Fig. 6

PBM mutation diminishes depolarization-induced SR Ca²⁺ release and DHPR Ca²⁺ currents in dyspedic myotubes. Dyspedic myotubes were transfected with either WT RyR1 or RyR1 K-Q mutant. a, b Representative L-type currents (lower trace) and Ca²⁺ transient (upper trace) obtained following depolarization to the indicated potentials of dyspedic myotubes expressing either a WT RyR1 or b RyR1 K-Q mutant. c Voltage dependence of average (±SEM) peak L-type Ca²⁺ current density (pA/pF) as a function of voltage. The data were fit (continuous line) with a modified Boltzmann function. d Voltage dependence of average (±SEM) peak Ca²⁺ transient amplitude as a function of voltage. The data were fit (continuous line) with a Boltzmann function. c, d Average (±SEM) values of the parameters from individual fits to each myotube are shown in Table 1. e The average (±SEM) peak of the first derivative of the fluo-4-fluorescence trace elicited during the test depolarization at 30 mV. c–e n = 10–12 myotubes