Hsc70 ameliorates the vesicle recycling defects caused by excess α-synuclein at synapses

Susan M.L. Banks, Audrey T. Medeiros, Molly McQuillan, David J. Busch, Ana Sofia Ibarraran-Viniegra, Rui Sousa, Eileen M. Lafer, Jennifer R. Morgan

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

α-Synuclein overexpression and aggregation are linked to Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and several other neurodegenerative disorders. In addition to effects in the cell body, α-synuclein accumulation occurs at presynapses where the protein is normally localized. While it is generally agreed that excess α-synuclein impairs synaptic vesicle trafficking, the underlying mechanisms are unknown. We show here that acute introduction of excess human α-synuclein at a classic vertebrate synapse, the lamprey reticulospinal (RS) synapse, selectively impaired the uncoating of clathrin-coated vesicles (CCVs) during synaptic vesicle recycling, leading to an increase in endocytic intermediates and a severe depletion of synaptic vesicles. Furthermore, human α-synuclein and lamprey +-synuclein both interact in vitro with Hsc70, the chaperone protein that uncoats CCVs at synapses. After introducing excess α-synuclein, Hsc70 availability was reduced at stimulated synapses, suggesting Hsc70 sequestration as a possible mechanism underlying the synaptic vesicle trafficking defects. In support of this hypothesis, increasing the levels of exogenous Hsc70 along with α-synuclein ameliorated the CCV uncoating and vesicle recycling defects. These experiments identify a reduction in Hsc70 availability at synapses, and consequently its function, as the mechanism by which α-synuclein induces synaptic vesicle recycling defects. To our knowledge, this is the first report of a viable chaperone-based strategy for reversing the synaptic vesicle trafficking defects associated with excess α-synuclein, which may be of value for improving synaptic function in PD and other synuclein-linked diseases.

Original languageEnglish (US)
Article numberENEURO.0448-19.2020
JournaleNeuro
Volume7
Issue number1
DOIs
StatePublished - 2020

Keywords

  • Auxilin
  • Chaperone
  • Clathrin
  • Clathrin-coated vesicles
  • Endocytosis
  • Lamprey

ASJC Scopus subject areas

  • Neuroscience(all)

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