Corresponds to Fig. 1 b. Two cells imaged by epi-illuminated wide-field (EPI) and total internal reflection (TIR) or evanescent wave microscopy. Organelles and TCs away from the plasma membrane (>100 nm) are visible by EPI (red) only. Once TCs approach the plasma membrane, they also become visible by TIR (green). Note that initially red TCs turn yellow and then green when about to dock and fuse with the plasma membrane. A transport container (TC), moving away from the Golgi and then undergoing partial fusion with the plasma membrane, is marked by an arrow and shown enlarged in Videos 3 and 4. Two successive fusion events in close proximity are circled and enlarged in Videos 5 and 6. The whole sequence is 300 frames (300 s). Frame width, 85 µm. All movies are played at 15 fps, which corresponds to 15 times real speed. For optimal viewing of fusion events, movies should be played both forwards and backwards.
