Proteomic screening for amyloid proteins.

Area of Science:

• Biochemistry
• Proteomics
• Molecular Biology

Background:

• Elucidating amyloid functions and roles in pathology is hindered by a lack of universal and reliable biochemical discovery methods.
• Existing methods primarily identify glutamine/asparagine-rich amyloid-forming proteins or those in large deposits.

Purpose of the Study:

• To present a novel proteomic approach for identifying a broad spectrum of amyloid-forming proteins.
• To enable discovery of amyloids independent of sequence features or expression levels.

Main Methods:

• Isolation of protein fractions enriched with amyloid aggregates using ultracentrifugation with detergents (sarkosyl or SDS).
• Separation of sedimented proteins by 2D difference gel electrophoresis or SDS-PAGE.
• Identification of proteins using mass spectrometry.

Main Results:

• Validated the approach by detecting known yeast prions and mammalian amyloidogenic proteins.
• Identified yeast proteins forming detergent-insoluble aggregates in the presence of human huntingtin with expanded polyglutamine.
• Most identified proteins contained glutamine/asparagine-rich regions, suggesting cross-seeding by huntingtin.

Conclusions:

• The developed proteomic approach is an efficient and universal tool for screening amyloid proteins.
• This method can be applied to any organism, advancing amyloid research.
• Facilitates broader discovery of amyloid-forming proteins beyond current limitations.