Fig. 4.
Recombinant GSK3β inhibits ENaC currents. Left panels, representative current traces recorded in outside-out patches of αβγENaC (a, b, c), αS617AβγENaC (d), or αS621AβγENaC (e) expressing oocytes as described in Fig. 2. Heat-inactivated GSK3β (inactive GSK3β) or active recombinant GSK3β (16 U/ml) were included in the pipette solutions as indicated under the traces. In c, the GSK3β inhibitor CHIR99021 (2 µM) was included in the pipette solutions together with GSK3β. Right panels, summary of normalized ∆IAmi values obtained from similar experiments as shown in the representative traces (left panels) using the same symbols as in Fig. 2. αβγENaC/inactive GSK3β, n = 9; αβγENaC/GSK3β, n = 20; αβγENaC/GSK3β + CHIR99021, n = 8; αS617AβγENaC/GSK3β, n = 7; αS621AβγENaC/GSK3β, n = 6. ∆IAmi values determined at individual time points were compared with the corresponding initial ∆IAmi value at 4 min using paired Student’s ratio t-test. *** p < 0.001