Correcting the R165K substitution in the first voltage-sensor of CaV1.1 right-shifts the voltage-dependence of skeletal muscle calcium channel activation.
Yousra El Ghaleb, Marta Campiglio, Bernhard E Flucher
{"title":"Correcting the R165K substitution in the first voltage-sensor of Ca<sub>V</sub>1.1 right-shifts the voltage-dependence of skeletal muscle calcium channel activation.","authors":"Yousra El Ghaleb, Marta Campiglio, Bernhard E Flucher","doi":"10.1080/19336950.2019.1568825","DOIUrl":null,"url":null,"abstract":"<p><p>The voltage-gated calcium channel Ca<sub>V</sub>1.1a primarily functions as voltage-sensor in skeletal muscle excitation-contraction (EC) coupling. In embryonic muscle the splice variant Ca<sub>V</sub>1.1e, which lacks exon 29, additionally function as a genuine L-type calcium channel. Because previous work in most laboratories used a Ca<sub>V</sub>1.1 expression plasmid containing a single amino acid substitution (R165K) of a critical gating charge in the first voltage-sensing domain (VSD), we corrected this substitution and analyzed its effects on the gating properties of the L-type calcium currents in dysgenic myotubes. Reverting K165 to R right-shifted the voltage-dependence of activation by ~12 mV in both Ca<sub>V</sub>1.1 splice variants without changing their current amplitudes or kinetics. This demonstrates the exquisite sensitivity of the voltage-sensor function to changes in the specific amino acid side chains independent of their charge. Our results further indicate the cooperativity of VSDs I and IV in determining the voltage-sensitivity of Ca<sub>V</sub>1.1 channel gating.</p>","PeriodicalId":72555,"journal":{"name":"Channels (Austin, Tex.)","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6380215/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Channels (Austin, Tex.)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1080/19336950.2019.1568825","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The voltage-gated calcium channel CaV1.1a primarily functions as voltage-sensor in skeletal muscle excitation-contraction (EC) coupling. In embryonic muscle the splice variant CaV1.1e, which lacks exon 29, additionally function as a genuine L-type calcium channel. Because previous work in most laboratories used a CaV1.1 expression plasmid containing a single amino acid substitution (R165K) of a critical gating charge in the first voltage-sensing domain (VSD), we corrected this substitution and analyzed its effects on the gating properties of the L-type calcium currents in dysgenic myotubes. Reverting K165 to R right-shifted the voltage-dependence of activation by ~12 mV in both CaV1.1 splice variants without changing their current amplitudes or kinetics. This demonstrates the exquisite sensitivity of the voltage-sensor function to changes in the specific amino acid side chains independent of their charge. Our results further indicate the cooperativity of VSDs I and IV in determining the voltage-sensitivity of CaV1.1 channel gating.