Voltage-clamp recordings in Xenopus oocytes. Oocytes were injected with either Nedd4–2 cRNA (500 pg, N = 14), cystic fibrosis transmembrane conductance regulator (CFTR) cRNA (50 pg, N = 66), or CFTR cRNA plus Nedd4–2 cRNA (50 and 500 pg, respectively, N = 77). A: current-voltage (I/V) plots of IBMX-stimulated currents. B: summary of IBMX-stimulated currents at −80 mV. ***P < 0.001.