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Calmodulin regulates Ca(v)3 T-type channels at their gating brake

Calcium (Ca(v)1 and Ca(v)2) 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. Ca(v)3 T-type channels, which serve as pacemakers of the mammalian brain and heart, lack a C-terminal IQ mo...

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Autores principales: Chemin, Jean, Taiakina, Valentina, Monteil, Arnaud, Piazza, Michael, Guan, Wendy, Stephens, Robert F., Kitmitto, Ashraf, Pang, Zhiping P., Dolphin, Annette C., Perez-Reyes, Edward, Dieckmann, Thorsten, Guillemette, Joseph Guy, Spafford, J. David
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723990/
https://www.ncbi.nlm.nih.gov/pubmed/28972185
http://dx.doi.org/10.1074/jbc.M117.807925
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author Chemin, Jean
Taiakina, Valentina
Monteil, Arnaud
Piazza, Michael
Guan, Wendy
Stephens, Robert F.
Kitmitto, Ashraf
Pang, Zhiping P.
Dolphin, Annette C.
Perez-Reyes, Edward
Dieckmann, Thorsten
Guillemette, Joseph Guy
Spafford, J. David
author_facet Chemin, Jean
Taiakina, Valentina
Monteil, Arnaud
Piazza, Michael
Guan, Wendy
Stephens, Robert F.
Kitmitto, Ashraf
Pang, Zhiping P.
Dolphin, Annette C.
Perez-Reyes, Edward
Dieckmann, Thorsten
Guillemette, Joseph Guy
Spafford, J. David
author_sort Chemin, Jean
collection PubMed
description Calcium (Ca(v)1 and Ca(v)2) 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. Ca(v)3 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 (LCa(v)3) and human Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3 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 (1)H-(15)N HSQC NMR spectra. Intact Ca(2+)-binding sites on CaM and an intact gating brake sequence (first 39 amino acids of the I–II linker) were required in Ca(v)3.2 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 Ca(v)3 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.
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spelling pubmed-57239902017-12-11 Calmodulin regulates Ca(v)3 T-type channels at their gating brake Chemin, Jean Taiakina, Valentina Monteil, Arnaud Piazza, Michael Guan, Wendy Stephens, Robert F. Kitmitto, Ashraf Pang, Zhiping P. Dolphin, Annette C. Perez-Reyes, Edward Dieckmann, Thorsten Guillemette, Joseph Guy Spafford, J. David J Biol Chem Neurobiology Calcium (Ca(v)1 and Ca(v)2) 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. Ca(v)3 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 (LCa(v)3) and human Ca(v)3.1, Ca(v)3.2, and Ca(v)3.3 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 (1)H-(15)N HSQC NMR spectra. Intact Ca(2+)-binding sites on CaM and an intact gating brake sequence (first 39 amino acids of the I–II linker) were required in Ca(v)3.2 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 Ca(v)3 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. American Society for Biochemistry and Molecular Biology 2017-12-08 2017-09-25 /pmc/articles/PMC5723990/ /pubmed/28972185 http://dx.doi.org/10.1074/jbc.M117.807925 Text en © 2017 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version free via Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0) .
spellingShingle Neurobiology
Chemin, Jean
Taiakina, Valentina
Monteil, Arnaud
Piazza, Michael
Guan, Wendy
Stephens, Robert F.
Kitmitto, Ashraf
Pang, Zhiping P.
Dolphin, Annette C.
Perez-Reyes, Edward
Dieckmann, Thorsten
Guillemette, Joseph Guy
Spafford, J. David
Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title_full Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title_fullStr Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title_full_unstemmed Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title_short Calmodulin regulates Ca(v)3 T-type channels at their gating brake
title_sort calmodulin regulates ca(v)3 t-type channels at their gating brake
topic Neurobiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723990/
https://www.ncbi.nlm.nih.gov/pubmed/28972185
http://dx.doi.org/10.1074/jbc.M117.807925
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