Fig. 3

Secretory capacity of proteins via different pathways in cultured human cell. Human 293T cells were transfected with either ER-Golgi-pathway reporter (SP-gLuc-GFP), exosome-pathway reporter (Exo-gLuc-GFP), or non-secretory cytosolic protein as control (dSP-gLuc-GFP) for 48 h. Both cells and conditioned medium from the above three groups were collected and subjected to luciferase activity assay. The total activity from both cytosol (cell lysate) and secretion (conditioned medium) were graphed (A and B) (n = 3, mean ± SD). The luciferase enzyme remaining inside of producing cells versus luciferase enzyme secreted into the conditioned medium was graphed to show the relative amounts of luciferase production in both compartments as compared to the controls (n = 3, mean ± SD) (C and D)