Determination of α-Synuclein Protein Interactions by μMap Photo-proximity Labeling

Area of Science:

• Neuroscience
• Biochemistry
• Molecular Biology

Background:

• Fibrillar aggregates of alpha-synuclein (αS) are key indicators in Parkinson's disease and related synucleinopathies.
• Understanding the molecular interactions of αS is crucial for elucidating disease mechanisms, including both loss of healthy function and gain of toxic function.

Purpose of the Study:

• To determine the interactomes of αS monomers and fibrils in mouse brain lysate using photo-proximity labeling.
• To identify differences in αS interactions between its monomeric and fibrillar states to better understand synucleinopathies.

Main Methods:

• Micromap (μMap) photo-proximity labeling was employed to map αS interactomes.
• Several αS variants were synthesized with a small (1 kDa) iridium catalyst for minimally-perturbing labeling and a narrow labeling radius.
• Interactions were analyzed by comparing monomer and fibril interactomes with each other and with existing proximity labeling datasets.

Main Results:

• The study successfully mapped the interactomes of αS monomers and fibrils in mouse brain lysate.
• The minimally-perturbing nature and narrow labeling radius of the μMap technique allowed for the identification of specific interactome differences between αS states.
• Validation was performed by comparing results with previous datasets and through further investigations like Western blotting and super-resolution microscopy.

Conclusions:

• Micromap (μMap) photo-proximity labeling is an effective tool for studying protein interactions in complex biological systems like the brain.
• The identified interactome differences provide insights into the distinct roles of αS monomers and fibrils in the pathogenesis of synucleinopathies.
• Further investigations using μMap in primary neurons are warranted to validate findings in a more physiologically relevant context.