Figure 8.

Akt and Erk activation dynamics. Akt (A) and Erk1 (B) activation patterns in parental cells (HER2-/3-), HER2 expressing cells (HER2+/3-), HER3 expressing cells (HER2-/3+), and HER2-HER3 co-expressing cells (HER2+/3+) during one hour time course following activation with low dosages of EGF (12 ng/ml), HRG (40 ng/ml), or both (EGF+HRG). Samples were collected at t = 0, 10, 30 and 60 min after ligand addition and receptor phosphorylation levels at these time points are presented as white, black, gray and cross line bars, respectively. Results are presented as the mean and SD of at least four measurements from two biological replicates. The data for each signaling protein was normalized with respect to the phosphorylation level in the HER2+/3+ cell line at t = 10 min when both ligands were added.