2-Aminoethoxydiphenyl Borate Potentiates CRAC Current by Directly Dilating the Pore of Open Orai1.
2-Aminoethoxydiphenyl Borate Potentiates CRAC Current by Directly Dilating the Pore of Open Orai1.
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DOI：
10.1038/srep29304
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发表时间：
2016-07-04
影响因子：
4.6
通讯作者：
Xu T
中科院分区：
文献类型：
--
作者：
Xu X;Ali S;Li Y;Yu H;Zhang M;Lu J;Xu T
2-氨基乙氧基二苯基硼酸酯（2-APB）对Ca 2+释放激活的Ca 2+（CRAC）通道的增强电流（Ip）。对这种调节机制的准确研究将揭示STIM 1依赖性通道门控是如何增强的，并有利于未来免疫增强剂的开发。在这里，我们直接探测了CRAC通道的孔径，发现2-APB将STIM 1激活的Orai 1的孔径从3.8 μ m扩大到4.6 μ m。我们证明了具有小尺寸的离子，即，Ca ~（2+）和Na ~+介导了2-APB对野生型（WT）Orai 1窄孔径通道的显著诱导作用，而对Orai 1-V102 C/A/G突变体大孔径通道的诱导作用减弱或不诱导。相反，大Cs+离子阻断WT通道，而显示大的2-APB诱导的Ipon孔扩大的Orai 1-V102 C/A/G突变体通道，并且在具有中等孔径的Orai 1-V102 C上增强比率最高。此外，我们表明，2-APB增强Cs+电流组成型活性Orai 1-V102 C/A/G突变体的STIM 1独立。我们的数据表明，2-APB直接扩张开放的Orai 1通道的孔径，离子大小和孔径共同决定Ipon CRAC通道的振幅，Ipon CRAC通道的产生需要Orai 1的开放状态，而不是STIM 1本身。
2-Aminoethoxydiphenyl borate (2-APB) elicits potentiation current (Ip) on Ca2+release-activated Ca2+(CRAC) channels. An accurate investigation into this modulation mechanism would reveal how STIM1-dependent channel gating is enhanced and benefit the future immune enhancer development. Here, we directly probed the pore diameter of CRAC channels and found that 2-APB enlarged the pore size of STIM1-activated Orai1 from 3.8 to 4.6 Å. We demonstrated that ions with small sizes, i.e., Ca2+and Na+, mediated prominent 2-APB-inducedIpon the wildtype (WT) Orai1 channels of narrow pore sizes, while conducted decreased or noIpon Orai1-V102C/A/G mutant channels with enlarged pore diameters. On the contrary, large Cs+ions blocked the WT channels, while displayed large 2-APB inducedIpon pore-enlarged Orai1-V102C/A/G mutant channels and the potentiation ratio was highest on Orai1-V102C with an intermediate pore size. Furthermore, we showed that 2-APB potentiated Cs+current on constitutively active Orai1-V102C/A/G mutants independent of STIM1. Our data suggest that 2-APB directly dilates the pore of open Orai1 channels, both ion size and pore diameter jointly determine the amplitude ofIpon CRAC channels and the generation ofIprequires the open state of Orai1, not STIM1 itself.