{"title":"A new polymodal gating model of the proton-activated chloride channel.","authors":"Piao Zhao, Cheng Tang, Yuqin Yang, Zhen Xiao, Samantha Perez-Miller, Heng Zhang, Guoqing Luo, Hao Liu, Yaqi Li, Qingyi Liao, Fan Yang, Hao Dong, Rajesh Khanna, Zhonghua Liu","doi":"10.1371/journal.pbio.3002309","DOIUrl":null,"url":null,"abstract":"The proton-activated chloride (PAC) channel plays critical roles in ischemic neuron death, but its activation mechanisms remain elusive. Here, we interrogated PAC channel gating using its unique bidirectional modulator C77304 as a pharmacological probe. C77304 activated the PAC channel by acting on its proton gating, while simultaneously inhibiting channel activity at higher doses, through interaction with two modulatory sites with different affinities and state-dependence. Excitingly, we revealed that PAC undergoes intrinsic proton gating-independent voltage activation, which was defined by an ion-flux gating mechanism. Scanning-mutagenesis and molecular dynamics simulation confirmed that E181, E257, and E261 in human PAC form the primary proton sensors, as alanine mutations eliminated the channel’s proton gating while sparing the voltage-dependent gating. This proton sensing mechanism was basically conserved among orthologous PAC channels. Collectively, our data unveils the polymodal gating and proton sensing mechanisms in the PAC channel which may inspire potential drug development.","PeriodicalId":20240,"journal":{"name":"PLoS Biology","volume":null,"pages":null},"PeriodicalIF":7.8000,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10529583/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"PLoS Biology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1371/journal.pbio.3002309","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2023/9/1 0:00:00","PubModel":"eCollection","JCR":"Q1","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The proton-activated chloride (PAC) channel plays critical roles in ischemic neuron death, but its activation mechanisms remain elusive. Here, we interrogated PAC channel gating using its unique bidirectional modulator C77304 as a pharmacological probe. C77304 activated the PAC channel by acting on its proton gating, while simultaneously inhibiting channel activity at higher doses, through interaction with two modulatory sites with different affinities and state-dependence. Excitingly, we revealed that PAC undergoes intrinsic proton gating-independent voltage activation, which was defined by an ion-flux gating mechanism. Scanning-mutagenesis and molecular dynamics simulation confirmed that E181, E257, and E261 in human PAC form the primary proton sensors, as alanine mutations eliminated the channel’s proton gating while sparing the voltage-dependent gating. This proton sensing mechanism was basically conserved among orthologous PAC channels. Collectively, our data unveils the polymodal gating and proton sensing mechanisms in the PAC channel which may inspire potential drug development.
期刊介绍:
PLOS Biology is an open-access, peer-reviewed general biology journal published by PLOS, a nonprofit organization of scientists and physicians dedicated to making the world's scientific and medical literature freely accessible. The journal publishes new articles online weekly, with issues compiled and published monthly.
ISSN Numbers:
eISSN: 1545-7885
ISSN: 1544-9173