FIGURE 8.
The PDZ domain in CNK3 is essential for its ability to stimulate ENaC activity. In contrast to full-length-CNK3, ΔPDZ-CNK3 cannot restore aldosterone-induced ENaC activity in mpkCCDc14 cells stably silencing the expression of endogenous CNK3. mpkCCDc14 cells stably silencing the expression of endogenous CNK3 (shRNA4) were transiently transfected with shRNA-resistant full-length (“res-CNK3”) or ΔPDZ-CNK3 (“res-ΔPDZ-CNK3”) constructs using nucleofection. Parental mpkCCDc14 cells nucleofected with an empty vector (VC) were used as a positive control (control). Unmodified wild-type CNK3 expression construct was used as an additional control (“WT-CNK3”). Shown are a graphical representation of the Ieq measured 3 h after aldosterone stimulation (1 μm) and a representative Western blot demonstrating the rescue of the exogenously expressed shRNA-resistant WT- and ΔPDZ-CNK3-V5 constructs. *, p < 0.05; ***, p < 0.001 (n = 6). Error bars represent S.E. IB, immunoblot; WCL, whole-cell lysate.