Figure 3: MCD4 cells express a central cilium and show polarized trafficking of AQP2. Confocal images of MCD4 cells under resting condition or stimulated with FK (see Methods for details). Sections were taken at the apical pole in the xy plan or in the xz plan. Acetylated tubulin (red) coincides with the central cilia, at the cell top. AQP2 (green) shuttled from a storage intracellular compartment to the apical membrane, upon FK stimulation. Overlay images show that AQP2 and acetylated tubulin may colocalize after FK stimulation.