SNARE protein recycling by αSNAP and βSNAP supports synaptic vesicle priming.
Neurotransmitter release proceeds by Ca(2+)-triggered, SNARE-complex-dependent synaptic vesicle fusion. After fusion, the ATPase NSF and its cofactors α- and βSNAP disassemble SNARE complexes, thereby recycling individual SNAREs for subsequent fusion reactions. We examined the effects of genetic perturbation of α- and βSNAP expression on synaptic vesicle exocytosis, employing a new Ca(2+) uncaging protocol to study synaptic vesicle trafficking, priming, and fusion in small glutamatergic synapses of hippocampal neurons. By characterizing this protocol, we show that synchronous and asynchronous transmitter release involve different Ca(2+) sensors and are not caused by distinct releasable vesicle pools, and that tonic transmitter release is due to ongoing priming and fusion of new synaptic vesicles during high synaptic activity. Our analysis of α- and βSNAP deletion mutant neurons shows that the two NSF cofactors support synaptic vesicle priming by determining the availability of free SNARE components, particularly during phases of high synaptic activity.
Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany.
Andrea
A
Burgalossi
Sangyong
S
Jung
Guido
G
Meyer
Wolf J
WJ
Jockusch
Olaf
O
Jahn
Holger
H
Taschenberger
Vincent M
VM
O'Connor
Tei-ichi
T
Nishiki
Masami
M
Takahashi
Nils
N
Brose
Jeong-Seop
JS
Rhee
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism; D018408:Patch-Clamp Techniques; D050600:SNARE Proteins / Q000502:physiology*; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins / Q000502:physiology*; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000502:physiology*; D050863:Synaptotagmin I / Q000235:genetics / Q000502:physiology
D018377:Neurotransmitter Agents; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D050863:Synaptotagmin I; C494311:Syt1 protein, mouse; D018698:Glutamic Acid; D002118:Calcium