Membrane-Bound Alpha Synuclein Clusters Induce Impaired Lipid Diffusion and Increased Lipid Packing

Area of Science:

• Biochemistry
• Biophysics
• Neuroscience

Background:

• Membrane-bound alpha-synuclein (αS) aggregation into oligomers/fibrils is linked to membrane damage.
• Previous studies suggest αS aggregation causes membrane dysfunction in vitro and in vivo.

Purpose of the Study:

• Investigate how αS interactions preceding aggregate formation influence physical membrane properties.
• Determine the impact of αS clustering on lipid bilayers.

Main Methods:

• Utilized three truncated αS variants with varying aggregation propensities.
• Employed fluorescence recovery after photobleaching (FRAP) and fluorescence anisotropy.
• Studied αS interactions on supported lipid bilayers (SLBs).

Main Results:

• αS cluster formation on SLBs immediately follows monomer addition.
• Clusters impair lateral lipid diffusion and increase lipid packing beneath them.
• Changes in lipid diffusion and order correlate with αS cluster size.

Conclusions:

• αS and membrane interactions drive the formation of ordered lipid domains.
• This αS-induced domain formation may contribute to alternative disease mechanisms.
• Understanding these early interactions is crucial for neurodegenerative disease research.