Fig. 5. Segregation of PC from ERGIC-53 occurs at the level of exit from the ER. Cells expressing PC-FP were incubated, in the presence of cycloheximide, at 15°C for 60 minutes prior to addition of ascorbate and further incubation at 15°C for 90 minutes. Cell were then fixed with paraformaldehyde at 15°C and processed for immunofluorescence with anti-ERGIC-53. The majority of PC-FP containing structures (A; arrows) do not colocalise with ERGIC-53 (B; arrows). Similarly, the majority of PC-FP TCs (C; arrows) do not colocalise with COPI labelled TCs (D; arrows). Occasional examples of COPI-labelled PC-FP containing TCs are seen (C,D; arrowhead). For quantitation of results see Table 1. Bars=5 µm.