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Paulussen I, Beckert H, Musial TF, Gschossmann LJ, Wolf J, Schmitt M, Clasadonte J, Mairet-Coello G, Wolff C, Schoch S, Dietrich D. SV2B defines a subpopulation of synaptic vesicles. J Mol Cell Biol 2023:mjad054. [PMID: 37682518 DOI: 10.1093/jmcb/mjad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023] Open
Abstract
Synaptic vesicles can undergo several modes of exocytosis, endocytosis, and trafficking within individual synapses, and their fates may be linked to differences in the vesicular protein composition. Here, we mapped the intrasynaptic distribution of the synaptic vesicle proteins SV2B and SV2A in glutamatergic synapses of the hippocampus using three-dimensional electron microscopy. SV2B is almost completely absent from both docked vesicles and a distinct cluster of vesicles found near the active zone. In contrast, SV2A was found in all domains of the synapse and was slightly enriched near the active zone. SV2B and SV2A were found on the membrane in the peri-active zone, suggesting recycling from both clusters of vesicles. SV2B knockout mice displayed an increased seizure induction threshold only in a model employing high-frequency stimulation. Our data show that glutamatergic synapses generate molecularly distinct populations of synaptic vesicles and are able to maintain them at steep spatial gradients. The almost complete absence of SV2B from vesicles at the active zone of wildtype mice may explain why SV2A has been found to be more important for vesicle release.
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Affiliation(s)
- Isabelle Paulussen
- Department of Neurosurgery, University Hospital Bonn, Bonn 53127, Germany
- Department of Neuropathology, University Hospital Bonn, Bonn 53127, Germany
| | - Hannes Beckert
- Microscopy Core Facility, Medical Faculty, University of Bonn, Bonn 53127, Germany
| | - Timothy F Musial
- Microscopy Core Facility, Medical Faculty, University of Bonn, Bonn 53127, Germany
| | - Lena J Gschossmann
- Department of Neurosurgery, University Hospital Bonn, Bonn 53127, Germany
- Department of Neuropathology, University Hospital Bonn, Bonn 53127, Germany
| | - Julia Wolf
- Department of Neurosurgery, University Hospital Bonn, Bonn 53127, Germany
- Department of Neuropathology, University Hospital Bonn, Bonn 53127, Germany
| | | | | | | | | | - Susanne Schoch
- Department of Neuropathology, University Hospital Bonn, Bonn 53127, Germany
| | - Dirk Dietrich
- Department of Neurosurgery, University Hospital Bonn, Bonn 53127, Germany
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