Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
J Biol Chem. 2010 Nov 12;285(46):36138-48. doi: 10.1074/jbc.M110.121202. Epub 2010 Sep 9.
The disulfide relay system of the mitochondrial intermembrane space has been extensively characterized in Saccharomyces cerevisiae. It contains two essential components, Mia40 and Erv1. The genome of Arabidopsis thaliana contains a single gene for each of these components. Although insertional inactivation of Erv1 leads to a lethal phenotype, inactivation of Mia40 results in no detectable deleterious phenotype. A. thaliana Mia40 is targeted to and accumulates in mitochondria and peroxisomes. Inactivation of Mia40 results in an alteration of several proteins in mitochondria, an absence of copper/zinc superoxide dismutase (CSD1), the chaperone for superoxide dismutase (Ccs1) that inserts copper into CSD1, and a decrease in capacity and amount of complex I. In peroxisomes the absence of Mia40 leads to an absence of CSD3 and a decrease in abnormal inflorescence meristem 1 (Aim1), a β-oxidation pathway enzyme. Inactivation of Mia40 leads to an alteration of the transcriptome of A. thaliana, with genes encoding peroxisomal proteins, redox functions, and biotic stress significantly changing in abundance. Thus, the mechanistic operation of the mitochondrial disulfide relay system is different in A. thaliana compared with other systems, and Mia40 has taken on new roles in peroxisomes and mitochondria.
线粒体膜间隙的二硫键中继系统在酿酒酵母中得到了广泛的研究。它包含两个必需的成分，Mia40 和 Erv1。拟南芥的基因组包含这两个成分的单一基因。尽管 Erv1 的插入失活导致致死表型，但 Mia40 的失活不会导致可检测的有害表型。拟南芥 Mia40 靶向并积累在线粒体和过氧化物酶体中。Mia40 的失活导致线粒体中几种蛋白质的改变，铜/锌超氧化物歧化酶（CSD1）缺失，超氧化物歧化酶（Ccs1）的伴侣蛋白插入 CSD1，以及复合物 I 的容量和数量减少。在过氧化物酶体中，Mia40 的缺失导致 CSD3 的缺失和异常花序分生组织 1（Aim1）的减少，Aim1 是一种β-氧化途径的酶。Mia40 的失活导致拟南芥转录组的改变，与过氧化物体蛋白、氧化还原功能和生物胁迫相关的基因丰度显著变化。因此，与其他系统相比，线粒体二硫键中继系统在拟南芥中的作用机制不同，而 Mia40 在过氧化物酶体和线粒体中承担了新的角色。
