Surface-catalyzed liquid-liquid phase separation and amyloid-like assembly in microscale compartments.

Area of Science:

• Biochemistry
• Cell Biology
• Materials Science

Background:

• Liquid-liquid phase separation (LLPS) drives the formation of membrane-less cellular structures called biomolecular condensates.
• Protein condensates can evolve into ordered amyloid aggregates, relevant to cellular function and disease.

Purpose of the Study:

• To investigate the formation of amyloid-like structures from Human Insulin under specific experimental conditions.
• To elucidate the role of interfaces and surface-to-volume ratios in amyloid formation driven by LLPS.

Main Methods:

• Utilizing sub-microliter aqueous compartments and room temperature conditions.
• Employing quantitative fluorescence microscopy for real-time observation of superstructure formation.
• Manipulating the surface-to-volume ratio of aqueous compartments.

Main Results:

• Human Insulin forms micrometric, round amyloid-like particles with a solid core and fluid corona at the aqueous-glass interface.
• Particle formation is driven by LLPS originating from heterogeneous nuclei distribution at the interface.
• Surface-to-volume ratio significantly affects aggregation rate, particle size, and molecular structure.

Conclusions:

• Surfaces play a catalytic role in amyloid structure formation.
• LLPS and interfacial phenomena are critical factors in controlling amyloid assembly.
• The study provides insights into factors governing amyloid formation and condensate evolution.