Figure 4
From: Rab5 is critical for SNAP23 regulated granule-granule fusion during compound exocytosis
SNAP23 redistributes from the plasma membrane to the SGs in IgE/Ag-triggered cells. (a–c) RBL cells were co-transfected with 15 μg NPY-mRFP and 30 μg of either HA-wt-SNAP23, or HA-PD-SNAP23, or HA-PM-SNAP23, as indicated. Cells were either left untreated (UT) or sensitized with 1 μg/ml of IgE. Twenty-four hours after transfection, cells were either left untreated (UT) or triggered with 50 ng/ml of DNP-HSA (Ag) for 10 min. Cells were fixed and immunostained using monoclonal antibodies directed against HA followed by Hilyte Plus 488-conjugated goat anti-mouse IgG. Cells were analyzed by confocal microscopy. Bars = 5 μm. The insets are enlargements of the boxed areas. (d) Co-localization of SNAP23 (wt, PD or PM) with NPY-mRFP in non-triggered (UT, see also Fig. 3e) or IgE/Ag-triggered cells, was quantified by the Imaris software. The data are means ± SEM derived from four independent experiments. ***P (UT wt-SNAP23 vs. IgE/Ag wt-SNAP23) = 1.5 × 10−10, n = 40 cells for each condition (unpaired two-tailed Student’s t-test).
