The expression and phosphorylation of calcium handling proteins in 4-month-old control and mdx hearts. (A and B) Western blot analysis of SERCA2a, PLB, NCX1, RyR2, Cav1.2α1c, Cav1.2β1, and Cav1.2β2 in 4-month-old mdx hearts was compared with that 4-month-old control hearts. (C–F) Western analysis of Cav1.2α1c phosphorylated at Ser1928 (C), RyR2 phosphorylated at Ser2815 and Ser2809 (D), PLB phosphorylated at Ser16 and Thr17 at baseline, and after ISO stimulation (E). The averaged phosphorylation level of these proteins is shown in (F). Student's t-test was done for each protein in (B) and two-way ANOVAs for phosphorylated proteins in (F).