Impaired recycling of synaptic vesicles after acute perturbation of the presynaptic actin cytoskeleton
- Oleg Shupliakov*,†,
- Ona Bloom‡,§,
- Jenny S. Gustafsson*,
- Ole Kjaerulff*,¶,
- Peter Löw*,
- Nikolay Tomilin*,
- Vincent A. Pieribone‡,∥,
- Paul Greengard‡, and
- Lennart Brodin*
- *Nobel Institute for Neurophysiology, Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden; and‡ Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021
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Edited by Pietro V. De Camilli, Yale University School of Medicine, New Haven, CT, and approved August 28, 2002 (received for review June 27, 2002)
Abstract
Actin is an abundant component of nerve terminals that has been implicated at multiple steps of the synaptic vesicle cycle, including reversible anchoring, exocytosis, and recycling of synaptic vesicles. In the present study we used the lamprey reticulospinal synapse to examine the role of actin at the site of synaptic vesicle recycling, the endocytic zone. Compounds interfering with actin function, including phalloidin, the catalytic subunit of Clostridium botulinum C2 toxin, and N-ethylmaleimide-treated myosin S1 fragments were microinjected into the axon. In unstimulated, phalloidin-injected axons actin filaments formed a thin cytomatrix adjacent to the plasma membrane around the synaptic vesicle cluster. The filaments proliferated after stimulation and extended toward the vesicle cluster. Synaptic vesicles were tethered along the filaments. Injection of N-ethylmaleimide-treated myosin S1 fragments caused accumulation of aggregates of synaptic vesicles between the endocytic zone and the vesicle cluster, suggesting that vesicle transport was inhibited. Phalloidin, as well as C2 toxin, also caused changes in the structure of clathrin-coated pits in stimulated synapses. Our data provide evidence for a critical role of actin in recycling of synaptic vesicles, which seems to involve functions both in endocytosis and in the transport of recycled vesicles to the synaptic vesicle cluster.
Footnotes
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↵ † To whom correspondence should be addressed. E-mail: oleg.shupliakov{at}neuro.ki.se.
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↵ § Present address: Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520.
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↵ ¶ Present address: Institute of Medical Physiology, Copenhagen University, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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↵ ∥ Present address: John B. Pierce Laboratory, Yale University School of Medicine, New Haven, CT 06519.
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This paper was submitted directly (Track II) to the PNAS office.
- Abbreviations:
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NEM, N-ethylmaleimide
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NEM-S1, NEM-treated myosin subfragment 1
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- Copyright © 2002, The National Academy of Sciences
