HUVECs infected with Ad.LacZ (control) or Ad.PTP1B-WT (A) or transfected with scrambled or PTP1B siRNAs (B) were stimulated with VEGF (20 ng/mL) for 5 min. Lysates were immunoblotted with phospho-ERK1/2, ERK1/2, phospho-p38MAPK, p38MAPK, PTP1B or actin antibody. Representative blots for ERK1/2 and actin are reprobe from p-ERK1/2 membrane. The representative p-p38MAPK blot is derived from different lysates used for p-ERK1/2 blot, and is reprobed for p38MAPK blot. Bottom panels show averaged data obtained from more than 3 independent experiments, expressed as fold change of phosphorylation over basal (means ± S.E., n=3). *P < 0.05 vs. Ad.LacZ (A) or Scrambled siRNA (B) at each time point.