International Journal of Molecular Sciences Article Plakophilin-2 Haploinsufficiency Causes Calcium Handling Deficits and Modulates the Cardiac Response Towards Stress Chantal J.M. van Opbergen 1 , Maartje Noorman 1, Anna Pfenniger 2, Jaël S. Copier 1, Sarah H. Vermij 2,3 , Zhen Li 2, Roel van der Nagel 1, Mingliang Zhang 2, Jacques M.T. de Bakker 1,4, Aaron M. Glass 5, Peter J. Mohler 6,7, Steven M. Taffet 5, Marc A. Vos 1, Harold V.M. van Rijen 1, Mario Delmar 2 and Toon A.B. van Veen 1,* 1 Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584CM Utrecht, The Netherlands 2 Division of Cardiology, NYU School of Medicine, New York, NY 10016, USA 3 Institute of Biochemistry and Molecular Medicine, University of Bern, 3012 Bern, Switzerland 4 Department of Medical Biology, Academic Medical Center Amsterdam, 1105AZ Amsterdam, The Netherlands 5 Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY 13210, USA 6 Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine and Wexner Medical Center, Columbus, OH 43210, USA 7 Departments of Physiology & Cell Biology and Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University College of Medicine Wexner Medical Center, Columbus, OH 43210, USA * Correspondence:
[email protected] Received: 1 August 2019; Accepted: 19 August 2019; Published: 21 August 2019 Abstract: Human variants in plakophilin-2 (PKP2) associate with most cases of familial arrhythmogenic cardiomyopathy (ACM). Recent studies show that PKP2 not only maintains intercellular coupling, but also regulates transcription of genes involved in Ca2+ cycling and cardiac rhythm.