Cells were lysed and subjected to western blot analysis as previously described [17 (link)]. Briefly, cells were lysed in sodium dodecyl sulfate (SDS) lysis buffer (2 % SDS, 10 % glycerol, 62 mM Tris-HCl, pH 6.8, and a complete mini-protease inhibitor cocktail [Roche Life Science]) and boiled for 10 min. After protein quantification, equal amount of protein was loaded, separated on a polyacrylamide gel, and transfering to a nitrocellulose membrane. Protein bands were immunodetected with appropriate antibodies, e.g., rabbit-anti- NEDD4L (Cell Signaling, Danvers, MA, Cat. No. 4013, 1:1000), mouse anti-E-cadherin (BD Transduction Laboratories, San Jose, CA, Cat. No. 610181, 1:1000), mouse antivimentin (Cell Signaling, Cat. No. 3390, 1:1000), rabbitanti-pSMAD2 (Cell Signaling, Cat. No. 9101, 1:1000), mouse anti-GAPDH (Santa Cruz Biotechnology, Dallas, TX, Cat. No. sc-47724, 1:4000), goat anti-actin (Santa Cruz Biotechnology, Cat. No. sc-1616, 1:1000), and their corresponding secondary antibodies (Santa Cruz Biotechnology).