The Arrhythmogenic Calmodulin Mutation D129G Dysregulates Cell Growth, Calmodulin-dependent Kinase II Activity, and Cardiac Function in Zebrafish

Martin W. Berchtold; Triantafyllos Zacharias; Katarzyna Kulej; Kevin Wang; Raffaela Torggler; Thomas Jespersen; Jau-Nian Chen; Martin R. Larsen; Jonas M. la Cour

doi:10.1074/jbc.M116.758680

The Arrhythmogenic Calmodulin Mutation D129G Dysregulates Cell Growth, Calmodulin-dependent Kinase II Activity, and Cardiac Function in Zebrafish*

From the ^‡Department of Biology and
the ^‖Danish Arrhythmia Research Centre, University of Copenhagen, 2100 Copenhagen, Denmark,
the ^§Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark, and
the ^¶Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095

↵1 To whom correspondence may be addressed: Dept. of Biology, University of Copenhagen, Denmark, Universitetsparken 13, 2100 Copenhagen, Denmark. Tel.: 45-24467173; E-mail: mabe{at}bio.ku.dk.
↵2 To whom correspondence may be addressed: Dept. of Biology, University of Copenhagen, Denmark, Universitetsparken 13, 2100 Copenhagen, Denmark. Tel.: 45-24467397; E-mail: jonas{at}bio.ku.dk.

Edited by Henrik Dohlman

Abstract

Calmodulin (CaM) is a Ca²⁺ binding protein modulating multiple targets, several of which are associated with cardiac pathophysiology. Recently, CaM mutations were linked to heart arrhythmia. CaM is crucial for cell growth and viability, yet the effect of the arrhythmogenic CaM mutations on cell viability, as well as heart rhythm, remains unknown, and only a few targets with relevance for heart physiology have been analyzed for their response to mutant CaM. We show that the arrhythmia-associated CaM mutants support growth and viability of DT40 cells in the absence of WT CaM except for the long QT syndrome mutant CaM D129G. Of the six CaM mutants tested (N53I, F89L, D95V, N97S, D129G, and F141L), three showed a decreased activation of Ca²⁺/CaM-dependent kinase II, most prominently the D129G CaM mutation, which was incapable of stimulating Thr²⁸⁶ autophosphorylation. Furthermore, the CaM D129G mutation led to bradycardia in zebrafish and an arrhythmic phenotype in a subset of the analyzed zebrafish.

Footnotes

↵* This work was supported by funds from the Danish Heart Foundation (to J. M. L. C. and M. W. B.), AP Møller Lægefonden (to J. M. L. C.), and the Nilssons, Marshall, Willumsen, and Danielsen Foundations (to M. W. B.) and by Danish Research Council Grant FSS4004-00560 (to M. W. B. and J. M. L. C.). The authors declare that they have no conflicts of interest with the contents of this article.