Acidic mMVBLs fuse to nonacidic SVs in SCs. SC from a 2-d-old male expressing CD63-GFP (green) and stained with LysoTracker red was imaged using time-lapse confocal microscopy using a laser-scanning confocal microscope (LSM 510; Carl Zeiss). Frames were taken every 13.6 s. Stills from this video are shown in Fig. 4 A. Video was produced over a 5-min period. Note how CD63-GFP appears to be transferred to the limiting membrane of the mMVBL at the moment of fusion.
