FIGURE 4.

A, confocal image of a permeabilized cardiac trabeculum after exchange with a recombinant fluorescently labeled rRLC. B, fluorescent intensity across sarcomeres measured before and after a secondary exchange with an unlabeled recombinant RLC. C, exchange efficiency calculated from integrating fluorescent intensity before and after secondary exchange. Data presented are an average ± S.E. of n = 3 separate exchange procedures on permeabilized trabeculae. D, calculated RLC phosphorylation changes after trabeculae have undergone exchange with differently phosphorylated rRLC species. Control, the native left ventricular phosphorylation level of RLC (n = 12). Control Exchange, the calculated phosphorylation level of trabeculae that have undergone exchange with rRLC that is similarly phosphorylated to native RLC. Enriched RLC Phos, the RLC phosphorylation after exchange with enriched rRLC species. Depleted RLC Phos, the effect on trabecular phosphorylation after exchange with dephosphorylated rRLC species. Error bars are calculated from S.E. values of exchange efficiencies.