Synergistic regulation of fusion pore opening and dilation by SNARE and synaptotagmin-1  

作　　者：Kaiju Li Kaiyu Li Jiaqi Fan Xing Zhang Chengyan Tao Yijuan Xiang Lele Cui Hao Li Minghan Li Yanjing Zhang Jia Geng Ying Lai 

机构地区：[1]National Clinical Research Center for Geriatrics,State Key Laboratory of Biotherapy and Collaborative Innovation Center of Biotherapy,West China Hospital,Sichuan University,Chengdu 610041,China [2]Department of Laboratory Medicine,State Key Laboratory of Biotherapy and Cancer Center,West China Hospital,Sichuan University and Collaborative Innovation Center,Chengdu 610041,China [3]Tianfu Jincheng Laboratory,City of Future Medicine,Chengdu 641400,China

出　　处：《Journal of Molecular Cell Biology》2024年第4期17-30,共14页分子细胞生物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(31900688 and 32170686 to Y.L.);Sichuan University West China Hospital(ZYYC21007 and Z2021JC007 to Y.L.);the National Key Research and Development Program of China(2022YFB3205600 to J.G.).

摘　　要：Fusion pore opening is a transient intermediate state of synaptic vesicle exocytosis,which is highly dynamic and precisely regulated by the soluble N-ethylmaleimide-sensitive factor attachment protein receptor(SNARE)complex and synaptotagmin-1(Syt1).Yet,the regulatory mechanism is not fully understood.In this work,using single-channel membrane fusion electrophysiology,we determined that SNAREpins are important for driving fusion pore opening and dilation but incapable of regulating the dynamics.When Syt1 was added,the closing frequency of fusion pores significantly increased,while the radius of fusion pores mildly decreased.In response to Ca^(2+),SNARE/Syt1 greatly increased the radius of fusion pores and reduced their closing frequency.Moreover,the residue F349 in the C2B domain of Syt1,which mediates Syt1 oligomerization,was required for clamping fusion pore opening in the absence of Ca^(2+),probably by extending the distance between the two membranes.Finally,in Ca^(2+)-triggered fusion,the primary interface between SNARE and Syt1 plays a critical role in stabilizing and dilating the fusion pore,while the polybasic region of Syt1 C2B domain has a mild effect on increasing the radius of the fusion pore.In summary,our results suggest that Syt1,SNARE,and the anionic membrane synergically orchestrate the dynamics of fusion pore opening in synaptic vesicle exocytosis.

关 键 词：SNARE synaptotagmin-1 fusion pore vesicle exocytosis 

分 类 号：O57[理学—粒子物理与原子核物理]