Phosphorylation of RyR2 Ser‐2814 by CaMKII mediates β1‐adrenergic stress induced Ca<sup>2+</sup>‐leak from the sarcoplasmic reticulum
Maria J. Baier, Jannis Noack, Mark Tilmann Seitz, Lars S. Maier, Stefan Neef
Abstract
Adrenergic stimulation, while being the central mechanism of cardiac positive inotropy, is a universally acknowledged inductor of undesirable sarcoplasmic reticulum (SR) Ca 2+ leak. However, the exact mechanisms for this remained unspecified so far. This study shows that Ca 2+ /calmodulin‐dependent protein kinase II (CaMKII)‐specific phosphorylation of ryanodine receptor type 2 at Ser‐2814 is the pivotal mechanism by which SR Ca 2+ leak develops downstream of β1‐adrenergic stress by increase of the leak/load relationship. Cardiomyocytes with a Ser‐2814 phosphoresistant mutation (S2814A) were protected from isoproterenol‐induced SR Ca 2+ leak and consequently displayed improved postrest potentiation of systolic Ca 2+ release under adrenergic stress compared to littermate wild‐type cells.