Fig. 3.

WNK4 and the WNK4 Q562E mutant reduce large-conductance, Ca²⁺-activated K⁺ (BK) channel α-subunit cell surface and whole cell expression. A: HEK293 cells were transfected with GFP alone (control), myc-tagged BK α-subunit, or myc-tagged BK α-subunit with either wild-type (WT) or mutant (Q562E) WNK4. Following surface biotinylation, surface proteins were recovered with streptavidin-conjugated beads and then subjected to immunoblotting (IB) with an anti-myc antibody to detect BK α-subunits or with an anti-actin antibody as a control. In addition, whole cell lysates were subjected to IB with an anti-myc antibody to detect BK α-subunit or with an anti-actin antibody. Results are representative of three experiments. B: summary of analyses of BK α-subunit cell surface and whole cell expression. Immunoblots were quantified as described in materials and methods. Relative BK α-subunit cell surface and whole cell expression are shown, normalized to whole cell actin levels (n = 3, **P < 0.01, ANOVA followed by Tukey's multiple comparison test).