FIGURE 4.

Deletion of a knuckle domain does not change the degradation rates of individual ENaC subunits. Cycloheximide chase experiments were performed as described under “Experimental Procedures” in WT yeast strains expressing a mouse ENaC subunit with a C-terminal HA epitope tag. A, α (open circles) or αΔK (closed circles); B, β (open circles) or βΔK (closed circles); C, γ (open circles) or γΔK (closed circles). Representative blots are shown below each graph. Chase reactions were performed at 37 °C, and lysates were immunoblotted with anti-HA antisera (ENaC) and with anti-glucose-6-phosphate dehydrogenase (G6P) as a loading control. Data represent the means of 3–7 experiments ± S.E. (error bars). No significant difference at each time point between the WT and mutant subunits was found (all p > 0.05, from two-way analysis of variance).