Role of epsin 1 in synaptic vesicle endocytosis
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Edited by Pietro V. De Camilli, Yale University School of Medicine, New Haven, CT, and approved March 6, 2008 (received for review October 29, 2007)
Abstract
Epsin has been suggested to act as an alternate adaptor in several endocytic pathways. Its role in synaptic vesicle recycling remains, however, unclear. Here, we examined the role of epsin in this process by using the lamprey reticulospinal synapse as a model system. We characterized a lamprey ortholog of epsin 1 and showed that it is accumulated at release sites at rest and also at clathrin-coated pits in the periactive zone during synaptic activity. Disruption of epsin interactions, by presynaptic microinjection of antibodies to either the epsin-N-terminal homology domain (ENTH) or the clathrin/AP2 binding region (CLAP), caused profound loss of vesicles in stimulated synapses. CLAP antibody-injected synapses displayed a massive accumulation of distorted coated structures, including coated vacuoles, whereas in synapses perturbed with ENTH antibodies, very few coated structures were found. In both cases coated pits on the plasma membrane showed a shift to early intermediates (shallow coated pits) and an increase in size. Moreover, in CLAP antibody-injected synapses flat clathrin-coated patches occurred on the plasma membrane. We conclude that epsin is involved in clathrin-mediated synaptic vesicle endocytosis. Our results support a model, based on in vitro studies, suggesting that epsin coordinates curvature generation with coat assembly and further indicating that epsin limits clathrin coat assembly to the size of newly formed vesicles. We propose that these functions of epsin 1 provide an additional mechanism for generation of uniformly sized synaptic vesicles.
Footnotes
- †To whom correspondence may be addressed. E-mail: lennart.brodin{at}ki.se
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Author contributions: J.J., O.S., and L.B. designed research; J.J., H.G., F.A., P.L., O.S., and L.B. performed research; J.J. analyzed data; and J.J., O.S., and L.B. wrote the paper.
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↵*Present address: Department of Genetics, Microbiology, and Toxicology, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
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Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. EU623434).
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This article contains supporting information online at www.pnas.org/cgi/content/full/0710267105/DCSupplemental.
- © 2008 by The National Academy of Sciences of the USA
