The limiting membranes but not the lumenal contents of LE/LYS can be fixed by FA. CV1 cells coexpressing CAV1-mCherry (red channel) and Lamp1-EGFP (green channel) were mounted in a live cell chamber. FA was added to final 4% at t = 0 s, and time-lapse imaging was performed on an epifluorescence microscope at 0.2 Hz. Note the disappearance of CAV1-mCherry from numerous endosomal structures within the initial minutes of fixation (red circles), leaving empty Lamp1-EGFP organelles behind. Video is displayed at 10× real time.
