Fig. 3.

c-Src mediates serum starvation-induced E-cadherin expression. A: A549 cells were transfected with V5 tagged dominant negative c-Src plasmid (Dn-c-Src-V5) for 48 h, and media was then replaced with serum-free medium for 24 h. E-cadherin and β-actin levels were analyzed by immunoblotting. B: A549 cells transfected with increasing Dn-c-Src-V5 plasmid (0, 0.5, 1, 2 μg) for 48 h were then cultured in serum-free medium for 24 h followed by immunoblotting. C: A549 cells were cultured in serum-free conditions for 0–24 h. Immunoprecipitation of tyrosine phosphorylated proteins with an antibody to phosphotyrosine (p-Tyr), followed by E-cadherin and p-Tyr immunoblotting. Whole cell lysates (WCL) were analyzed with E-cadherin and p-Tyr immunoblotting. D: coimmunoprecipitation of c-Src with E-cadherin was performed after starvation (24 h) by c-Src antibody immunoprecipitation of c-Src binding complex followed by E-cadherin immunoblotting. Shown are representative blots from 3 independent experiments except C (2 experiments).