Figure 5.

Cellular Localization of Bestrophin-1 Isoforms in MDCK II and HEK293 Cells

Transiently transfected MDCK II cells (A–D and F) were polarized on Transwell membranes before immunofluorescent labeling with bestrophin-1 antibody (green in A–D and F) and confocal microscopy. Nuclei were labeled with DAPI (blue). A representative lateral (Z-stack) image is shown. WT (A) and p.I205T (B) isoforms localized to the basolateral membrane. A vertical optical section shows that WT bestrophin-1 (green) localizes basal to the tight junction maker ZO-1 (red) (insert, A). The p.L140V (C) and p.D228N (D) isoforms exhibited a diffuse cytoplasmic localization. The p.D312N mutant isoform has a cytoplasmic localization (E). WT bestrophin-1 (red) expressed in HEK-293 cells does not traffic to the cell membrane (F).