Novel secretion mechanisms from ER independent of signal peptide in protozoan parasites

• Project/Area Number: 19K07531
• 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: National Institute of Infectious Diseases
• Principal Investigator: Saito-Nakano Yumiko 国立感染症研究所, 寄生動物部, 主任研究官 (30321764)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 赤痢アメーバ / マラリア原虫 / Rab GTPase / メンブレントラフィック / Arf GTPase / Sec7 / Plasmodium / ミリストイル / GTPase / Entamoeba histolytica / traffic / 原虫 / 小胞体 / シグナルペプチド

Outline of Research at the Start

細胞外へのタンパク質輸送は、病原体の感染と宿主応答において多くの重要な役割を担う。これまでの通説では、細胞外に分泌されるタンパク質にはN末端にシグナルペプチドが存在し、小胞体に組み込まれた後、小胞を介して細胞外に分泌される。しかし、シグナルペプチドが無くとも細胞外に分泌されるタンパク質は原虫や宿主細胞で複数報告されており、そのメカニズムは不明である。本申請では赤痢アメーバを対象とし、申請者が発見した小胞体に局在するRab8A GTPaseによって制御される細胞表面タンパク質の輸送を解明する。

Outline of Final Research Achievements

The N-terminus signal peptide of secreted proteins is required for the protein to be transported out of the endoplasmic reticulum. However, several secreted proteins without a signal peptide have been reported in protozoa and host cells. In this study, I showed that EhTolA is transported to the cell surface by the endoplasmic reticulum-localized Rab8A GTPase in Entamoeba histolytica. N-terminal myristylation modification of EhTolA was necessary for transport to the amebic cell surface. In addition, myristoylated PfRab5b GTPase, which is localized to the ER, is involved in the transport of myristoylated substrate, AK2, to the parasitophorous vacuolar membrane in Plasmodium falciparum. The regulatory factors involved in the regulation of PfRab5b were also analyzed.

Academic Significance and Societal Importance of the Research Achievements

寄生性原虫は宿主表面の抗原を認識・接着した後に細胞侵入を開始するため、原虫の細胞表面への表面抗原の輸送機構の解明は重要である。本申請課題で解析を行った赤痢アメーバとマラリア原虫は共に国内外で感染者が多く、感染防御の機構解明が必要である。本研究結果により赤痢アメーバとマラリア原虫は、共に特殊な細胞内輸送系を獲得していることが明らかになった。

Research Products

• [Journal Article] Prevalence and metronidazole resistance of Trichomonas vaginalis among Japanese women in 2021 (2023)
  • Author(s): Saito-Nakano Y, Umeki Y, Shimokawa C, Kobayashi K, Hashimoto K, Takada T, Makii C, Hasebe R, Yoshida Y, Nakajima R, Kobayashi S, Hisaeda H.
  • Journal Title: IJID Reg Volume: 7 Pages: 130-135
  • DOI: 10.1016/j.ijregi.2023.02.007
  • Peer Reviewed / Open Access
• [Journal Article] Attenuation of In Vitro and In Vivo Virulence Is Associated with Repression of Gene Expression of AIG1 Gene in Entamoeba histolytica (2023)
  • Author(s): Lozano-Mendoza J, Ramirez-Montiel F, Rangel-Serrano A, Paramo-Perez I, Mendoza-Macias C, Saavedra-Salazar F, Franco B, Vargas-Maya N, Jeelani G, Saito-Nakano Y, Anaya-Velazquez F, Nozaki T, Padilla-Vaca F
  • Journal Title: Pathogens Volume: 12 Issue: 3 Pages: 489-489
  • DOI: 10.3390/pathogens12030489
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Gene expression of axenically-isolated clinical Entamoeba histolytica strains and its impact on disease severity of amebiasis (2022)
  • Author(s): Yanagawa Yasuaki、Izumiyama Shinji、Saito-Nakano Yumiko、Nakada-Tsukui Kumiko、Kobayashi Seiki、Yoshida Naoko、Kikuchi Yoshimi、Gatanaga Hiroyuki、Oka Shinichi、Nozaki Tomoyoshi、Watanabe Koji
  • Journal Title: PLOS Pathogens Volume: 18 Issue: 9 Pages: e1010880-e1010880
  • DOI: 10.1371/journal.ppat.1010880
  • Peer Reviewed / Open Access
• [Journal Article] <i>In Vitro</i> and <i>In Vivo</i> Antiamebic Activity of Iron-Targeting Polypyridine Compounds against Enteric Protozoan Parasite <i>Entamoeba histolytica</i> (2022)
  • Author(s): Wada Akira、Umeki Yuko、Annoura Takeshi、Saito-Nakano Yumiko
  • Journal Title: ACS Infectious Diseases Volume: 8 Issue: 3 Pages: 457-462
  • DOI: 10.1021/acsinfecdis.1c00418
  • Peer Reviewed / Open Access
• [Journal Article] ArfX2 GTPase Regulates Trafficking From the Trans-Golgi to Lysosomes and Is Necessary for Liver Abscess Formation in the Protozoan Parasite Entamoeba histolytica (2021)
  • Author(s): Saito-Nakano Yumiko、Makiuchi Takashi、Tochikura Mami、Gilchrist Carol A.、Petri William A.、Nozaki Tomoyoshi
  • Journal Title: Frontiers in Cellular and Infection Microbiology Volume: 11 Pages: 794152-794152
  • DOI: 10.3389/fcimb.2021.794152
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rab5b-Associated Arf1 GTPase Regulates Export of N-Myristoylated Adenylate Kinase 2 From the Endoplasmic Reticulum in Plasmodium falciparum (2021)
  • Author(s): Taku Izumi、Hirai Tomohiro、Makiuchi Takashi、Shinzawa Naoaki、Iwanaga Shiroh、Annoura Takeshi、Nagamune Kisaburo、Nozaki Tomoyoshi、Saito-Nakano Yumiko
  • Journal Title: Frontiers in Cellular and Infection Microbiology Volume: 10 Pages: 610200-610200
  • DOI: 10.3389/fcimb.2020.610200
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Rab7D small GTPase is involved in phago‐, trogocytosis and cytoskeletal reorganization in the enteric protozoan Entamoeba histolytica (2020)
  • Author(s): Saito‐Nakano Yumiko、Wahyuni Ratna、Nakada‐Tsukui Kumiko、Tomii Kentaro、Nozaki Tomoyoshi
  • Journal Title: Cellular Microbiology Volume: 23 Issue: 1
  • DOI: 10.1111/cmi.13267
  • Peer Reviewed / Open Access
• [Presentation] 赤痢アメーバにおける膜輸送の多様化とアメーバ性肝膿瘍形成に必要なトランスゴルジ輸送を制御するArfX2 GTPaseの役割 (2023)
  • Author(s): 中野 由美子, 牧内 貴志, 栃倉 麻美, 津久井 久美子, Carol A. Gilchrist, William A. Petri Jr, 野崎 智義
  • Organizer: 第92回日本寄生虫学会大会
• [Presentation] 婦人科におけるトリコモナスの無症侯感染とメトロニダゾール感受性 (2022)
  • Author(s): 中野 由美子, 梅木 優子, 下川 周子, 小林 浩一, 橋本耕一, 髙田恭臣, 牧井千波, 長谷部里衣, 吉田友里, 中島理子, 小林 正規, 久枝 一
  • Organizer: 第91回日本寄生虫学会大会
• [Presentation] Entamoeba moshkovskii; new upcoming Entamoeba infection in India (2022)
  • Author(s): Sanjib Kumar Sardar, Yumiko Saito-Nakano, Shanta Dutta, Tomoyoshi Nozaki, Sandipan Ganguly
  • Organizer: ICOPA
  • Int'l Joint Research
• [Presentation] 熱帯熱マラリア原虫Rab5bの結合タンパク質はN-ミリストイル化adenylate kinase 2を小胞体から選別輸送する (2021)
  • Author(s): 多久 和泉, 平井 智浩, 牧内 貴志, 新澤 直明, 岩永 史朗, 案浦 健, 永宗 喜三郎, 野崎 智義, 中野 由美子
  • Organizer: 第90回日本寄生虫学会大会
• [Presentation] Rab5b associated proteins regulate the transport of N-myristoylated AK2 from the endoplasmic reticulum in Plasmodium falciparum (2021)
  • Author(s): Izumi Taku, Tomohiro Hirai, Takashi Makiuchi, Naoaki Shinzawa, Shiroh Iwanaga, Takeshi Annoura, Kisaburo Nagamune, Tomoyoshi Nozaki, Yumiko Saito-Nakano
  • Organizer: Woods Hole Molecular Parasitology Meeting MPM XXXII
  • Int'l Joint Research
• [Presentation] 熱帯熱マラリア原虫N-アシル化Rab5bとArf1は小胞体近傍から寄生胞膜への輸送に関与する (2019)
  • Author(s): 多久 和泉, 平井 智浩, 新澤 直明, 岩永 史朗, 牧内 貴志, 永宗 喜三郎, 野崎 智義, 中野 由美子
  • Organizer: 第71回日本細胞生物学会大会・第19回日本蛋白質科学学会 合同年次大会
• [Presentation] 熱帯熱マラリア原虫N-アシル化Rab5bとArf1, Ran1bの小胞体近傍における局在解析 (2019)
  • Author(s): 多久 和泉, 平井 智浩, 新澤 直明, 岩永 史朗, 牧内 貴志, 永宗 喜三郎, 野崎 智義, 中野 由美子
  • Organizer: 第79回日本寄生虫学会東日本支部大会