Figure 2. Phosphorylation of FoxO family members in response to serum and stretch in hGF. (A) hGF were cultured in serum-free medium for 24 hrs prior to stimulation. Cells were then stimulated with 10% FBS for the times indicated (in min). A 20-µg quantity of total cellular proteins was separated by SDS-PAGE, transferred to nitrocellulose, and probed with phospho-specific FoxO1/FoxO4 antibody (upper panels) or actin (lower panel). The upper panels represent different film exposure times. (B) hGF were cultured in serum-free medium for 24 hrs prior to stimulation. Cells were then subjected to stretch for the times indicated (in min). A 20-µg quantity of total cellular proteins was separated by SDS-PAGE, transferred to nitrocellulose, and probed with phospho-specific FoxO1/FoxO4 antibody (upper panel) or total FoxO1/FoxO4 antibody (lower panel). (C) Densitometric analysis of phosphorylated FoxO1 normalized to FoxO1 for two independent stretch experiments (represented as fold induction over static controls) (N = 2; 1 min – 1.49 ± 0.09; 5 min – 1.82 ± 0.014; 10 min – 2.37 ± 0.05; 30 min – 3.65 ± 0.28; 60 min – 4.50 ± 0.41).