The Hsc70 disaggregation machinery removes monomer units directly from α-synuclein fibril ends

• Published in: Nature communications Vol. 12; no. 1; p. 5999
• Main Authors: Schneider, Matthias M., Gautam, Saurabh, Herling, Therese W., Andrzejewska, Ewa, Krainer, Georg, Miller, Alyssa M., Trinkaus, Victoria A., Peter, Quentin A. E., Ruggeri, Francesco Simone, Vendruscolo, Michele, Bracher, Andreas, Dobson, Christopher M., Hartl, F. Ulrich, Knowles, Tuomas P. J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.10.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 101/62; 147/3; 631/45/470/1981; 631/45/470/2284; 631/57/2265; 631/57/2272/1590; 639/638/440/56; 82/62; alpha-Synuclein - metabolism; Amyloid; Amyloid - metabolism; Chaperones; Chemical kinetics; Disaggregation; Drug development; Escherichia coli; Fibrils; HSC70 Heat-Shock Proteins - genetics; HSC70 Heat-Shock Proteins - metabolism; Hsc70 protein; HSP40 Heat-Shock Proteins; HSP70 Heat-Shock Proteins - metabolism; Hsp70 protein; Humanities and Social Sciences; Humans; Kinetics; Microfluidics; Molecular Chaperones - metabolism; Monomers; Movement disorders; multidisciplinary; Neurodegenerative diseases; Parkinson Disease - metabolism; Parkinson's disease; Protein folding; Proteins; Reaction kinetics; Science; Science (multidisciplinary); Synuclein
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25966-w

Molecular chaperones contribute to the maintenance of cellular protein homoeostasis through assisting de novo protein folding and preventing amyloid formation. Chaperones of the Hsp70 family can further disaggregate otherwise irreversible aggregate species such as α-synuclein fibrils, which accumulate in Parkinson’s disease. However, the mechanisms and kinetics of this key functionality are only partially understood. Here, we combine microfluidic measurements with chemical kinetics to study α-synuclein disaggregation. We show that Hsc70 together with its co-chaperones DnaJB1 and Apg2 can completely reverse α-synuclein aggregation back to its soluble monomeric state. This reaction proceeds through first-order kinetics where monomer units are removed directly from the fibril ends with little contribution from intermediate fibril fragmentation steps. These findings extend our mechanistic understanding of the role of chaperones in the suppression of amyloid proliferation and in aggregate clearance, and inform on possibilities and limitations of this strategy in the development of therapeutics against synucleinopathies. Molecular chaperones from the Hsp70 family can break up protein aggregates, including amyloids. Here, the authors utilize microfluidic diffusional sizing to assess the mechanism of α-synuclein (αS) disaggregation by the Hsc70–DnaJB1–Apg2 system, and show that single αS molecules are removed directly from the fibril ends.