Munich Center for Integrated Protein Science CiPS(M-), Ludwig-Maximilians-Universität München, Munich, Germany.
Plant Signal Behav. 2010 Feb;5(2):105-9. doi: 10.4161/psb.5.2.10525. Epub 2010 Feb 4.
Redox signals play important roles in many developmental and metabolic processes, in particular in chloroplasts and mitochondria. Furthermore, redox reactions are crucial for protein folding via the formation of inter- or intramolecular disulfide bridges. Recently, redox signals were described to be additionally involved in regulation of protein import: in mitochondria, a disulfide relay system mediates retention of cystein-rich proteins in the intermembrane space by oxidizing them. Two essential proteins, the redox-activated receptor Mia40 and the sulfhydryl oxidase Erv1 participate in this pathway. In chloroplasts, it becomes apparent that protein import is affected by redox signals on both the outer and inner envelope: at the level of the Toc complex (translocon at the outer envelope of chloroplasts), the formation/reduction of disulfide bridges between the Toc components has a strong influence on import yield. Moreover, the stromal metabolic redox state seems to be sensed by the Tic complex (translocon at the inner envelope of chloroplasts) that is able to adjust translocation efficiency of a subgroup of redox-related preproteins accordingly. This review summarizes the current knowledge of these redox-regulatory pathways and focuses on similarities and differences between chloroplasts and mitochondria.
氧化还原信号在许多发育和代谢过程中发挥重要作用，特别是在叶绿体和线粒体中。此外，氧化还原反应对于通过形成分子内或分子间二硫键来进行蛋白质折叠至关重要。最近，氧化还原信号被描述为另外参与蛋白质导入的调节：在线粒体中，一个二硫键中继系统通过氧化将富含半胱氨酸的蛋白质保留在膜间隙中。两个必需的蛋白质，即氧化还原激活受体 Mia40 和硫氧还蛋白 Erv1，参与了这一途径。在叶绿体中，很明显，蛋白质导入受到外膜和内膜上氧化还原信号的影响：在Toc 复合物（叶绿体外膜的转运体）水平上，Toc 成分之间二硫键的形成/还原对导入效率有很大影响。此外，基质代谢氧化还原状态似乎被 Tic 复合物（叶绿体的内膜转运体）感知，后者能够相应地调节一组与氧化还原相关的前体蛋白的易位效率。这篇综述总结了这些氧化还原调节途径的最新知识，并重点关注了叶绿体和线粒体之间的相似性和差异。
