Ca2+ uptake into the sarcoplasmic reticulum (SR) is mediated by the cardiac SR Ca2+‐ATPase (Serca2a) and regulated by Pln. 25Serca2a is an important regulator of intracellular Ca2+ signaling in the heart, and its decreased expression and activity are implicated in heart failure.26 We performed immunoblotting analyses to assess the protein levels of Serca2a and Pln and the phosphorylation state of Pln (Figure 4A). The gene discussed is PLN; the disease is heart failure.