Zhang et al. showed that AS-IV activates the cAMP/PKA pathway, increasing phospholamban (PLN) phosphorylation at Ser16 and relieving PLN-mediated inhibition of sarcoplasmic reticulum Ca2+ ATPase 2a, thereby reducing spontaneous Ca2+ release in post-I/R mice and lowering the risk of AF (Zhang et al., 2012). Here, PLN is linked to atrial fibrillation.