线粒体电子传递系统的组装及其生物学意义

电子传递链亦称呼吸链,由位于线粒体内膜的I、II、III、IV 4种复合物组成,负责电子传递和产生质子梯度。电子主要从复合物I进入电子传递链,经复合物III传递至复合物IV。电子传递系统的组装是一个十分复杂的过程,目前已知主要有约69个结构亚基以及至少16个组装因子参与了人类复合物I、III、IV的组装,这些蛋白质由核基因组与线粒体基因组共同编码。对线粒体电子传递系统的蛋白质组成及其结构已研究得较为清楚,但对它们的组装了解得还比较初步。许多人类线粒体疾病是由于电子传递系统的功能障碍引起的,其中又有许多是由于该系统中一个或多个部件的错误组装引起的。研究这些缺陷不仅能够加深对线粒体疾病发病机理的了解,也有助于揭示线粒体功能的调控机制。将着重对电子传递系统复合物的组装及其与人类疾病关系的研究进展进行综述。

The assembly of the mitochondrial electron transport chain system and its biological implications

The mitochondrial electron transport chain（ETC）,or respiration chain,is composed of four respiratory complexes（I,II,III and IV）,which are responsible for electron transfer and generation of the proton gradient across the mitochondrial inner membrane.The majority of electrons enter the respiratory system at complex I,through complex III,and complex IV,and finally deliver to oxygen.The assembly of ETC is a very complicated and intricately regulated process.There are about 69 structural subunits and at least 16 assembly factors,which are encoded by both nuclear and mitochondrial genomes,involved in the assembly of complexes I,III and IV.The protein composition and structure of each complex have been well established,whereas the study of their assembly process just starts.Many human disorders are caused by ETC dysfunction,and many of them are associated with defective assembly of one or more ETC components.The investigation of the assembly ETC is not only useful in understanding the pathogenesis of several mitochondrial disorders,but also important in unraveling the regulatory mechanism of mitochondrial function.Here we will review the current knowledge of the assembly of ETC and its implications in human diseases.