The IQ/AA mutation disables function of Cav1.1 as a Ca2+ channel and voltage sensor for EC coupling. Representative whole-cell L-type Ca2+ currents recorded from dysgenic myotubes expressing either (a) YFP-Cav1.1 (cell 1 (05-10-02); linear capacitance pF) or (b) YFP-Cav1.1AA (cell 1 (01-13-03); linear capacitance pF). Note that the current scales are different in (a) and (b). (c) The average peak current density () is plotted as a function of membrane potential (). Data were obtained from the indicated number of myotubes for each group. The smooth lines through the data were generated by using equation (1) (see Methods) and the average values. (d) The average peak fluorescence () is plotted as a function of membrane potential (). Data were obtained from the indicated number of myotubes for each group. The smooth lines through data represent Boltzmann fits to the average data using equation (3) (see Methods).
