Standard protocol was followed for immunofluorescence experiments. The antibodies used were goat anti-AQP4 (C-19) polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, CA), at a dilution of 1:50; goat anti-AQP5 (C-19) polyclonal antibody (Santa Cruz), dilution 1:400; goat anti-NKCC1 (N-16) polyclonal antibody (Santa Cruz), dilution 1:50; mouse anti-NKA β1 (C464.8) monoclonal antibody (Santa Cruz), dilution 1:100; mouse anti-NHE1 (C terminus, clone 4E9) monoclonal antibody (Millipore, Temecula, CA), dilution 1:100; mouse anti-CFTR (C terminus) monoclonal antibody (R&D Systems, Minneapolis, MN), dilution 1:250; and mouse anti-ClC2γ monoclonal antibody (Abcam, Cambridge, MA), dilution 1:100. The secondary antibodies used were fluorescein isothiocyanate (FITC)– or rhodamine red–conjugated donkey IgG, dilution 1:400 (Jackson ImmunoResearch, West Grove, PA). Rhodamine-conjugated phalloidin (Invitrogen, Carlsbad, CA), at a dilution of 1:200, was also used on some slides to stain F-actin. Slides were examined with a laser scanning confocal microscope (LSM510; Carl Zeiss Meditec, Dublin, CA) and the images analyzed with image-editing software (PhotoShop; Adobe Systems, Mountain View, CA).