Analysis of the molecular pathogenesis of the selective autophagy substrate p62/SQSTM1 droplet

• Project/Area Number: 20K06549
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43030:Functional biochemistry-related
• Research Institution: Juntendo University
• Principal Investigator: Kageyama Shun 順天堂大学, 医学部, 助教 (30624225)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2021: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: オートファジー / p62-KEAP1-NRF2 / 酸化ストレス / リン酸化 / 液－液相分離 / 液滴 / p62/SQSTM1 / ULK1 / 酸化ストレス応答 / LC3/GABARAP / Keap1-Nrf2経路 / p62 / 相分離

Outline of Research at the Start

液滴は環境変化に応じて分子が濃縮し、効率的な生化学反応や不要分子を隔離する場として液-液相分離により形成される構造体である。神経変性疾患などの病変部位で確認される封入体は異常な液滴が蓄積、不溶化した凝集体であると考えられ、液滴形成・分解制御機構の解明は急務となっている。p62は相分離を引き起こす最も代表的なオートファジー選択的分解基質であり、多数の疾患関連アミノ酸変異が報告されているが、その病態発症機序は不明である。そこで本課題では、p62液滴分解の超微細構造、液滴の質的変化をもたらす翻訳後修飾によるp62の細胞機能の変化、および病態関連点変異によるp62液滴の細胞内動態の変化を明らかにする。

Outline of Final Research Achievements

The mechanism of selective autophagic degradation of p62 protein, which forms droplets by liquid-liquid phase separation, and the molecular pathogenesis of disease-related point mutations were unknown. Here, we found that p62 droplets serve as a scaffold for autophagosome formation and are selectively degraded via interaction with LC3/GABARAP proteins localized on the autophagosome membrane. We also found that the properties of p62 droplets are regulated by post-translational modifications and that disease-associated point mutations result in qualitative changes in p62 droplets.

Academic Significance and Societal Importance of the Research Achievements

神経変性疾患などで確認される封入体は生化学的機能を消失した液滴の凝集化体であると考えられるようになっており、液滴制御機構の解明は急務である。本研究は基礎研究領域のみならず臨床や創薬への応用まで大きく波及効果をもたらし、革新的・創造的な学術研究の発展に寄与すると期待される。

Research Products

• [Journal Article] Cathelicidin LL-37 activates human keratinocyte autophagy through the P2X7, mechanistic target of rapamycin, and MAPK pathways (2023)
  • Author(s): Ikutama R、Peng G、Tsukamoto S、Umehara Y、Trujillo-Paez JV、Yue H、Nguyen HLT、Takahashi M、Kageyama S、Komatsu M、Okumura K、Ogawa H、Ikeda Sh、Niyonsaba F
  • Journal Title: Journal of Investigative Dermatology Volume: 143 Issue: 5 Pages: 751-761.e7
  • DOI: 10.1016/j.jid.2022.10.020
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Human β-defensin-3 attenuates atopic dermatitis-like inflammation through autophagy activation and the aryl hydrocarbon receptor signaling pathway (2022)
  • Author(s): Peng G、Tsukamoto S、Ikutama R、Nguyen HLT、Umehara Y、Trujillo-Paez JV、Yue H、Takahashi M、Ogawa T、Kishi R、Tominaga M、Takamori K、Kitaura J、Kageyama S、Komatsu M、Okumura K、Ogawa H、Ikeda S、Niyonsaba F
  • Journal Title: Journal of Clinical Investigation Volume: 132 Issue: 17
  • DOI: 10.1172/jci156501
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Phase-separated protein droplets of amyotrophic lateral sclerosis-associated p62/SQSTM1 mutants show reduced inner fluidity (2021)
  • Author(s): Faruk MO, Ichimura Y, Kageyama S, Komatsu-Hirota S, El-Gowily AH, Sou YS, Koike M, Noda NN, Komatsu M.
  • Journal Title: J Biol Chem Volume: 297 Issue: 6 Pages: 101405-101405
  • DOI: 10.1016/j.jbc.2021.101405
  • Peer Reviewed / Open Access
• [Journal Article] p62/SQSTM1-droplet serves as a platform for autophagosome formation and anti-oxidative stress response (2021)
  • Author(s): Kageyama S, Gudmundsson SR, Sou YS, Ichimura Y, Tamura N, Kazuno S, Ueno T, Miura Y, Noshiro D, Abe M, Mizushima T, Miura N, Okuda S, Motohashi H, Lee JA, Sakimura K, Ohe T, Noda NN, Waguri S, Eskelinen EL, Komatsu M.
  • Journal Title: Nature Communications Volume: 12 Issue: 1 Pages: 16-16
  • DOI: 10.1038/s41467-020-20185-1
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] p62/SQSTM1 droplets initiate autophagosome biogenesis and oxidative stress control (2021)
  • Author(s): Eskelinen Eeva-Liisa、Kageyama Shun、Komatsu Masaaki
  • Journal Title: Molecular & Cellular Oncology Volume: 8 Issue: 2 Pages: 1890990-1890990
  • DOI: 10.1080/23723556.2021.1890990
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Autophagic receptor p62 protects against glycation‐derived toxicity and enhances viability (2020)
  • Author(s): Gemma Aragones, Kalavathi Dasuri, Opeoluwa Olukorede, Sarah G Francisco, Carol Renneburg, et al.
  • Journal Title: Aging Cell Volume: 19 Issue: 11
  • DOI: 10.1111/acel.13257
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] p62顆粒はオートファゴソーム形成とストレス応答の足場として働く機能的液滴である (2021)
  • Author(s): 蔭山 俊、Sigurdur Gudmundsson、曽 友深、一村 義信、田村 直輝、數野 彩子、上野 隆、三浦 芳樹、能代 大輔、阿部 学、水島 恒裕、三浦 信明、奥田 修二郎、本橋 ほづみ、Jin-A Lee、﨑村 建司、大江 知之、野田 展生、和栗 聡、Eeva-Liisa Eskelinen、小松 雅明
  • Organizer: 第73回 日本細胞生物学会大会
  • Invited
• [Presentation] 選択的オートファジーの動態解析と生理的意義の解明 (2020)
  • Author(s): 蔭山 俊、Sigurdur Gudmundsson、曽 友深、一村義信、田村直輝、數野彩子、上野 隆、三浦芳樹、能代大輔、阿部 学、水島恒裕、三浦信明、奥田修二郎、本橋ほづみ、 Jin-A Lee、﨑村建司、大江知之、野田展生、和栗 聡、Eeva-Liisa Eskelinen、小松雅明
  • Organizer: 第72回日本細胞生物学会大会
• [Presentation] p62/SQSTM1-droplet serves as a platform for autophagosome formation and anti-oxidative stress response (2020)
  • Author(s): Shun Kageyama, Sigurdur Runar Gudmundsson, Yu-Shin Sou, Yoshinobu Ichimura, Naoki Tamura, Saiko Kazuno, et al.
  • Organizer: VIRTUAL KEYSTONE SYMPOSIA Autophagy: Mechanisms and Disease
  • Int'l Joint Research