2021 Fiscal Year Annual Research Report
Unraveling the role of membrane contact sites in Entamoeba histolytica
| Project/Area Number |
20K16233
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| Research Institution | The University of Tokyo |
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Principal Investigator |
サントス ハルベルト・ヒメネス 東京大学, 大学院医学系研究科(医学部), 助教 (90793779)
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Keywords | Entamoeba histolytica / EHD1 / endosome / membrane contact site / mitosome |
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| Outline of Annual Research Achievements |
We previously discovered several Entamoeba-specific transmembrane mitosomal proteins (ETMPs) from in silico and cell biological analyses. One of them, ETMP1 (EHI_175060), was predicted to have one transmembrane domain and two coiled-coil regions, and was demonstrated to be mitosome membrane-integrated based on carbonate fractionation and immunoelectron microscopy (IEM) data. Immunoprecipitation analysis detected a candidate interacting partner, EH-domain containing protein (EHD1, EHI_105270). We expressed HA-tagged EHD1 in E. histolytica and subsequent immunofluorescence and IEM data indicated an unprecedented MCS between the mitosome and the endosome. Live imaging of GFP-EHD1 expressing strain demonstrated that EHD1 is involved in early endosome formation, and is observed in MCS between endosomes of various sizes. In vitro assay using recombinant His-EHD1 demonstrated ATPase activity. MCSs are involved in lipid transfer, ion homeostasis, and organelle dynamics. The serendipitous discovery of the ETMP1 interacting partner EHD1, led to the observation of the mitosome-endosome contact site in E. histolytica. It opened a new view of how the relic mitochondria of Entamoeba may likewise be involved in organelle crosstalk, a conserved feature of mitochondria and other organelles in general.
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