Fig. 1. AQP2 redistribution in response to FK in MCD4 cells. AQP2 trafficking was analyzed in polarized MCD4 cells grown on permeable support to full confluence. Cells were stained with antibodies against AQP2 and ZO-1 (both in green) and counterstained with WGA-TRITC (red) to visualize the plasma membrane. Confocal scans were taken in both the xy and yz plane. (A) In resting cells, AQP2 was mainly detectable in sub-apical vesicles. (B) After FK treatment, AQP2 localized to the apical membrane with a substantial co-localization with the plasma membrane marker. (C) MCD4 cells cultured on permeable support to full confluence display a positive staining for the tight junction marker ZO-1, indicating a full polarization.