Formation of toxic oligomeric alpha-synuclein species in living cells

PLoS One. 2008 Apr 2;3(4):e1867. doi: 10.1371/journal.pone.0001867.


Background: Misfolding, oligomerization, and fibrillization of alpha-synuclein are thought to be central events in the onset and progression of Parkinson's disease (PD) and related disorders. Although fibrillar alpha-synuclein is a major component of Lewy bodies (LBs), recent data implicate prefibrillar, oligomeric intermediates as the toxic species. However, to date, oligomeric species have not been identified in living cells.

Methodology/principal findings: Here we used bimolecular fluorescence complementation (BiFC) to directly visualize alpha-synuclein oligomerization in living cells, allowing us to study the initial events leading to alpha-synuclein oligomerization, the precursor to aggregate formation. This novel assay provides us with a tool with which to investigate how manipulations affecting alpha-synuclein aggregation affect the process over time. Stabilization of alpha-synuclein oligomers via BiFC results in increased cytotoxicity, which can be rescued by Hsp70 in a process that reduces the formation of alpha-synuclein oligomers. Introduction of PD-associated mutations in alpha-synuclein did not affect oligomer formation but the biochemical properties of the mutant alpha-synuclein oligomers differ from those of wild type alpha-synuclein.

Conclusions/significance: This novel application of the BiFC assay to the study of the molecular basis of neurodegenerative disorders enabled the direct visualization of alpha-synuclein oligomeric species in living cells and its modulation by Hsp70, constituting a novel important tool in the search for therapeutics for synucleinopathies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cell Line, Tumor
  • Cricetinae
  • Cricetulus
  • HSP70 Heat-Shock Proteins / chemistry
  • Humans
  • Lewy Bodies / metabolism
  • Microscopy, Fluorescence / methods
  • Mutation*
  • Parkinson Disease / metabolism
  • Protein Folding
  • Protein Structure, Tertiary
  • alpha-Synuclein / chemistry*
  • alpha-Synuclein / genetics*
  • alpha-Synuclein / metabolism


  • HSP70 Heat-Shock Proteins
  • alpha-Synuclein