Figure 3.

Voltage and pH Regulation of AKT3-M260L and KST1-L262M.

K⁺ currents in 30 mM K⁺ of the channel mutants AKT3-M260L (upper traces) and KST1-L262M (lower traces) were recorded at membrane voltages in the range from +30 to −150 mV. From the holding voltage of −33 mV and −20 mV for AKT3-M260L and KST1-L262M, respectively, the membrane voltage was changed in steps of −20 mV. Upon a change in the extracellular pH from 5.6 to 7.4, K⁺ currents through AKT3-M260L increased (42.8 ± 1.2% at −130 mV), whereas those through KST1-L262M decreased (−27.6 ± 6.4% at −130 mV). For both channel mutants, representative current recordings out of three to four experiments are shown. The observed changes in steady state currents during the pH shift experiments were significantly different in the voltage range from −80 to −150 mV (P < 0.01).