Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, D-37075 Göttingen, Germany.
Neuron. 2010 Nov 4;68(3):473-87. doi: 10.1016/j.neuron.2010.09.019.
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.
神经递质释放是通过 Ca(2+)触发、SNARE 复合物依赖性突触囊泡融合来进行的。融合后，ATP 酶 NSF 及其辅助因子 α-SNAP 和 β-SNAP 会拆开 SNARE 复合物，从而使单个 SNARE 循环用于随后的融合反应。我们通过使用新的 Ca(2+)光解笼闭方案研究海马神经元中小谷氨酸能突触中的突触囊泡转运、引发和融合，来研究 α-SNAP 和 β-SNAP 表达的遗传干扰对突触囊泡胞吐作用的影响。通过对该方案进行表征，我们发现同步和异步递质释放涉及不同的 Ca(2+)传感器，而不是由不同的可释放囊泡池引起的，并且持续的引发和融合新的突触囊泡导致了持续的递质释放。我们对 α-SNAP 和 β-SNAP 缺失突变神经元的分析表明，这两种 NSF 辅助因子通过确定游离 SNARE 成分的可用性来支持突触囊泡的引发，尤其是在高突触活动期间。
