还原信号和氧化损伤。然而，很少有人知道线粒体谷胱甘肽池和蛋白质巯基之间的相互作用。因此，我们研究了生理GSH/GSSG比例如何影响线粒体膜蛋白巯基的氧化还原状态。暴露于氧化GSH/GSSG比率导致反应性蛋白硫醇通过硫醇-二硫键交换可逆氧化，其程度取决于GSH/GSSG比率。有一个初始的快速阶段的蛋白质巯基氧化，然后逐渐氧化超过30分钟。大量的线粒体蛋白含有活性巯基，其中大部分形成蛋白内二硫化物氧化后，由GSSG，但是，少数形成持久的混合二硫化物与谷胱甘肽。蛋白质二硫键形成和谷胱甘肽化都由线粒体巯基转移酶谷氧还蛋白2（Grx 2）催化，蛋白质脱谷胱甘肽化和还原蛋白质二硫键由GSH催化。复合物I是最突出的蛋白质，其在Grx 2存在下被GSSG持续谷胱甘肽化。维持复合物I与氧化的GSH/GSSG的比例导致了显着的活性损失，这表明线粒体谷胱甘肽池的氧化可能有助于选择性复合物I在帕金森氏病中看到的失活。最重要的是，Grx 2催化可逆的蛋白质谷胱甘肽化/脱谷胱甘肽在广泛的GSH/GSSG的比例，从氧化还原信号下的还原水平，只有在严重的氧化应激下发现的氧化比。我们的研究结果表明，Grx 2通过促进线粒体谷胱甘肽池和蛋白硫醇之间的相互作用，在线粒体对氧化还原信号和氧化应激的响应中起着核心作用。
The redox poise of the mitochondrial glutathione pool is central in the response of mitochondria to oxidative damage and redox signaling, but the mechanisms are uncertain. One possibility is that the oxidation of glutathione (GSH) to glutathione disulfide (GSSG) and the consequent change in the GSH/GSSG ratio causes protein thiols to change their redox state, enabling protein function to respond reversibly to redox signals and oxidative damage. However, little is known about the interplay between the mitochondrial glutathione pool and protein thiols. Therefore we investigated how physiological GSH/GSSG ratios affected the redox state of mitochondrial membrane protein thiols. Exposure to oxidized GSH/GSSG ratios led to the reversible oxidation of reactive protein thiols by thiol-disulfide exchange, the extent of which was dependent on the GSH/GSSG ratio. There was an initial rapid phase of protein thiol oxidation, followed by gradual oxidation over 30 min. A large number of mitochondrial proteins contain reactive thiols and most of these formed intraprotein disulfides upon oxidation by GSSG; however, a small number formed persistent mixed disulfides with glutathione. Both protein disulfide formation and glutathionylation were catalyzed by the mitochondrial thiol transferase glutaredoxin 2 (Grx2), as were protein deglutathionylation and the reduction of protein disulfides by GSH. Complex I was the most prominent protein that was persistently glutathionylated by GSSG in the presence of Grx2. Maintenance of complex I with an oxidized GSH/GSSG ratio led to a dramatic loss of activity, suggesting that oxidation of the mitochondrial glutathione pool may contribute to the selective complex I inactivation seen in Parkinson's disease. Most significantly, Grx2 catalyzed reversible protein glutathionylation/deglutathionylation over a wide range of GSH/GSSG ratios, from the reduced levels accessible under redox signaling to oxidized ratios only found under severe oxidative stress. Our findings indicate that Grx2 plays a central role in the response of mitochondria to both redox signals and oxidative stress by facilitating the interplay between the mitochondrial glutathione pool and protein thiols.