Association of Botulinum Neurotoxin Serotype A Light Chain with Plasma Membrane-bound SNAP-25
Association of Botulinum Neurotoxin Serotype A Light Chain with Plasma Membrane-bound SNAP-25
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DOI：
10.1074/jbc.m111.224493
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发表时间：
2011-04-29
影响因子：
4.8
通讯作者：
Barbieri, Joseph T.
中科院分区：
文献类型：
--
作者：
Chen, Sheng;Barbieri, Joseph T.
肉毒梭菌神经毒素(BoNTs)裂解SNARE蛋白，后者抑制神经递质小泡与周围神经元质膜的结合和融合。BoNTs由N-端轻链(LC)和C-端重链组成，通过二硫键连接。根据免疫中和，BoNTs有七种血清型(A-G)。尽管BoNT/A与神经元的结合和进入神经元的研究已经进行了相当多的研究，但使BoNT/A有效切割神经元内SNAP-25的细胞内事件却知之甚少。早期的研究表明，细胞内的LC/A结合到神经元的质膜上。在这项研究中，细胞内的LC/A直接将SNAP-25结合到质膜上。固相结合结果表明，SNAP-25的Lc/A的N端残基与SNAP-25的80-110个残基结合，在培养的神经元中也观察到这种结合。LC/A的N端8个氨基酸与SNAP-25的80-110位残基的结合也促进了底物切割。这些发现解释了LC/A如何与质膜上的SNAP-25结合，并为SNAP-25在SNARE复合体中的LC/A切割提供了基础。
The Clostridium botulinum neurotoxins (BoNTs) cleave SNARE proteins, which inhibit binding and thus fusion of neurotransmitter vesicles to the plasma membrane of peripheral neurons. BoNTs comprise an N-terminal light chain (LC) and C-terminal heavy chain, which are linked by a disulfide bond. There are seven serotypes (A-G) of BoNTs based upon immunological neutralization. Although the binding and entry of BoNT/A into neurons has been subjected to considerable investigation, the intracellular events that allow BoNT/A to efficiently cleave SNAP-25 within neurons is less well understood. Earlier studies showed that intracellular LC/A bound to the plasma membrane of neurons. In this study, intracellular LC/A is shown to directly bind SNAP-25 on the plasma membrane. Solid phase binding showed that the N-terminal residues of LC/A bound residues 80-110 of SNAP-25, which was also observed in cultured neurons. Association of the N-terminal 8 amino acids of LC/A and residues 80-110 of SNAP-25 also enhanced substrate cleavage. These findings explain how LC/A associates with SNAP-25 on the plasma membrane and provide a basis for LC/A cleavage of SNAP-25 within the SNARE complex.