Activity of PKD-kd and PKD-SE in cell culture. A) HEK293T cells were cotransfected with an expression plasmid encoding Flag-ss-HRP or empty vector, and PKD-kd, PKD-SE, or PKD-WT respectively. 24 h post-transfection, cells were washed and fresh medium was added. The supernatant was analyzed for peroxidase activity after 0, 1, 3 and 6 h by chemiluminescence. Values correspond to the mean of triplicate samples and error bars represent standard deviation. RLU, relative light units. B) COS7 cells were transiently transfected with expression plasmids encoding GFP-tagged PKD-kd, PKD-WT and PKD-SE. Cells were fixed 24 h post transfection and analyzed. The images shown are stacks of several confocal sections. Arrow points to TGN. Enlargement (boxed) of tubules (arrowhead) induced by PKD-kd overexpression is shown below the figure. Scale bar, 10 μm.