Fluctuation methods to study protein aggregation in live cells: concanavalin A oligomers formation

Area of Science:

• Biophysics
• Cell Biology
• Neuroscience

Background:

• Prefibrillar protein oligomers are implicated as key pathogenic agents in neurodegenerative diseases.
• Directly probing protein oligomer formation within living cells is crucial for understanding disease mechanisms.

Purpose of the Study:

• To monitor the aggregation process of Concanavalin A (ConA) in live cells.
• To correlate protein aggregation with cellular changes and membrane properties.

Main Methods:

• Utilized number and brightness analysis, two-color cross number and brightness analysis, and Raster Image Correlation Spectroscopy (RICS).
• Quantified molecular number, aggregation state, and diffusion coefficients over time and location within cells.
• Employed Laurdan generalized polarization imaging to assess membrane water penetration.

Main Results:

• Observed Concanavalin A binding to the cell membrane and subsequent aggregate formation.
• Correlated protein aggregation with progressive cell morphology changes, including compaction and cell death.
• Detected increased membrane water penetration following protein aggregation.

Conclusions:

• Concanavalin A aggregation dynamics in live cells can be quantitatively monitored using advanced imaging techniques.
• The study provides a cellular model linking protein aggregation, membrane alterations, and cell death, relevant to neurodegenerative disease pathogenesis.