Fig. 6.
Effects of WT PLM and its Ser68 mutants on Na+/Ca2+ exchange current (INaCa) in cultured PLM KO myocytes. Adult cardiac myocytes from congenic PLM KO mice were infected with adenovirus expressing either GFP alone, GFP + WT PLM, GFP + PLMS68A, or GFP + PLMS68E. After myocytes had been cultured for 48 h, INaCa was measured as described in methods. Current density-voltage relationships of INaCa (means ± SE) from KO-GFP (□; n = 11), KO-PLM (▴; n = 11), KO-S68A (•; n = 7), and KO-S68E (○; n = 9) myocytes are shown. For comparison, current density-voltage relationships of INaCa from WT (⧫; n = 20) myocytes are also shown. The reversal potential of INaCa in all myocytes examined was approximately −60 mV. Note that INaCa was lower in WT compared with KO-GFP myocytes. In addition, INaCa was suppressed by WT PLM and the PLMS68E mutant but not by the PLMS68A mutant. Error bars are not shown if they fall within the boundaries of the symbol.