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A role for the ubiquitin-proteasome system in activity-dependent presynaptic silencing.

Authors
  • Jiang, Xiaoping1
  • Litkowski, Patricia E
  • Taylor, Amanda A
  • Lin, Ying
  • Snider, B Joy
  • Moulder, Krista L
  • 1 Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Type
Published Article
Journal
Journal of Neuroscience
Publisher
Society for Neuroscience
Publication Date
Feb 03, 2010
Volume
30
Issue
5
Pages
1798–1809
Identifiers
DOI: 10.1523/JNEUROSCI.4965-09.2010
PMID: 20130189
Source
Medline
License
Unknown

Abstract

Chronic changes in electrical excitability profoundly affect synaptic transmission throughout the lifetime of a neuron. We have previously explored persistent presynaptic silencing, a form of synaptic depression at glutamate synapses produced by ongoing neuronal activity and by strong depolarization. Here we investigate the involvement of the ubiquitin-proteasome system (UPS) in the modulation of presynaptic function. We found that proteasome inhibition prevented the induction of persistent presynaptic silencing. Specifically, application of the proteasome inhibitor MG-132 (carbobenzoxy-L-leucyl-L-leucyl-L-leucinal) prevented decreases in the size of the readily releasable pool of vesicles and in the percentage of active synapses. Presynaptic silencing was accompanied by decreases in levels of the priming proteins Munc13-1 and Rim1. Importantly, overexpression of Rim1alpha prevented the induction of persistent presynaptic silencing. Furthermore, strong depolarization itself increased proteasome enzymatic activity measured in cell lysates. These results suggest that modulation of the UPS by electrical activity contributes to persistent presynaptic silencing by promoting the degradation of key presynaptic proteins.

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