Figure 17.

Cultured rat VMs overexpressing SK2 phosphomimetic mutant S465A show no SK current

A, representative traces of [Ca²⁺]_i transients and I _SK at baseline and after incubation with ISO (100 nmol L^–1, 3 min) in VMs expressing the rSK2‐S465A mutant or WT rSK2 (from Fig. 10) B, pooled mean ± SD I–V and peak [Ca²⁺]/V relationships for (A), n = 5–6, N = 5 and rSK2 WT + ISO data from Fig. 6. I _SK: ^* P = 0.02 (−35 mV), P = 0.005 (−25 mV), P = 2.2 × 10⁻⁴ (−15 mV), P = 4 × 10⁻⁴ (−5 mV), P = 6.6 × 10⁻⁴ (5 mV), P = 1.8 × 10⁻⁴ (15 mV), P = 5.7 × 10⁻⁴ (25 mV), P = 0.001 (35 mV), P = 0.001 (45 mV), P = 0.001 (55 mV) WT ISO vs. S465A baseline. ^** P = 0.01 (−25 mV), P = 4.8 × 10⁻⁴ (−15 mV), P = 7.6 × 10⁻⁴ (−5 mV), P = 0.001 (5 mV), P = 3.9 × 10⁻⁴ (15 mV), P = 0.001 (25 mV), P = 0.002 (35 mV), P = 0.003 (45 mV), P = 0.004 (55 mV) rSK2 WT ISO vs. rSK2‐S465A ISO. [Ca²⁺]: ^* P = 0.02 (35 mV), P = 0.03 (45 mV), P = 0.002 (55 mV) WT ISO vs. S465A baseline, one‐way ANOVA with a Bonferroni post hoc test. C, representative western blots from VMs expressing rSK2 WT, rSK2‐S465D and rSK2‐S465A.