Expression of Rho-GDI, Cofilin, PDGF receptor α, and MAPKBP-1 decreases upon IGF-1 stimulation of C2C12 cells. A) Triplicate samples from three different C2C12 cell preparations were stimulated with IGF-1 (100 ng/ml) for up to 8 hours, fractionated using batch ion-exchange, separated by 2D electrophoresis, and proteins were detected with silver stain. The protein highlighted by a yellow square (Rho-GDI, Cofilin, PDGF receptor α, and MAPKBP-1) decrease in expression after IGF-1 treatment. PDQuest analysis indicates a quantitative change in the protein based on total quantitation of the entire gel. B) Western blot analysis confirms the sustained decrease in protein expression for Rho-GDI, cofilin, and the PDGF receptor.