FIGURE 3.
Effect of intracellular calcium chelator BAPTA-AM and CaM antagonist W7 on PDGF-BB-induced transient and sustained phosphorylation of Akt at Ser-473. ST88-14 cells were serum-starved for 4 h and then pretreated with vehicle, 25 μm BAPTA-AM (A), 10 μm W7 (B), or 10 μm W5 (B) for 30 min prior to PDGF-BB stimulation. Cells were harvested at 0 min (untreated), 30 min (to represent transient phosphorylation), and 120 min (to represent sustained phosphorylation), and total cellular protein was subjected to Western blot analysis. Blots were immunostained for pAktSer-473 and GAPDH (loading control), followed by peroxidase-conjugated secondary antibodies. Results are mean ± S.E. from three (A) or four (B) independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001.