FIGURE 3.

Properties of TMEM16A-dependent currents in HEK-293 cells. A, whole cell membrane currents in HEK-293 cells transiently transfected with the indicated isoforms and mutants. Membrane currents were elicited by stepping membrane potential from −100 to 100 mV in 20-mV increments from a holding potential of −60 mV. Dotted lines indicate the zero-current level. The intracellular free Ca²⁺ concentration was 305 nm. B, current-voltage relationships determined for the various isoforms and mutants. Current amplitudes were measured at the end of test pulses. pF, picofarads. C, rectification index determined as the ratio of the current measured at +100 mV to the current measured at −100 mV. *, p < 0.05; **, p < 0.01 versus (abc) isoform. D, normalized instantaneous current (i.e. the ratio of the current at the beginning to that at the end of the voltage pulse). **, p < 0.01 versus (abc) isoform. Data in B–D are mean ± S.E. (n = 12–26).