FIG. 4.

EBV infection stimulates ERK and Akt activation through HER2/HER3 signaling pathway. (A) Western blot analysis of the activation of ERK and Akt downstream of HER2/HER3. Fifty micrograms of protein extracts was detected by 8% SDS-polyacrylamide gel electrophoresis and transferred onto nitrocellulose membranes for immunoblotting with antibodies specific to phospho-ERK1/2, ERK1/2, phospho-Akt, or Akt kinases. α-Tubulin was detected as an internal control. (B) Trastuzumab inhibits phosphorylation of ERK and Akt in MCF7-A cells. MCF7-A cells were treated with trastuzumab (10 μg/ml). At the indicated time points, the cells were washed and harvested in lysis buffer, and 50 μg of protein lysates was analyzed in immunoblotting with antibodies as indicated.