Figure 1. MyBP‐C and TnI phosphorylation in TG lines .

A, representative western blots of WT, TnI^PKA−, MyBPC^PKA− and DBL^PKA− cardiac samples demonstrating TnI and/or MyBP‐C phospho‐ablation. PVDF membranes were probed with primary antibodies specific for TnI phosphorylation (Ser23/24), total TnI, MyBP‐C phosphorylation (Ser273, Ser282 or Ser302), total MyBP‐C or HSC70. B, representative Coomasie and Pro‐Q stained cardiac myofibrils from TG and WT lines that were incubated in the presence or absence of the catalytic subunit of PKA (see Methods). C, quantification of MyBP‐C, TnI and troponin T phosphorylation from cardiac myofibrils for each line with or without PKA incubation. The intensity of the Pro‐Q band was normalized to the Coomassie band intensity and non‐PKA treated WT myofibril protein phosphorylation was set as 1. Myofibrils were isolated from six hearts for each mouse line. D, representative western blots of WT, TnI^PKA−, MyBPC^PKA− and DBL^PKA− cardiac ventricular samples demonstrating PLB phosphorylation. PVDF membranes were probed with primary antibodies specific for PLB phosphorylation (Ser16) in the absence (–) or presence (+) of dobutamine administration. E, quantification of PLB phosphorylation from cardiac samples for each line with or without dobutamine administration. PLB phosphorylation was normalized to total PLB protein expression and non‐dobutamine treated WT PLB phosphorylation was set as 1. Ventricular samples were isolated from three or four hearts for each mouse line.