Fig. 4. Subcellular localization of FAP-1 in Panc89 cells as revealed by confocal laser scanning microscopy. (A-C) Distribution of ß-COP (A) and FAP-1 (B) in untreated Panc89 cells. Arrows indicate a cisternal structure positive for both proteins (A-C). (D-F) Distribution of ß-COP (D) and FAP-1 (E) in Panc89 cells treated with 1 µg/ml brefeldin A for 60 minutes. Cells were labelled by indirect immunofluorescence staining using a polyclonal antibody against FAP-1 and detected by a secondary antibody labelled with red fluorescence. ß-COP was visualised with a monoclonal antibody and detected with a green labelled secondary antibody. Colocalization of both labels results in yellow colouring (C,F). FAP-1 and ß-COP clearly colocalize in untreated cells at juxtanuclear cisternal sites (C). Arrowheads depict individual vesicular staining for FAP-1 (C,F). After brefeldin A treatment, the Golgi cisternae were disrupted and ß-COP (D) and FAP-1 (E) were dispersed throughout the cell and totally separated (F).