Western blot analysis of SI in Lane 1: human HeLa whole cell lysate, Lane 2: human COLO-320 whole cell lysate, Lane 3: human SHG-44 whole cell lysate, Lane 4: human HEK293 whole cell lysate. Electrophoresis was performed with 5-20% SDS-PAGE gel (70V, Stacking gel; 90V Resolving gel, Time: 2-3 hours), transferred to a nitrocellulose membrane and blocked using 5% Non-fat Milk/TBS (1.5 hrs at room temperature). Samples were incubated with SI polyclonal antibody (Product # PA5-95609) using a 0.5 µg/mL dilution, followed by a goat anti-rabbit IgG-HRP at a dilution of 1:10,000, and developed with enhanced chemiluminescence (ECL).