Insights into CLC-0’s Slow-Gating from Intracellular Proton Inhibition

Hwoi Chan Kwon, Robert H. Fairclough, Tsung Yu Chen*

*此作品的通信作者

研究成果: Article同行評審

摘要

The opening of the Torpedo CLC-0 chloride (Cl) channel is known to be regulated by two gating mechanisms: fast gating and slow (common) gating. The structural basis underlying the fast-gating mechanism is better understood than that of the slow-gating mechanism, which is still largely a mystery. Our previous study on the intracellular proton (H+i)-induced inhibition of the CLC-0 anionic current led to the conclusion that the inhibition results from the slow-gate closure (also called inactivation). The conclusion was made based on substantial evidence such as a large temperature dependence of the H+i inhibition similar to that of the channel inactivation, a resistance to the H+i inhibition in the inactivation-suppressed C212S mutant, and a similar voltage dependence between the current recovery from the H+i inhibition and the recovery from the channel inactivation. In this work, we further examine the mechanism of the H+i inhibition of wild-type CLC-0 and several mutants. We observe that an anion efflux through the pore of CLC-0 accelerates the recovery from the H+i-induced inhibition, a process corresponding to the slow-gate opening. Furthermore, various inactivation-suppressed mutants exhibit different current recovery kinetics, suggesting the existence of multiple inactivated states (namely, slow-gate closed states). We speculate that protonation of the pore of CLC-0 increases the binding affinity of permeant anions in the pore, thereby generating a pore blockage of ion flow as the first step of inactivation. Subsequent complex protein conformational changes further transition the CLC-0 channel to deeper inactivated states.

原文English
文章編號7796
期刊International Journal Of Molecular Sciences
25
發行號14
DOIs
出版狀態Published - 7月 2024

指紋

深入研究「Insights into CLC-0’s Slow-Gating from Intracellular Proton Inhibition」主題。共同形成了獨特的指紋。

引用此