Different rate of transport of FP-22 and VSVG to the plasma membrane. CV1 cells, microinjected with the cDNA coding for Cerulean-22 and VSVG-YFP, were incubated for 75 min at 30°C and then at the same temperature in the presence of 50 μg/ml cycloheximide for the indicated times. Each row shows the same field visualized for the indicated protein as well as the merged image with the indicated pseudocolors. Even at the early time points, most of the viral protein is in the Golgi complex, whereas FP-22 is mainly in the ER. 45 min after cycloheximide addition, both the proteins are found in the Golgi and at the plasma membrane, although FP-22 is still present in the ER. At 75 min, although YFP-VSVG is almost totally localized at the plasma membrane, FP-22 is still found in the Golgi (arrows) and in the ER. Note that the nuclear envelope is visible in the cerulean (FP-22) but not the YFP channel (arrowheads). Bars, 20 μm.