Whole cell protein was collected using Pierce RIPA lysis buffer (Thermo Scientific) with 1x Roche cOmplete protease inhibitor. Western blotting was performed, as described37. Five μg of total protein was run per well in NuPAGE Novex 4–12% Bis-Tris Midi Protein Gels (Life Technologies). The mouse purified anti-SMN antibody (BD Biosciences) and the rabbit anti-Cofilin antibody (D3F9, Cell Signaling) were used as primary antibodies (Both were diluted to 1: 10,000, incubated for 1 hour at room temperature). HRP-conjugated goat anti-mouse IgG (H + L) (Bio-Rad) and HRP-conjugated goat anti-rabbit IgG (H + L) (Bio-Rad) were used as secondary antibodies (Both were diluted to 1:10,000). The bands were detected using Amersham ECL Select Western blotting detection kit (GE Healthcare).