Western blot was performed using SMAD2 Monoclonal Antibody (R.542.9) (Product # MA5-14996) and a ~55 kDa band corresponding to SMAD2 was observed across cell lines tested. Whole cell extracts (30 µg lysate) of HepG2 (Lane 1), A549 (Lane 2), MCF7 (Lane 3), HEK-293 MSR (Lane 4) and HeLa (Lane 5) were electrophoresed using NuPAGE™ 4-12% Bis-Tris Protein Gel (Product # NP0321BOX), 10 well. Resolved proteins were then transferred onto a nitrocellulose membrane (Product # IB23001) by iBlot® 2 Dry Blotting System (Product # IB21001). The blot was probed with the primary antibody (1:1000 dilution) and detected by chemiluminescence with Goat anti-Rabbit IgG (H+L) Superclonal™ Recombinant Secondary Antibody, HRP (Product # A27036, 1:10,000 dilution) using the iBright™ FL1500 Imaging System (Product # A44115). Chemiluminescent detection was performed using SuperSignal™ West Pico PLUS Chemiluminescent Substrate (Product # 34580).