Laboratory of Molecular Plant Physiology, Department of Experimental Evolutionary Biology, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
Plant Sci. 2012 Apr;185-186:86-96. doi: 10.1016/j.plantsci.2012.01.005. Epub 2012 Jan 23.
Reactive oxygen species play important roles in redox signaling mainly through a set of reversible post-translational modifications of cysteine thiol residues in proteins, including glutathionylation and dithiol/disulfide exchange. Protein glutathionylation has been extensively studied in mammals but emerging evidence suggests that it can play important roles in plants and in chloroplast in particular. This redox modification involves protein thiols and glutathione and is mainly controlled by glutaredoxins, oxidoreductases belonging to the thioredoxin superfamily. In this review, we first present the possible mechanisms of protein glutathionylation and then introduce the chloroplast systems of glutaredoxins and thioredoxins, in order to pinpoint the biochemical properties that make some glutaredoxin isoforms the master enzymes in deglutathionylation. Finally, we discuss the possible roles of glutathionylation in thiol protection, protein regulation, reactive oxygen species scavenging and redox signaling in chloroplasts, with emphasis on the crosstalk between thioredoxin- and glutaredoxin-mediated signaling pathways.
活性氧在氧化还原信号中起着重要作用，主要通过蛋白质半胱氨酸巯基残基的一系列可逆翻译后修饰来实现，包括谷胱甘肽化和二硫键/巯基交换。蛋白质谷胱甘肽化在哺乳动物中得到了广泛研究，但新出现的证据表明，它在植物，特别是在叶绿体中可以发挥重要作用。这种氧化还原修饰涉及蛋白质巯基和谷胱甘肽，主要由谷氧还蛋白控制，谷氧还蛋白属于硫氧还蛋白超家族的氧化还原酶。在这篇综述中，我们首先介绍了蛋白质谷胱甘肽化的可能机制，然后介绍了叶绿体中的谷氧还蛋白和硫氧还蛋白系统，以确定使某些谷氧还蛋白同工酶成为去谷胱甘肽化主酶的生化特性。最后，我们讨论了谷胱甘肽化在叶绿体中巯基保护、蛋白质调节、活性氧清除和氧化还原信号中的可能作用，重点讨论了硫氧还蛋白和谷氧还蛋白介导的信号通路之间的串扰。
