The significance of a DRP hetero-oligomer in the fission of Entamoeba mitosomes.

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K07096
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49040:Parasitology-related
• Research Institution: Tokai University
• Principal Investigator: MAKIUCHI Takashi 東海大学, 医学部, 講師 (80587709)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 寄生虫 / 赤痢アメーバ / ミトコンドリア / マイトソーム / ダイナミン

Outline of Final Research Achievements

The unexplained heterocomplex comprised of two dynamin-related proteins in Entamoeba histolytica (EhDrpA and EhDrpB) was investigated to elucidate the rationale of its establishment. This heterocomplex participates in the fission of mitosomes that have undergone reductive evolution of mitochondria. Electron microscopy observations suggested that the EhDrpB homocomplex is unlikely to be involved in mitosomal fission as its size is unsuitable for the fission constriction site. Analyses using the stage conversion model Entamoeba invadens suggested the possibility that quantitative changes in EhDrpA and EhDrpB homologs may regulate mitosomal fission during encystation. Moreover, the differences in the expression profiles between these homologs indicate that the resulting homocomplexes may have different functions during encystation. Therefore, it is thought that the heterocomplex has been established to create functional differentiation through quaternary structure diversification.

Free Research Field

寄生虫学

Academic Significance and Societal Importance of the Research Achievements

赤痢アメーバは、２種類のダイナミン関連タンパク質からホモ複合体２種類とヘテロ複合体、計３種類の機能が異なる複合体を形成している可能性が高い。寄生性真核生物からは、ゲノム・代謝経路・オルガネラ等で縮退進化が報告されている。赤痢アメーバにおいても同様な進化が報告されているが、オルガネラのダイナミクス制御分子に関して、本研究から四次構造の多様化によって遺伝子数以上の機能分化を生み出すという縮退進化の一助と考えられる特殊な進化が起きた可能性が示された。