RYR2 and Arrhythmia: Cardiac myocytes from mice that were fed a fructose-rich diet exhibited arrhythmias caused by the exacerbation of Ca2+/calmodulin-protein kinase (CaMKII) activity, phosphorylation of ryanodine receptor 2 (RyR2), and sarcoplasmic reticular Ca2+ leakage [41].