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Scheuber A, Rudge R, Danglot L, Raposo G, Binz T, Poncer JC, Galli T. Loss of AP-3 function affects spontaneous and evoked release at hippocampal mossy fiber synapses. Proc Natl Acad Sci U S A 2006; 103:16562-7. [PMID: 17056716 PMCID: PMC1637621 DOI: 10.1073/pnas.0603511103] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synaptic vesicle (SV) exocytosis mediating neurotransmitter release occurs spontaneously at low intraterminal calcium concentrations and is stimulated by a rise in intracellular calcium. Exocytosis is compensated for by the reformation of vesicles at plasma membrane and endosomes. Although the adaptor complex AP-3 was proposed to be involved in the formation of SVs from endosomes, whether its function has an indirect effect on exocytosis remains unknown. Using mocha mice, which are deficient in functional AP-3, we identify an AP-3-dependent tetanus neurotoxin-resistant asynchronous release that can be evoked at hippocampal mossy fiber (MF) synapses. Presynaptic targeting of the tetanus neurotoxin-resistant vesicle soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) is lost in mocha hippocampal MF terminals, whereas the localization of synaptobrevin 2 is unaffected. In addition, quantal release in mocha cultures is more frequent and more sensitive to sucrose. We conclude that lack of AP-3 results in more constitutive secretion and loss of an asynchronous evoked release component, suggesting an important function of AP-3 in regulating SV exocytosis at MF terminals.
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Affiliation(s)
- Anita Scheuber
- *Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie–Paris 6, Unité Mixte de Recherche 739, Cortex and Epilepsy, F-75013 Paris, France
| | - Rachel Rudge
- Membrane Traffic in Neuronal and Epithelial Morphogenesis, Institut National de la Santé et de la Recherche Médicale Avenir Team, F-75005 Paris, France
- Institut Jacques Monod, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7592, Université Paris 6, Université Paris 7, F-75005 Paris, France
| | - Lydia Danglot
- Membrane Traffic in Neuronal and Epithelial Morphogenesis, Institut National de la Santé et de la Recherche Médicale Avenir Team, F-75005 Paris, France
- Institut Jacques Monod, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7592, Université Paris 6, Université Paris 7, F-75005 Paris, France
| | - Graca Raposo
- Structure and Membrane Compartments, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 144, Institut Curie, F-75005 Paris, France; and
| | - Thomas Binz
- Institute of Biochemistry, Medical School Hannover, D-30625 Hannover, Germany
| | - Jean-Christophe Poncer
- *Institut National de la Santé et de la Recherche Médicale, Université Pierre et Marie Curie–Paris 6, Unité Mixte de Recherche 739, Cortex and Epilepsy, F-75013 Paris, France
| | - Thierry Galli
- Membrane Traffic in Neuronal and Epithelial Morphogenesis, Institut National de la Santé et de la Recherche Médicale Avenir Team, F-75005 Paris, France
- To whom correspondence should be addressed. E-mail:
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