Resolution of oxidative stress by thioredoxin reductase: Cysteine versus selenocysteine.
Resolution of oxidative stress by thioredoxin reductase: Cysteine versus selenocysteine.
复制标题
DOI：
10.1016/j.redox.2014.01.021
复制
发表时间：
2014
期刊：
影响因子：
11.4
通讯作者：
Heintz NH
中科院分区：
文献类型：
--
作者：
Cunniff B;Snider GW;Fredette N;Stumpff J;Hondal RJ;Heintz NH
硫氧还蛋白还原酶（TR）催化硫氧还蛋白（TRX）的还原，其继而还原哺乳动物典型的2-Cys过氧化物氧还蛋白（PRXs 1-4），涉及氧化还原稳态和细胞信号传导的硫醇过氧化物酶。典型的2-Cys PRX通过过氧化半胱氨酸过度氧化为半胱氨酸-亚磺酸而失活，并在两步过程中再生，该两步过程涉及硫氧还蛋白（SRX）的逆还原和TRX的还原。在此，使用瞬时暴露于甲萘醌和葡萄糖氧化酶来检查表达各种TR亚型的小鼠C10细胞中PRX的氧化失活和再活化的动力学，所述TR亚型包括编码硒代半胱氨酸的野生型细胞质TR 1（Sec-TR 1）和线粒体TR 2（Sec-TR 2），以及TR 1和TR 2的突变体，其中硒代半胱氨酸密码子被改变为编码半胱氨酸（Cys-TR 1或Cys-TR 2）。在C10细胞中，内源性TR活性对过氧化氢水平不敏感。Sec-TR 1的表达增加了TR活性，降低了基础细胞质氧化还原状态，并增加了氧化还原响应细胞质GFP探针（roGFP）的还原速率，但不影响PRXs的失活速率或逆向还原速率。与roGFP相比，一旦去除氧化剂，roGFP在几分钟内减少，2-Cys PRX的减少发生在许多小时内。表达野生型Sec-TR 1或Sec-TR 2，而不是Cys-TR 1或TR 2，增加PRX的减少率，并改善甲萘醌暴露后的细胞存活率。这些结果表明，TR的表达水平不降低初始氧化损伤的严重程度，而是控制细胞活力所需的细胞因子的减少速率。由于Sec-TR是完全不敏感的过氧化氢的细胞毒性水平，我们建议TR功能的氧化还原金字塔的顶部，管理氧化还原蛋白和其他蛋白质因子的氧化状态，从而决定了层次结构的表型反应氧化损伤。TR 1和TR 2与PRX对氧化失活的敏感性。Sec与Cys在细胞活力中TR的活性位点中的作用。氧化后与PRX相比roGFP的减少。TR 1和TR 2对细胞区室氧化状态的影响。
Thioredoxin reductase (TR) catalyzes the reduction of thioredoxin (TRX), which in turn reduces mammalian typical 2-Cys peroxiredoxins (PRXs 1–4), thiol peroxidases implicated in redox homeostasis and cell signaling. Typical 2-Cys PRXs are inactivated by hyperoxidation of the peroxidatic cysteine to cysteine-sulfinic acid, and regenerated in a two-step process involving retro-reduction by sulfiredoxin (SRX) and reduction by TRX. Here transient exposure to menadione and glucose oxidase was used to examine the dynamics of oxidative inactivation and reactivation of PRXs in mouse C10 cells expressing various isoforms of TR, including wild type cytoplasmic TR1 (Sec-TR1) and mitochondrial TR2 (Sec-TR2) that encode selenocysteine, as well as mutants of TR1 and TR2 in which the selenocysteine codon was changed to encode cysteine (Cys-TR1 or Cys-TR2). In C10 cells endogenous TR activity was insensitive to levels of hydrogen peroxide that hyperoxidize PRXs. Expression of Sec-TR1 increased TR activity, reduced the basal cytoplasmic redox state, and increased the rate of reduction of a redox-responsive cytoplasmic GFP probe (roGFP), but did not influence either the rate of inactivation or the rate of retro-reduction of PRXs. In comparison to roGFP, which was reduced within minutes once oxidants were removed reduction of 2-Cys PRXs occurred over many hours. Expression of wild type Sec-TR1 or Sec-TR2, but not Cys-TR1 or TR2, increased the rate of reduction of PRXs and improved cell survival after menadione exposure. These results indicate that expression levels of TR do not reduce the severity of initial oxidative insults, but rather govern the rate of reduction of cellular factors required for cell viability. Because Sec-TR is completely insensitive to cytotoxic levels of hydrogen peroxide, we suggest TR functions at the top of a redox pyramid that governs the oxidation state of peroxiredoxins and other protein factors, thereby dictating a hierarchy of phenotypic responses to oxidative insults. Sensitivity of TR1 and TR2 vs. PRXs to oxidative inactivation. Role of Sec vs. Cys in the active site of TR in cell viability. Reduction of roGFP as compared to PRX after oxidation. Effect of TR1 and TR2 on oxidation state of cellular compartments.
登录
查看更多内容
影响因子：
3.7
作者：
Anestål K;Prast-Nielsen S;Cenas N;Arnér ES
通讯作者：
Arnér ES
DOI：
10.1111/j.1742-4658.2009.06985.x
发表时间：
2009-05
期刊：
The FEBS journal
影响因子：
--
作者：
Hall A;Karplus PA;Poole LB
通讯作者：
Poole LB
用于测定细胞裂解物中硫氧还蛋白还原酶活性的直接连续测定。
影响因子：
2.9
作者：
Cunniff B;Snider GW;Fredette N;Hondal RJ;Heintz NH
通讯作者：
Heintz NH
影响因子：
5.6
作者：
Cunniff, Brian;Benson, Kira;Stumpff, Jason;Newick, Kheng;Held, Paul;Taatjes, Douglas;Joseph, Joy;Kalyanaraman, Balaraman;Heintz, Nicholas H.
通讯作者：
Heintz, Nicholas H.
影响因子：
16
作者：
Day, Alison M.;Brown, Jonathon D.;Veal, Elizabeth A.
通讯作者：
Veal, Elizabeth A.