Forced expression of wild-type or catalytically inactive Smurf2 stabilizes NEDD9 protein. (A) HeLa cells were co-transfected with Myc-NEDD9 and either empty vector (pcDNA) or FLAG-Smurf2 (Sm2). Similar conditions were used to co-transfect with GFP-NEDD9 and either empty vector (mCherry) or mCherry-Smurf2. After 48 h, cells were harvested for immunoblotting. (B) HeLa cells were co-transfected with the indicated plasmid as described in (A). Co-transfection of wild-type (WT) or catalytically inactive (C716A) Smurf2 increased NEDD9 expression.