| 研究実績の概要 |
We have analyzed the structures of Asgard archaea small GTPases, roadblock proteins and TRAPP proteins. The GTPase structure is similar to Rab GTPases, which in eukaryotes control the trafficking of vesicles between internal membranes. Asgard archaea do not possess internal membranes. However, the Asgard Rabs do not possess the C-terminal modification sites, which are needed to locate to discrete eukaryotic membranes. Thus, Rab proteins evolved their membrane specificity after proto-eukaryotes separated from Asgard archaea. The roadblock and TRAPP structures are also very similar between eukaryotes and Asgard archaea. However, Asgard form homodimers, whereas eukaryotes form heterodimers, indicating gene duplication and diversification were an important processes for eukaryotic evolution.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
Over the past year we have made several unexpected discoveries through expressing Asgard archaea proteins in mammalian cells. Several Asgard protein classes localize to the same regions of the eukaryotic cell as their eukaryotic counterparts. In particular, some proteins localize to eukaryotic internal membranes, which do not exist in Asgard archaea. These data have given us a new insight that the properties of existing pre-eukaryotic machines shaped the process of eukaryogenesis, since their fundamental properties remain intact during 2 billion years of evolution. This insight has advanced our understanding beyond what we proposed at the beginning of the project. Based on this understanding, we expect to make outstanding progress in the last year of our project.
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