Fig. 6. Transport of CB-EGFP in living FRT cells. Single channel fluorescence (A,B,D'',D'''), merged (C,D) and phase contrast micrographs (D') of FRT cells transiently expressing CB-EGFP taken in the conventional (A) or the confocal mode (B-D''') at 37°C (A,C), 20°C (B) or after fixation and immunolabeling with antibodies against rat lgp96 (D). During steady state, CB-EGFP was detectable within the lumen of the ER, the Golgi apparatus and within vesicles (A). Note, the accumulation of CB-EGFP within the TGN after incubation of the cells at 20°C (B), its subsequent transport to vesicles after shifting to the transport-permissive temperature of 37°C (C) and its colocalization with the lysosomal marker lgp96 (D). Micrographs of different focal planes are merged in C, and colored in blue, green and red as indicated. Yellow signals in D are indicative of colocalization of green fluorescent CB-EGFP (D''') with lgp96 (D''). Arrowheads point to ER-cisternae, stars mark the positions of the Golgi and the TGN and arrows indicate lysosomes. N, nuclei. Bars, 50 µm (A,C), 20 µm (B,D,D').