Figure 6
Analysis of electrophysiological properties of HEK293 cells in KCNQ2 homomeric and heteromeric P285T channels. (A) (a) Representative current traces of KCNQ2 WT (2 μg) (n = 20), P285T (2 μg) (n = 10), and KCNQ2 WT + P285T (1 μg:1 μg) (n = 10). (b) Current density versus membrane potential (from − 80 to + 40 mV) for KCNQ2 WT, P285T, and KCNQ2 WT + P285T. The current density in homomeric transfected P285T demonstrated the lowest conductance–current curve from − 30 to 40 mV. The conductance–current curves for KCNQ2 WT + P285T exhibited smaller increases in the currents than did homomeric P285T. *p < 0.05 for KCNQ2 WT versus P285T; + p < 0.05 for KCNQ2 WT versus KCNQ2 WT + P285T. (c) Normalized current (G/Gmax) versus voltage (from − 80 to 40 mV) for KCNQ2 WT, P285T, and KCNQ2 WT + P285T. The normalized currents were significantly lower in homomeric P285T (p < 0.05) during episodes of conditional stimulation from − 30 to − 20 mV. *p < 0.05 for KCNQ2 WT versus P285T. (B) (a) Representative current traces of KCNQ2 WT + KCNQ3 WT (1 μg + 1 μg) (n = 10) and KCNQ2 WT + P285T + KCNQ3 (0.5 μg + 0.5 μg + 1 μg) (n = 9). (b) Current density versus membrane potential (from − 80 to 40 mV) for KCNQ2 WT + KCNQ3 WT and KCNQ2 WT + P285T + KCNQ3. The conductance–current curve for KCNQ2 WT + P285T + KCNQ3 was lower than that for KCNQ2 WT + KCNQ3 WT cells. (c) Normalized current versus voltage for KCNQ2 WT + KCNQ3 WT and KCNQ2 WT + P285T + KCNQ3. After heteromeric KCNQ2 WT + P285T + KCNQ3 WT transfection into HEK293 cells, the currents remained low.
