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Figure 2: (a) Pig cardiac myocyte sarcomere length-tension relationships before and after PKA treatment. PKA-induced phosphorylation markedly steepened the length-tension relationship. (b) An autoradiogram showing radiolabeled phosphate incorporation into pig cardiac myofibrillar proteins (MyBP-C and cTnI) upon PKA treatment. Without PKA treatment, there was no radiolabelled ATP incorporation (data not shown).