Size matters: Ryanodine receptor cluster size heterogeneity potentiates calcium waves (Biophysical Journal)

Ryanodine receptors (RyRs) mediate calcium (Ca)-induced Ca release (CICR) and intracellular Ca homeostasis. In a cardiac myocyte, RyRs group into clusters of variable size from a few to several hundred RyRs, creating a spatially non-uniform intracellular distribution. It is unclear how heterogeneity of RyR cluster size alters spontaneous sarcoplasmic reticulum (SR) Ca releases (Ca sparks) and arrhythmogenic Ca waves. Here, we tested the impact of heterogeneous RyR cluster size on the initiation of Ca waves.