Amyloid propagation analyais by reconstitution system

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H00501
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 48:Biomedical structure and function and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: TANAKA Motomasa 国立研究開発法人理化学研究所, 脳神経科学研究センター, チームリーダー (40321781)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: アミロイド / 脱凝集 / 酵母プリオン / 伝播

Outline of Final Research Achievements

Disaggregation of amyloid fibrils is a fundamental biological process required for amyloid propagation. However, due to the lack of experimental systems, the molecular mechanism of how amyloid is disaggregated by cellular factors remains poorly understood. Here, we established a robust in vitro reconstituted system of yeast prion propagation and found that heat-shock protein 104 (Hsp104), Ssa1 and Sis1 chaperones are essential for efficient disaggregation of Sup35 amyloid. Real-time imaging of single-molecule fluorescence coupled with the reconstitution system revealed that amyloid disaggregation is achieved by ordered, timely binding of the chaperones to amyloid. Remarkably, we uncovered two distinct prion strain conformation-dependent modes of disaggregation, fragmentation and dissolution. We characterized distinct chaperone dynamics in each mode and found that transient, repeated binding of Hsp104 to the same site of amyloid results in fragmentation.

Free Research Field

構造神経科学

Academic Significance and Societal Importance of the Research Achievements

アミロイドの脱凝集は凝集体を失わせるため、本研究の成果はアミロイドが関わる多くの神経変性疾患の治療に結びつく知見を与える。一方で、全ての凝集体を完全にモノマーにまで脱凝集できればよいのだが、もしそうでなければ、中途半端なアミロイドの脱凝集は細胞内にシードを多く産み出すため、それは細胞にとっては逆効果になることも考えられる。したがって今後は、本研究の成果をもとに、アミロイドの脱凝集をより深く理解するこに加え、アミロイドの選択的な分解をも指向した研究を進めることで、神経変性疾患の予防や治療に役立つと考えられる。