INSERM U641, Marseille, France.
Neuron. 2010 Jul 29;67(2):268-79. doi: 10.1016/j.neuron.2010.06.024.
Acidification of synaptic vesicles by the vacuolar proton ATPase is essential for loading with neurotransmitter. Debated findings have suggested that V-ATPase membrane domain (V0) also contributes to Ca(2+)-dependent transmitter release via a direct role in vesicle membrane fusion, but the underlying mechanisms remain obscure. We now report a direct interaction between V0 c-subunit and the v-SNARE synaptobrevin, constituting a molecular link between the V-ATPase and SNARE-mediated fusion. Interaction domains were mapped to the membrane-proximal domain of VAMP2 and the cytosolic 3.4 loop of c-subunit. Acute perturbation of this interaction with c-subunit 3.4 loop peptides did not affect synaptic vesicle proton pump activity, but induced a substantial decrease in neurotransmitter release probability, inhibiting glutamatergic as well as cholinergic transmission in cortical slices and cultured sympathetic neurons, respectively. Thus, V-ATPase may ensure two independent functions: proton transport by a fully assembled V-ATPase and a role in SNARE-dependent exocytosis by the V0 sector.
通过液泡质子 ATP 酶使突触小泡酸化对于神经递质的装载至关重要。有争议的发现表明，V-ATPase 膜结构域（V0）也通过在囊泡膜融合中的直接作用，有助于 Ca2+依赖性递质释放，但潜在的机制仍不清楚。我们现在报告了 V0 c 亚基与 v-SNARE 突触融合蛋白之间的直接相互作用，构成了 V-ATPase 和 SNARE 介导融合之间的分子联系。相互作用域被映射到 VAMP2 的膜近端结构域和 c 亚基的胞质 3.4 环。用 c 亚基 3.4 环肽对这种相互作用的急性干扰不会影响突触小泡质子泵的活性，但会导致神经递质释放概率显著降低，分别抑制皮质切片和培养的交感神经元中的谷氨酸能和胆碱能传递。因此，V-ATPase 可能确保两种独立的功能：完全组装的 V-ATPase 的质子运输和 V0 区在 SNARE 依赖性胞吐作用中的作用。
