Amyloid conformation-dependent disaggregation in a reconstituted yeast prion system

Area of Science:

• Biochemistry
• Molecular Biology
• Neuroscience

Background:

• Amyloid fibril disaggregation is vital for prion and amyloid propagation.
• The molecular mechanisms of cellular amyloid disaggregation are poorly understood due to limited experimental systems.

Purpose of the Study:

• To elucidate the molecular mechanisms of amyloid disaggregation by cellular factors.
• To establish a reconstituted in vitro system for studying yeast prion propagation and amyloid disaggregation.

Main Methods:

• Development of a robust in vitro reconstituted system for yeast prion propagation.
• Real-time single-molecule fluorescence imaging to observe chaperone-amyloid interactions.
• Characterization of chaperone dynamics during amyloid disaggregation.

Main Results:

• Heat-shock protein 104 (Hsp104), Ssa1, and Sis1 chaperones are essential for Sup35 amyloid disaggregation.
• Amyloid disaggregation occurs through ordered, timely chaperone binding.
• Two distinct prion strain conformation-dependent disaggregation modes were identified: fragmentation and dissolution.
• Transient, repeated Hsp104 binding promotes fragmentation.

Conclusions:

• The study provides a mechanistic understanding of amyloid disaggregation by chaperones.
• Findings offer insights into prion strain diversity and propagation.
• The results lay a foundation for therapeutic strategies targeting amyloid-associated neurodegenerative diseases.