Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
Curr Biol. 2017 Nov 6;27(21):R1177-R1192. doi: 10.1016/j.cub.2017.09.015.
Mitochondria are best known for their role in the generation of ATP by aerobic respiration. Yet, research in the past half century has shown that they perform a much larger suite of functions and that these functions can vary substantially among diverse eukaryotic lineages. Despite this diversity, all mitochondria derive from a common ancestral organelle that originated from the integration of an endosymbiotic alphaproteobacterium into a host cell related to Asgard Archaea. The transition from endosymbiotic bacterium to permanent organelle entailed a massive number of evolutionary changes including the origins of hundreds of new genes and a protein import system, insertion of membrane transporters, integration of metabolism and reproduction, genome reduction, endosymbiotic gene transfer, lateral gene transfer and the retargeting of proteins. These changes occurred incrementally as the endosymbiont and the host became integrated. Although many insights into this transition have been gained, controversy persists regarding the nature of the original endosymbiont, its initial interactions with the host and the timing of its integration relative to the origin of other features of eukaryote cells. Since the establishment of the organelle, proteins have been gained, lost, transferred and retargeted as mitochondria have specialized into the spectrum of functional types seen across the eukaryotic tree of life.
线粒体最广为人知的功能是通过需氧呼吸产生 ATP。然而，在过去的半个世纪的研究表明，它们执行着更多的功能，而且这些功能在不同的真核生物谱系中差异很大。尽管存在这种多样性，但所有的线粒体都来源于一个共同的祖先细胞器，该细胞器起源于一个内共生的α变形菌与古菌相关的宿主细胞的融合。从内共生细菌到永久性细胞器的转变涉及到大量的进化变化，包括数百个新基因和蛋白质导入系统的起源、膜转运蛋白的插入、代谢和繁殖的整合、基因组的减少、内共生基因转移、横向基因转移以及蛋白质的重新靶向。随着共生体和宿主的融合，这些变化逐渐发生。尽管人们对这一转变有了很多了解，但关于原始内共生体的性质、它与宿主的最初相互作用以及它与真核细胞其他特征的起源的相对时间，仍然存在争议。自从细胞器建立以来，随着线粒体专门化到真核生物生命之树中所看到的各种功能类型，蛋白质不断获得、丢失、转移和重新靶向。
