Fig. 4. Visualization of Syt IX localization. RBL-Syt IX⁺ (A), control RBL (B,C) or RBL cells stably transfected with Syt IX-GFP cDNA (D-F) were labeled with anti-C2A-Syt IX (10 µg/ml) (A,D-F) or anti-N-Syt IX (10 µg/ml) alone (B), or together with mouse anti-serotonin (C) followed by rhodamine-conjugated donkey anti-rabbit and FITC-conjugated donkey anti-mouse IgG. Cells were processed for immunofluorescent staining and visualized by confocal microscopy, as described under Materials and Methods. Bars, 5 µm (A,B,D-F); 3 µm (C).