Institute for Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany.
Institute for Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany.
Trends Microbiol. 2016 Jul;24(7):525-534. doi: 10.1016/j.tim.2016.03.005. Epub 2016 Mar 31.
Eukaryotes possess an elaborate endomembrane system with endoplasmic reticulum, nucleus, Golgi, lysosomes, peroxisomes, autophagosomes, and dynamic vesicle traffic. Theories addressing the evolutionary origin of eukaryotic endomembranes have overlooked the outer membrane vesicles (OMVs) that bacteria, archaea, and mitochondria secrete into their surroundings. We propose that the eukaryotic endomembrane system originated from bacterial OMVs released by the mitochondrial ancestor within the cytosol of its archaeal host at eukaryote origin. Confined within the host's cytosol, OMVs accumulated naturally, fusing either with each other or with the host's plasma membrane. This matched the host's archaeal secretory pathway for cotranslational protein insertion with outward bound mitochondrial-derived vesicles consisting of bacterial lipids, forging a primordial, secretory endoplasmic reticulum as the cornerstone of the eukaryotic endomembrane system. VIDEO ABSTRACT.
真核生物拥有一套精细的内膜系统，包括内质网、核、高尔基体、溶酶体、过氧化物酶体、自噬体和动态囊泡运输。然而，关于真核生物内膜系统进化起源的理论却忽视了细菌、古菌和线粒体分泌到周围环境中的外膜囊泡（OMVs）。我们提出，真核生物内膜系统起源于线粒体祖先在真核生物起源时，在其古菌宿主的细胞质中释放的细菌 OMVs。这些 OMVs 被限制在宿主的细胞质中，自然地积累，要么彼此融合，要么与宿主的质膜融合。这种融合方式与宿主的古菌分泌途径相匹配，用于共翻译蛋白插入，同时向外运输由细菌脂质组成的线粒体衍生囊泡，从而形成原始的、分泌型的内质网，作为真核生物内膜系统的基石。
