Synaptotagmin VII Restricts Fusion Pore Expansion during Lysosomal Exocytosis (original) (raw)
Figure 3
Presence of Syt VII Restricts the Size of the Fusion Pore
The lumen of lysosomes was loaded simultaneously using different-sized FITC- and TRITC-labeled dextran, using the approach described in Figures 1 and 2. Representative plots shown here demonstrate the fate of both dextran populations in individual lysosomes following the increase in intracellular calcium by addition of calcium ionophore. In WT MEFs, exocytosing lysosomes that released 70 kDa TRITC–dextran also simultaneously released 70 kDa FITC–dextran (A and B), 250 kDa FITC–dextran (C and D), but not 500 kDa FITC–dextran (E and F). In Syt VII KO MEFs, lysosomes that released 70 kDa TRITC–dextran also released 500 kDa FITC–dextran (G and H). In all cases the plots represent the normalized fluorescence intensity of the region marked in the images by dotted circles.