Fig. 4.
Akt mediates p70S6K phosphorylation and marker protein expression in SMCs on polymerized collagen. SMCs were cultured on polymerized collagen for 48 h (CL), and then costimulated with PDGF-BB and IL-1β (PDGF+IL) (A) or kept without being stimulated by these agonists (B) for 24 or 48 h. Before culturing on polymerized collagen, the cells were infected with adenoviruses encoding control green fluorescence protein (Ad-GFP), or hemagglutinin (HA)-tagged dominant-negative (Ad-DN-Akt) or dominant-positive Akt (Ad-Myr-Akt), as described in Materials and Methods. The cells were lysed, and their p70S6K phosphorylation and SMα-actin, SM-MHC, and calponin protein expressions were determined by using Western blot analysis. Infection was confirmed by the increases in Akt and HA expression in the Ad-DN-Akt- and Ad-Myr-Akt-infected cells. Results are representative of triplicate experiments with similar results.