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. 2009 Apr 22;284(24):16562–16574. doi: 10.1074/jbc.M109.010918

FIGURE 9.

FIGURE 9.

S449A mutation prevents modulation of Kv1.2 current amplitude by PKA activation or inhibition. A, representative families of whole-cell currents recorded during 200-ms pulses between −80 and +30 mV in 10-mV steps from HEK 293 cells transiently expressing Kv1.2-WT (WT; n = 4) or Kv1.2-S449A (S449A; n = 4) before (Control) and after 8-Br-cAMP (1 mm; 8-Br-cAMP) treatment and the corresponding mean (±S.E.) fractional I-V relations in control (open circles) and 8-Br-cAMP (closed circles) (i.e. plots are the average values of end pulse current at each voltage ± 8-Br-cAMP normalized to value in control condition at +30 mV in each cell). Mean fractional current in 8-Br-cAMP was significantly greater than that in control condition at all voltages positive to −40 mV for Kv1.2-WT (p < 0.05; unpaired Student's t test) but not different for Kv1.2-S449A. B, representative families of Kv1.2-WT (WT; n = 4) or Kv1.2-S449A (S449A; n = 3) whole-cell currents and corresponding mean ± S.E. fractional I-V relations (as in A) before (Control) and after Rp-CPT-cAMPS (25 μm; Rp-CPT-cAMPS) treatment. Mean fractional current in Rp-CPT-cAMPS was significantly reduced compared with control conditions at all voltages positive to −20 mV for Kv1.2-WT (p < 0.05; unpaired Student's t test) but not different for Kv1.2-S449A.