Fig. 4.

Aldosterone Rapidly Promotes Redistribution of ENaC Subunits

M1-CCD cells were transfected with plasmids expressing ENaCα, ENaCβ, or ENaCγ as eCFP fusion proteins (green). The subcellular distribution of each of the ENaC subunits was examined by confocal microscopy in untreated cell monolayers and cells treated with aldosterone (10 nm) for 2 min. Cells were counterstained with TRITC-labeled phalloidin to detect polymerized actin (red), and single (XY) focal plane images through the center of the cells are shown. Small dense accumulations of each of the ENaC subunits were observed within 2 min of aldosterone treatment (white arrows). M1-CCD cells were transfected with a plasmid expressing ENaCα as an eCFP fusion protein (green). The subcellular distribution of ENaCα was examined by confocal microscopy in cell monolayers pretreated with spironolactone (20 μm) or rottlerin (20 μm) for 30 min in advance of aldosterone (10 nm) treatment for 2 min. Cells were counterstained with TRITC-labeled phalloidin to detect polymerized actin (red), and single (XY) focal plane images through the center of the cells are shown. Small dense accumulations of ENaCα were observed within 2 min of aldosterone treatment (white arrows), which were absent in cells pretreated with spironolactone or rottlerin.