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Fig. 5. Trafficking of CB-EGFP in FRTL-5 cells. Single channel fluorescence (lower
panels, middle and right, and inset in D), merged (A-D) and phase contrast
micrographs (lower panels, left) of FRTL-5 cells transiently expressing
CB-EGFP were taken with a confocal LSM after immunolabeling with antibodies
against the ER-resident protein PDI (A, red), the Golgi mannosidase II (B,
red), the endogenous lysosomal cysteine protease cathepsin B (D, red) and
after pulse-chase loading of lysosomes with Lyso Tracker (C, red). For
reference, the inset in D shows non-transfected FRTL-5 cells after
immunolabeling of cathepsin B. Yellow signals are indicative of
colocalization. Arrowheads point to ER-cisternae; stars mark the positions of
the Golgi and arrows indicate lysosomes. N, nuclei. Bars, 40 µm.