Glutathionylation of beta-actin via a cysteinyl sulfenic acid intermediary.
Glutathionylation of beta-actin via a cysteinyl sulfenic acid intermediary.
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DOI：
10.1186/1471-2091-8-26
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发表时间：
2007-12-10
期刊：
影响因子：
--
通讯作者：
Lundberg M
中科院分区：
文献类型：
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作者：
Johansson M;Lundberg M
肌动蛋白中的半胱氨酸残基是谷胱甘肽化的，即。与谷胱甘肽形成混合二硫化物，即使在没有外源性氧化应激的情况下。谷胱甘肽化抑制肌动蛋白聚合，而可逆的肌动蛋白谷胱甘肽化是调节细胞骨架结构的氧化还原依赖性机制。体内介导肌动蛋白谷胱甘肽化的分子机制尚不清楚。我们研究了谷胱甘肽的α-和β-肌动蛋白在体外使用酶联免疫吸附试验与单克隆抗谷胱甘肽抗体。α-肌动蛋白和β-肌动蛋白在与还原型谷胱甘肽（GSH）结合二酰胺作为巯基氧化剂孵育时都被谷胱甘肽化。然而，β-肌动蛋白也被谷胱甘肽二硫化物（GSSG）和GSH在没有二酰胺的情况下谷胱甘肽化，而α-肌动蛋白很少被GSH或GSSG谷胱甘肽化。GSSG对β-肌动蛋白的谷胱甘肽化可能通过巯基交换机制介导，而GSH对β-肌动蛋白的谷胱甘肽化需要巯基氧化。GSH对β-actin谷胱甘肽化的抑制作用可被亚砷酸盐和二甲双胍抑制，提示其机制与β-actin中半胱氨酰次磺酸残基的形成有关。我们得出结论，β-肌动蛋白的谷胱甘肽化可能通过半胱氨酰残基自发氧化为亚磺酸而发生，亚磺酸易于与GSH反应形成混合二硫化物。我们还表明，不同的肌动蛋白亚型之间的反应性和氧化反应蛋白巯基中间体不同。
Cysteinyl residues in actin are glutathionylated, ie. form a mixed disulfide with glutathione, even in the absence of exogenous oxidative stress. Glutathionylation inhibits actin polymerization and reversible actin glutathionylation is a redox dependent mechanism for regulation of the cytoskeleton structure. The molecular mechanism that mediates actin glutathionylation in vivo is unclear. We have studied glutathionylation of α- and β-actin in vitro using an enzyme-linked immunosorbant assay with a monoclonal anti-glutathione antibody. α- and β-actin were both glutathionylated when incubated with reduced glutathione (GSH) combined with diamide as a thiol oxidant. However, β-actin was also glutathionylated by both glutathione disulfide (GSSG) and GSH in the absence of diamide whereas α-actin was poorly glutathionylated by GSH or GSSG. Glutathionylation of β-actin by GSSG is likely to be mediated by a thiol-exchange mechanism whereas glutathionylation by GSH requires thiol oxidation. β-actin glutathionylation by GSH was inhibited by arsenite and dimedone suggesting that the mechanism involved formation of a cysteinyl sulfenic acid residue in β-actin. We conclude that glutathionylation of β-actin may occur via spontaneous oxidation of a cysteinyl residue to a sulfenic acid that readily reacts with GSH to form a mixed disulfide. We also show that the reactivity and oxidation to a reactive protein thiol intermediary differ between different actin isoforms.