Western Blot Analysis of Cellular Proteins

Cells were lysed in a modified lysis buffer (50 mM Tris pH 7.4, 150 mM NaCl, 1% NP-40, 1 mM EDTA, 50 mM NaF, 10 mM β-glycerophosphate, 10 nM calyculin A, 1 mM Na3VO4, and protease inhibitors), followed by SDS-PAGE and western blotting analysis as previously described^{55 (link)}. The primary antibodies against STAG2 (Santa Cruz, SC-81852), IRF9 (Cell Signaling, #76684), IRF7 (Cell Signaling, #4920), USP18 (Cell Signaling, #4813), ISG15 (Santa Cruz, SC-166755), IRF1 (Cell Signaling, #8478), IRF3 (Cell Signaling, #11904), GAPDH (Cell Signaling, #2118), GAPDH (Cell Signaling, #51332), STAG1 (Novus Biologicals, NB100-298), PD-L1 (R&D Systems, AF156), CTCF (Cell Signaling, #2899), and Flag M2 (Sigma, F3165) were used. All primary antibodies were used at a 1:1,000 dilution, with the exception of GAPDH (1:3000) and PD-L1 (1:200).