FIGURE 8.

Intracellular trafficking of SubAB mutants. Vero cells were treated with 3 μg ml⁻¹ purified wild type SubAB or the indicated mutant derivatives for 30 min, and then fixed, permeabilized, and differentially stained for SubA (red) or SubB (green) using immunofluorescence, as described under “Experimental Procedures.” A, separate and overlaid confocal images are shown for SubA and SubB; in the overlay, nuclei are stained with DAPI (blue). B, SubB/SubA fluorescence intensity ratios were calculated either on whole fields or on the ER compartment. Data are the mean ± S.D. ratios for at least six fields/cells (*, p < 0.0001; **, p = 0.0001; unpaired Student's t test (relative to wild type ratio)).