MTSET modification of I521C is voltage dependent. (A) Currents measured from I521C over time during perfusion with 1 mM MTSET. Cell was held at −80 mV and pulsed to +40 mV for 500 ms every 10 s. Tail currents at −110 mV were measured at the point indicated by the symbol on the current trace, in control (gray) and during exposure to MTSET (black). Note increase in sustained inward currents at −110 mV and slowed tail decay in MTSET. (B) Cells were held at the indicated holding potential (hp) in each panel. They were exposed to MTSET for 10 min, which was then washed off. Cells were held at −80 mV and pulsed to +40 mV for 2 s, followed by a 2-s hyperpolarization to −110 mV to record currents before (gray) and after MTSET (black).