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Calmodulin mutations causing catecholaminergic polymorphic ventricular tachycardia confer opposing functional and biophysical molecular changes

Sondergaard, Mads T.; Sorensen, Anders B.; Skov, Louise L.; Kjaer-Sorensen, Kasper; Bauer, Mikael LU ; Nyegaard, Mette; Linse, Sara LU ; Oxvig, Claus and Overgaard, Michael T. (2015) In The FEBS Journal 282(4). p.803-816
Abstract
Calmodulin (CaM) is the central mediator of intracellular Ca2+ signalling in cardiomyocytes, where it conveys the intricate Ca2+ transients to the proteins controlling cardiac contraction. We recently linked two separate mutations in CaM (N53I and N97S) to dominantly inherited catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmic disorder in which exercise or acute emotion can lead to syncope and sudden cardiac death. Given the ubiquitous presence of CaM in all eukaryote cells, it is particular intriguing that carriers of either mutation show no additional symptoms. Here, we investigated the effects of the CaM CPVT mutations in a zebrafish animal model. Three-day-old embryos injected with either CaM mRNA showed no... (More)
Calmodulin (CaM) is the central mediator of intracellular Ca2+ signalling in cardiomyocytes, where it conveys the intricate Ca2+ transients to the proteins controlling cardiac contraction. We recently linked two separate mutations in CaM (N53I and N97S) to dominantly inherited catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmic disorder in which exercise or acute emotion can lead to syncope and sudden cardiac death. Given the ubiquitous presence of CaM in all eukaryote cells, it is particular intriguing that carriers of either mutation show no additional symptoms. Here, we investigated the effects of the CaM CPVT mutations in a zebrafish animal model. Three-day-old embryos injected with either CaM mRNA showed no detectable pathologies or developmental abnormalities. However, embryos injected with CPVT CaM mRNA displayed increased heart rate compared to wild-type CaM mRNA under -adrenergic stimulation, demonstrating a conserved dominant cardiac specific effect between zebrafish and human carriers of these mutations. Motivated by the highly similar physiological phenotypes, we compared the effects of the N53I and N97S mutations on the biophysical and functional properties of CaM. Surprisingly, the mutations have opposing effects on CaM C-lobe Ca2+ binding affinity and kinetics, and changes to the CaM N-lobe Ca2+ binding are minor and specific to the N53I mutation. Furthermore, both mutations induce differential perturbations to structure and stability towards unfolding. Our results suggest different molecular disease mechanisms for the CPVT (N53I and N97S mutations) and strongly support that cardiac contraction is the physiological process most sensitive to CaM integrity. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
arrhythmia, calcium binding, calcium signalling, calmodulin mutations, protein folding
in
The FEBS Journal
volume
282
issue
4
pages
803 - 816
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • wos:000350288300012
  • scopus:84923176771
ISSN
1742-464X
DOI
10.1111/febs.13184
language
English
LU publication?
yes
id
45cd8f32-048c-40af-b7da-8dce715192a5 (old id 5303937)
date added to LUP
2015-04-27 11:18:12
date last changed
2017-08-27 05:00:57
@article{45cd8f32-048c-40af-b7da-8dce715192a5,
  abstract     = {Calmodulin (CaM) is the central mediator of intracellular Ca2+ signalling in cardiomyocytes, where it conveys the intricate Ca2+ transients to the proteins controlling cardiac contraction. We recently linked two separate mutations in CaM (N53I and N97S) to dominantly inherited catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmic disorder in which exercise or acute emotion can lead to syncope and sudden cardiac death. Given the ubiquitous presence of CaM in all eukaryote cells, it is particular intriguing that carriers of either mutation show no additional symptoms. Here, we investigated the effects of the CaM CPVT mutations in a zebrafish animal model. Three-day-old embryos injected with either CaM mRNA showed no detectable pathologies or developmental abnormalities. However, embryos injected with CPVT CaM mRNA displayed increased heart rate compared to wild-type CaM mRNA under -adrenergic stimulation, demonstrating a conserved dominant cardiac specific effect between zebrafish and human carriers of these mutations. Motivated by the highly similar physiological phenotypes, we compared the effects of the N53I and N97S mutations on the biophysical and functional properties of CaM. Surprisingly, the mutations have opposing effects on CaM C-lobe Ca2+ binding affinity and kinetics, and changes to the CaM N-lobe Ca2+ binding are minor and specific to the N53I mutation. Furthermore, both mutations induce differential perturbations to structure and stability towards unfolding. Our results suggest different molecular disease mechanisms for the CPVT (N53I and N97S mutations) and strongly support that cardiac contraction is the physiological process most sensitive to CaM integrity.},
  author       = {Sondergaard, Mads T. and Sorensen, Anders B. and Skov, Louise L. and Kjaer-Sorensen, Kasper and Bauer, Mikael and Nyegaard, Mette and Linse, Sara and Oxvig, Claus and Overgaard, Michael T.},
  issn         = {1742-464X},
  keyword      = {arrhythmia,calcium binding,calcium signalling,calmodulin mutations,protein folding},
  language     = {eng},
  number       = {4},
  pages        = {803--816},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {The FEBS Journal},
  title        = {Calmodulin mutations causing catecholaminergic polymorphic ventricular tachycardia confer opposing functional and biophysical molecular changes},
  url          = {http://dx.doi.org/10.1111/febs.13184},
  volume       = {282},
  year         = {2015},
}