FIG. 6.
Effect of PI3K inhibition on fusion of FV. (A) Serum-starved HepG2 cells were pretreated with wortmannin (100 nM) and cytoB (10 μM), followed by 1 h of incubation with 80 μg FV (RITC-L loaded). Images were captured with a confocal microscope. Virosome-cell fusion was assessed by RITC-L delivery into the cytosol. (B) Corresponding cell lysates were subjected to SDS-10% PAGE, followed by Western blotting using anti-phospho-AKT antibody (upper panel). The same blot was stripped and reprobed with anti-AKT antibody (lower panel). (C) HepG2 cells were also assayed for PI3K activity after similar treatments. Cells were lysed and equal amounts of protein (lower panel) were used for immunoprecipitation with mouse monoclonal anti-phosphotyrosine antibodies, and the immunocomplexes were assayed for the ability to phosphorylate PI to PIP as described in the text. Bar, 23.81 μm.