Fig. 2.

Recombinant DYRK2 stimulates ENaC currents in outside-out patches from Xenopus laevis oocytes. a, b, c, and d, Left panels, representative current traces recorded in outside-out patches of αβγENaC, α_S621AβγENaC, and α_P622FβγENaC expressing oocytes at a holding potential (V_hold) of − 70 mV. As indicated by the bars, bath solution was changed from a low Na⁺ (NMDG-Cl; [Na⁺] = 1 mM) to a normal Na⁺ containing solution (NaCl; [Na⁺] = 96 mM) without or with amiloride (Ami, 2 μM). Heat-inactivated DYRK2 (inactive DYRK2) or active recombinant DYRK2 (80 U/ml) were included in the pipette solutions as indicated under the traces. Right panels, summary of normalized ∆I_Ami values obtained from similar experiments as shown in the representative traces (left panels). Each grey line corresponds to an individual outside-out patch clamp recording and connects ∆I_Ami values obtained at different time points. The black lines in each graph connect average ∆I_Ami values (mean ± SEM; αβγENaC/inactive DYRK2, n = 8; αβγENaC/DYRK2, n = 13; αS_621AβγENaC/DYRK2, n = 7; α_P622FβγENaC/DYRK2, n = 6). ∆I_Ami values determined at individual time points were compared with the corresponding initial ∆I_Ami value at 4 min using paired Student’s ratio t-test. ** p < 0.01; *** p < 0.001