Fig. 4. Tie2 protein levels decrease in Ang1 and Ang2 stimulated HUVECs. (A) HUVECs were stimulated with pre-clustered Ang1 (800 ng/ml) or Ang2 (800 ng/ml) for the indicated times. Total cell lysates were analyzed by western immunoblotting using a monoclonal Tie2 antibody to detect total receptor levels and an anti-ß-actin antibody to verify that equal amounts of protein were analyzed. Time 0 represents cells stimulated with medium alone. (B) The intensities of the bands in A were quantified and expressed as a percentage of the t=0 value and plotted against time, Ang1 () Ang2 (). Results are mean ± s.e.m. of three independent experiments.