Figure 3. In vitro activity of CGS and caffeine on Akt phosphorylation. HLF and SK-Hep-1 cells were treated for 24 h with the indicated concentrations of CGS 15943 in the presence of serum. Akt activation was assessed by monitoring phosphorylation at its residues Ser473 (A and B) and Thr308 (C and D). Equal loading was assessed using an anti-ERK2 antibody. Alternatively membranes were stripped and re-incubated with an anti-Akt antibody. Phosphorylation of ERK1/2 was also assessed by using a specific antibody (E and F). Membranes were then stripped and re-incubated with an anti-ERK2 antibody.