Fig. 2.

Colocalization of AQP2 and caveolin-1. Confluent MDCK-hAQP2 cells grown on permeable supports without any treatment as a control (a–c), treated with forskolin for 30 min (d–f), or treated with forskolin for 30 min, washed, and then incubated without forskolin for 30 min (g–i) were fixed. Cells were sectioned perpendicular to the supports with a cryostat and double-immunofluorescently labeled for AQP2 (red) and caveolin-1 (green). Nuclei were stained with DAPI (blue). Merged confocal images are shown on the left. In the control, AQP2 is seen in the subapical cytoplasm and seems not to colocalize with caveolin-1, which is present on the apical membrane. AQP2 is largely colocalized with caveolin-1 on the apical membrane upon forskolin treatment. Some AQP2 internalized after washout is colocalized with caveolin-1. Bar=10 µm.