I_Cl,Ca densities in mock-, mTMEM16F-, and mTMEM16A-transfected HEK293 cells. (A) Typical current development recorded by a ramp protocol run every 15 s (left; see inset) and representative current-voltage relationships (right) of mTMEM16F (250 µM free [Ca²⁺]_i). Inward currents were initially inactivated similar to those in C; however, this inactivation is not visible at the given scale. (B and C) Mock (250 µM free [Ca²⁺]_i; B) and mTMEM16A (0.07 µM free [Ca²⁺]_i; C). “a” indicates where the step protocols were recorded. (D) Mean peak I_Ca,Cl current density when activated by 250 µM free [Ca²⁺]_i of mock and mTMEM16F, measured at 70 mV and −110 mV, respectively. Data are presented as mean ± SE of 14 mock- and 8 mTMEM16F-transfected cells and tested by one-way ANOVA: *, P < 0.05.