Fig. 2. GFP-FR and GFP-PrP are differently sorted in MDCK cells. MDCK cells stably expressing GFP-FR or GFP-PrP were grown on filter for 4 days. (A,B) Cells were analysed in vivo in (A) CO2-independent medium or (B) stained with an anti-GFP antibody followed by a TRITC-conjugated secondary antibody under non-permeabilising conditions. Serial confocal sections were collected from top to bottom of cell monolayers. (C) Cells were labelled with LC-biotin, which was added to their apical (Ap) or basolateral (Bl) surface. After immunoprecipitation using anti-GFP antibody, samples were separated by SDS-PAGE and biotinylated proteins were revealed using HRP-streptavidin. Bars, 10 µm.