FIGURE 4.

AMPK fails to inhibit CFTR in oocytes expressing catalytically inactive NDPK-A-H118F mutant. TEV recordings were performed 2 days after cRNA injection of CFTR and either wild-type NDPK-A (NDPK-A WT) or the catalytically inactive NDPK-A-H118F mutant into Xenopus oocytes. The oocytes were injected 2–4 h prior to recording with either potassium gluconate (Control) or the AMPK activator K-ZMP (ZMP). A and C, the mean (± S.E.) whole cell conductances are shown over time following addition of the cAMP agonists forskolin (1 μm) and IBMX (0.1 mm) at time 0 to activate CFTR in oocytes expressing either NDPK-A WT (A) or the NDPK-A-H118F mutant (C). B, ZMP injection inhibited the peak CFTR conductance in oocytes co-expressing CFTR and NDPK-A WT relative to control-injected oocytes. *, p < 0.001, ANOVA; data normalized to peak control-injected current. D, ZMP failed to inhibit CFTR conductance with co-expression of the catalytically inactive NDPK-A-H118F mutant (p > 0.10, ANOVA). Starting conductances were lower than peak conductances for all conditions. #, p < 0.001, ANOVA; n = 15–30 oocytes/condition from four to seven separate frogs for all conditions shown.