Connexin 43-serine 282 modulates serine 279 phosphorylation in cardiomyocytes

Connexin 43 (Cx43) phosphorylation plays a pivotal role in cardiac electrical and contractile performance. In a previous study we have found that Cx43 phosphorylation at serine 282 (pS282) regulates cardiomyocyte survival. Considering that both sites are altered simultaneously in many studies, we designed this study to identify the status of 5279 phosphorylation upon pS282 manipulation. In heterozygous mice with 5282 gene substituted with alanine (S282A), we found ventricular arrhythmias with inhibition of Cx43 phosphorylation at both 5282 and 5279 in the hearts. In cultured neonatal rat ventricular myocytes (NRVMs), transfection of virus carrying S282A mutant also blocked Cx43 phosphorylation at both S279/282 and gap junction coupling, while expression of wild-type Cx43 or S279A did not. Further, NRVMs transfected with 5282 phospho-mimicking mutant substituted with aspartate or treated with ATP exhibited promotions of Cx43 phosphorylation at S279/282 and intercellular communication. Therefore, this study demonstrated a regulatory role of Cx43-S282 on 5279 phosphorylation in cardiomyocytes, and suggested an involvement of 5279 in the Cx43-5282 mediated cardiomyocyte homeostasis. (C) 2019 Elsevier Inc. All rights reserved.