# A Split Biotin Ligase Approach to Revealing Proteins Associated with Oligomeric Alpha-Synuclein During Aggregation

## TL;DR

This study identifies proteins that interact with alpha-synuclein during early aggregation stages, revealing potential mechanisms in Lewy body diseases.

## Contribution

A novel split biotin ligase approach was used to identify proteins specifically associated with multimeric alpha-synuclein.

## Key findings

- 581 proteins were identified as potential interactors of monomeric versus multimeric alpha-synuclein.
- Key findings include phosphorylation mechanisms, insulin processing connections, and interaction with ALS-associated FUS.
- Loss of specific interactions may contribute to pathology in sporadic Lewy body diseases.

## Abstract

Lewy pathology can form over decades in patients with Lewy body diseases, but the causal cellular mechanisms associated with this process remain unclear. This project aims to discover proteins that associate with monomeric and/or oligomeric alpha-synuclein during early stages of the aggregation process. To mimic the aggregation processes, cells expressing a synuclein-biotin ligase fusion protein were treated human recombinant pre-formed fibrils and subjected to BioSITe and mass spectrometry. Using a novel split biotin ligase fused to alpha-synuclein facilitated the identification of proteins specifically associated with multimeric alpha-synuclein. A total of 581 proteins were differentiated into potential interactors of monomeric versus multimeric alpha-synuclein in physiological versus aggregated conditions. The data reveal important phosphorylation mechanisms, connections to insulin processing, and a potential interaction with ALS-associated FUS. Interestingly, we identified that loss of specific interactions may contribute to pathology in patients with sporadic onset of Lewy body diseases. Future studies will validate both true interaction of highlighted proteins with alpha-synuclein, and the impact of such proteins on alpha-synuclein aggregation.