(a)
(b)
Figure 3: Replicative senescence-dependent increase in intracellular PIP3 levels through PTEN downregulation. (a) Expression levels of PI3K and PTEN, in various PDs of HDFs. Various PDs of HDFs were analyzed by western blotting for PTEN, PI3K p85 subunit, and β-actin. (b) PIP3 immunofluorescence staining in various PDs of HDFs. Various PDs of HDFs were fixed with 4% paraformaldehyde, incubated with anti-PIP3 antibody and stained with TRITC-labeled anti-mouse IgM antibody. Images were acquired using an Olympus FluoView™ laser scanning confocal microscope.