Protein Extraction and Immunoprecipitation Protocol

Cells were lysed with RIPA buffer containing protease and phosphatase inhibitor cocktails (Roche, Basel, Switzerland), as previously described [16 (link)]. Equal amounts of protein were separated by SDS–PAGE and transferred to membranes. For immunoprecipitation, cell lysates were incubated with antibodies and Protein A/G Magnetic Beads (HY-K0202, MedChem Express), followed by western blotting. Western blotting was performed as previously described [19 (link)] with specific primary antibodies and horseradish peroxidase-conjugated secondary antibodies, followed by visualization using chemiluminescence (DNR Bio-Imaging Systems, Jerusalem, Israel). The antibodies used were as follows: anti-cyclin G2 (DF2284, Affinity Biosciences), anti-Flag (M20008XS, Abmart), anti-PP2Ac (2038 T, Cell Signaling Technology), anti-STAT1 (14994S, Cell Signaling Technology), anti-p-STAT1 (Y701) (9167S, Cell Signaling Technology), anti-lamin B1 (sc-6216, Santa Cruz), anti-β-tubulin (M30109XS, Abmart), anti-GAPDH (M20006F, Abmart), and anti-IgG (3900S, Cell Signaling Technology).