Calmodulin regulates Cav3 T-type channels at their gating brake

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dc.contributor.authorChemin, Jean
dc.contributor.authorTaiakina, Valentina
dc.contributor.authorMonteil, Arnaud
dc.contributor.authorPiazza, Michael
dc.contributor.authorGuan, Wendy
dc.contributor.authorStephens, Robert F.
dc.contributor.authorKitmitto, Ashraf
dc.contributor.authorPang, Zhiping P.
dc.contributor.authorDolphin, Annette C.
dc.contributor.authorPerez-Reyes, Edward
dc.contributor.authorDieckmann, Thorsten
dc.contributor.authorGuillemette, J. Guy
dc.contributor.authorSpafford, J. David
dc.date.accessioned2018-05-04T19:29:06Z
dc.date.available2018-05-04T19:29:06Z
dc.date.issued2017-12-08
dc.descriptionThis research was originally published in the Journal of Biological Chemistry. Chemin, J., Taiakina, V., Monteil, A., Piazza, M., Guan, W., Stephens, R. F., … Spafford, J. D. Calmodulin regulates Cav3 T-type channels at their gating brake. J. Biol. Chem. 2017; 292, 20010-20031. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.en
dc.description.abstractCalcium (Cav1 and Cav2) and sodium channels possess homologous CaM-binding motifs, known as IQ motifs in their C termini, which associate with calmodulin (CaM), a universal calcium sensor. Cav3 T-type channels, which serve as pacemakers of the mammalian brain and heart, lack a C-terminal IQ motif. We illustrate that T-type channels associate with CaM using co-immunoprecipitation experiments and single particle cryo-electron microscopy. We demonstrate that protostome invertebrate (LCav3) and human Cav3.1, Cav3.2, and Cav3.3 T-type channels specifically associate with CaM at helix 2 of the gating brake in the I–II linker of the channels. Isothermal titration calorimetry results revealed that the gating brake and CaM bind each other with high-nanomolar affinity. We show that the gating brake assumes a helical conformation upon binding CaM, with associated conformational changes to both CaM lobes as indicated by amide chemical shifts of the amino acids of CaM in 1H-15N HSQC NMR spectra. Intact Ca2+-binding sites on CaM and an intact gating brake sequence (first 39 amino acids of the I–II linker) were required in Cav3.2 channels to prevent the runaway gating phenotype, a hyperpolarizing shift in voltage sensitivities and faster gating kinetics. We conclude that the presence of high-nanomolar affinity binding sites for CaM at its universal gating brake and its unique form of regulation via the tuning of the voltage range of activity could influence the participation of Cav3 T-type channels in heart and brain rhythms. Our findings may have implications for arrhythmia disorders arising from mutations in the gating brake or CaM.en
dc.description.sponsorshipHeart and Stroke Foundation of Canada grant-in-aiden
dc.description.sponsorshipNatural Sciences and Engineering Research Council of Canada Discovery grantsen
dc.description.sponsorshipBritish Heart Foundationen
dc.description.sponsorshipLabEx “Ion Channel Science and Therapeutics” and ANR-10-BLAN-1601en
dc.description.sponsorshipNational Institutes of Health Grant NS067456en
dc.description.sponsorshipNSERC Canada Graduate Scholarshipen
dc.description.sponsorshipResearch incentive funds from University of Waterlooen
dc.identifier.urihttp://dx.doi.org/10.1074/jbc.M117.807925
dc.identifier.urihttp://hdl.handle.net/10012/13235
dc.language.isoenen
dc.publisherAmerican Society for Biochemistry and Molecular Biologyen
dc.rightsAttribution 4.0 International*
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/*
dc.subjectcalcium channelen
dc.subjectcircular dichroism (CD)en
dc.subjectcryo-electron microscopyen
dc.subjectgatingen
dc.subjectisothermal titration calorimetry (ITC)en
dc.subjectnuclear magnetic resonance (NMR)en
dc.subjectpatch clampen
dc.subjectshort hairpin RNA (shRNA)en
dc.titleCalmodulin regulates Cav3 T-type channels at their gating brakeen
dc.typeArticleen
dcterms.bibliographicCitationChemin, J., Taiakina, V., Monteil, A., Piazza, M., Guan, W., Stephens, R. F., … Spafford, J. D. (2017). Calmodulin regulates Cav3 T-type channels at their gating brake. Journal of Biological Chemistry, 292(49), 20010–20031. https://doi.org/10.1074/jbc.M117.807925en
uws.contributor.affiliation1Faculty of Scienceen
uws.contributor.affiliation2Chemistryen
uws.peerReviewStatusRevieweden
uws.scholarLevelFacultyen
uws.typeOfResourceTexten

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