Fig 9. Deactivation time constants for hERG and its mutants.

A) Representative traces from the indicated hERG constucts at -100 and -120 mV repolarization voltages. Tail currents (from the dash-boxed region of the voltage protocol) were fitted with a standard biexponential equation (red dashed line) to measure deactivation time constants (see methods). B) Average τ_fast for S624A, Y652A and T623A constructs at -120 mV were all significantly smaller than their respective WT controls (p = 0.0082, p = 0.0134, and p < 0.0001 respectively). At -100 mV, Y652A and T623A were significantly different from their respective WT controls (p = 0.0054 and p = 0.0009), while S624A was not (p = 0.0953). F656A was not different from WT_{High K+} (p = 0.4973 at -120 mV and p = 0.9430 at -100 mV). N = 6–10; one-way ANOVAs. C) τ_fast before (Control) and during R-roscovitine application at -120 mV. R-roscovitine sped up deactivation for WT (p = 0.0034) and T623A (p = 0.0009), but not for S624A (p = 0.312), Y652A (p = 0.2739), or F656A (p = 0.1708). N = 6–10; paired t-tests. R-roscovitine concentration was 200 μM for low K⁺ and 500 μM for high K⁺ solutions. * = P < 0.05, ** = P < 0.01, and *** = P < 0.001.