2-Aminoethoxydiphenyl Borate Potentiates CRAC Current by Directly Dilating the Pore of Open Orai1.

ABSTRACT: 2-Aminoethoxydiphenyl borate (2-APB) elicits potentiation current (Ip) on Ca(2+) release-activated Ca(2+) (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., Ca(2+) and Na(+), mediated prominent 2-APB-induced Ip on the wildtype (WT) Orai1 channels of narrow pore sizes, while conducted decreased or no Ip on 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 induced Ip

SUBMITTER: Xu X 

PROVIDER: S-EPMC4931693 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature