SNAP-25/syntaxin 1A complex functionally modulates neurotransmitter γ-aminobutyric acid reuptake
SNAP-25/syntaxin 1A complex functionally modulates neurotransmitter γ-aminobutyric acid reuptake
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DOI：
10.1074/jbc.m601382200
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发表时间：
2006-09-22
影响因子：
4.8
通讯作者：
Pei, Gang
中科院分区：
文献类型：
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作者：
Fan, Hua-Ping;Fan, Feng-Juan;Pei, Gang
神经递质γ-氨基丁酸（GABA）释放到突触裂缝是由可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）复合物的形成介导的，该复合物包括两个靶SNARE突触融合蛋白1A和SNAP-25以及一个囊泡SNARE VAMP-2。靶SNARE突触融合蛋白1A和SNAP-25形成异二聚体，即SNARE复合物的推定中间体。神经递质GABA通过其转运体的再摄取功能从突触间隙清除，从而终止突触后信号传导。Syntaxin 1A直接与神经元GABA转运蛋白GAT-1结合并抑制其再摄取功能。然而，其他SNARE蛋白或SNARE复合物是否调节GABA再摄取仍然未知。在这里，我们证明，SNAP-25有效地抑制GAT-1的再摄取功能，在syntaxin 1A的存在。这种抑制依赖于SNAP-25/syntaxin 1A复合物的形成。突触融合蛋白1A的H3结构域被鉴定为SNAP-25和GAT-1的结合位点。SNAP-25与syntaxin 1A的结合大大增强了syntaxin 1A与GAT-1的物理相互作用，并显著增强了syntaxin 1A介导的GAT-1再摄取功能的抑制。此外，促进SNAP-25与突触融合蛋白1A结合以形成SNARE复合物的一氧化氮也增强突触融合蛋白1A与GAT-1的相互作用并抑制GAT-1对GABA的再摄取。因此，我们的研究结果描绘了一个进一步的分子机制，通过一个目标SNARE复杂的GABA再摄取的调节，并建议GABA的释放和再摄取之间的直接协调。
Neurotransmitter gamma-aminobutyric acid (GABA) release to the synaptic clefts is mediated by the formation of a soluble N-ethylmaleimidesensitive factor attachment protein receptor (SNARE) complex, which includes two target SNAREs syntaxin 1A and SNAP-25 and one vesicle SNARE VAMP-2. The target SNAREs syntaxin 1A and SNAP-25 form a heterodimer, the putative intermediate of the SNARE complex. Neurotransmitter GABA clearance from synaptic clefts is carried out by the reuptake function of its transporters to terminate the postsynaptic signaling. Syntaxin 1A directly binds to the neuronal GABA transporter GAT-1 and inhibits its reuptake function. However, whether other SNARE proteins or SNARE complex regulates GABA reuptake remains unknown. Here we demonstrate that SNAP-25 efficiently inhibits GAT-1 reuptake function in the presence of syntaxin 1A. This inhibition depends on SNAP-25/syntaxin 1A complex formation. The H3 domain of syntaxin 1A is identified as the binding sites for both SNAP-25 and GAT-1. SNAP-25 binding to syntaxin 1A greatly potentiates the physical interaction of syntaxin 1A with GAT-1 and significantly enhances the syntaxin 1A-mediated inhibition of GAT-1 reuptake function. Furthermore, nitric oxide, which promotes SNAP-25 binding to syntaxin 1A to form the SNARE complex, also potentiates the interaction of syntaxin 1A with GAT-1 and suppresses GABA reuptake by GAT-1. Thus our findings delineate a further molecular mechanism for the regulation of GABA reuptake by a target SNARE complex and suggest a direct coordination between GABA release and reuptake.