Rem inhibits EC coupling in FDB fibers without affecting intramembrane charge movement. Representative recordings of intramembrane charge movements elicited by 25-ms depolarizations from −80 to −40, −20, 0, and 20 mV shown for transfected FDB fibers expressing either V-Rem (A) or YFP (B). (C) The Q-V relationships for fibers expressing either V-Rem (n = 7; ○) or YFP (n = 5; ●) are shown. Charge movements were evoked at 0.1 Hz by test potentials ranging from −70 through 50 mV in 10-mV increments. The smooth curves for V-Rem– or YFP-expressing fibers are plotted according to Eq. 1, with the respective fit parameters shown in Table 1. Representative recordings of myoplasmic Ca²⁺ transients elicited by 25-ms depolarizations from −80 to −40, −20, 0, 20, and 40 mV are shown for FDB fibers overexpressing V-Rem (D) or YFP (E). (F) The peak ΔF/F-V relationships for V-Rem (n = 8; ○)– and YFP (n = 6; ●)-expressing fibers are shown. Ca²⁺ transients were evoked at 0.1 Hz by test potentials ranging from −70 through 60 mV in 10-mV increments. The smooth curves for V-Rem– and YFP-expressing fibers are plotted according to Eq. 3 with the respective fit parameters shown in Table 1. Error bars represent ±SEM.