title: Single-channel electrophysiology reveals a distinct and uniform pore complex formed by α-synuclein oligomers in lipid membranes.
abstract: Synucleinopathies such as Parkinson's disease, multiple system atrophy and dementia with Lewy bodies are characterized by deposition of aggregated α-synuclein. Recent findings indicate that pathological oligomers rather than fibrillar aggregates may represent the main toxic protein species. It has been shown that α-synuclein oligomers can increase the conductance of lipid bilayers and, in cell-culture, lead to calcium dyshomeostasis and cell death. In this study, employing a setup for single-channel electrophysiology, we found that addition of iron-induced α-synuclein oligomers resulted in quantized and stepwise increases in bilayer conductance indicating insertion of distinct transmembrane pores. These pores switched between open and closed states depending on clamped voltage revealing a single-pore conductance comparable to that of bacterial porins. Pore conductance was dependent on transmembrane potential and the available cation. The pores stably inserted into the bilayer and could not be removed by buffer exchange. Pore formation could be inhibited by co-incubation with the aggregation inhibitor baicalein. Our findings indicate that iron-induced α-synuclein oligomers can form a uniform and distinct pore species with characteristic electrophysiological properties. Pore formation could be a critical event in the pathogenesis of synucleinopathies and provide a novel structural target for disease-modifying therapy.
authors.affiliation: Neurologische Klinik, Klinikum der Universität München, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Schmidt
authors.forename: Johannes
authors.initials: J
authors.lastname: Levin
authors.forename: Frits
authors.initials: F
authors.lastname: Kamp
authors.forename: Hans
authors.initials: H
authors.lastname: Kretzschmar
authors.forename: Armin
authors.initials: A
authors.lastname: Giese
authors.forename: Kai
authors.initials: K
authors.lastname: Bötzel
mesh_terms: D002412:Cations; D004553:Electric Conductivity; D055724:Electrophysiological Phenomena; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism*; D008954:Models, Biological; D016062:Porosity; D020836:Protein Structure, Quaternary; D013997:Time Factors; D051844:alpha-Synuclein / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D002412:Cations; D008051:Lipid Bilayers; D051844:alpha-Synuclein