I-V relations of TMEM16B. (A) Representative whole cell voltage-clamp recordings obtained with an intracellular solution containing nominally 0 Ca²⁺ or 1.5 µM Ca²⁺, as indicated. Voltage steps of 200-ms duration were given from a holding voltage of 0 mV to voltages between −100 and +100 mV in 20-mV steps, followed by a step to −100 mV, as indicated in the top part of the panel. (B) Steady-state I-V relation measured at the end of the voltage steps (circles) or instantaneous I-V measured at the beginning of each voltage step (inverted triangles) from the cell shown in B. (C) Representative recordings at 1.5 µM Ca²⁺ obtained with a voltage protocol consisting of a prepulse to +100 mV from a holding voltage of 0 mV, followed by voltage steps between −100 and +100 mV in 20-mV steps, as shown in the top part of the panel. (D) I-V relations measured from tail currents (inverted triangles) or at the steady state (circles).