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Figure 1. Transferrin clearance from the endocytic recycling compartment (ERC) is delayed in Chinese hamster ovary (CHO) cells treated with the 
-secretase inhibitor DAPT. A) Transferrin (Tfn, red; b and g) colocalized with the endocytic recycling compartment marker Rab11 in the ERC (green in a and f) immediately after its uptake (0 h) in both control and DAPT-treated cells. Transferrin did not colocalize with Rab7 or Rab 9, late endosomal and lysosomal markers, in control (d and e) or in DAPT-treated cells (i and j). B) After 1-hour chase, transferrin completely cleared out from the ERC in control cells expressing Rab11 (a–c). In contrast, in DAPT-treated cells, transferrin still colocalized with Rab11 at the ERC (f–h; yellow in h), but not with Rab7 (i) or Rab9 (j). C) Quantitation of transferrin fluorescence in the ERC in CHO cells. Data shown are the average background-corrected fluorescence values in relative units ± SEM in control and DAPT-treated CHO cells immediately (0 h) and 1 h after transferrin labeling. **Statistically significant difference in comparison to control cells (Independent Samples Test, P
0.0001). All images are confocal. Scale Bars = 10 µm for a, b, f, g; 5 µm for c–e, h–j.
