HEK293T cells transiently transfected with plasmids encoding Flag-STING, Myc-HOIP and HA-HOIL-1L, were lysed with buffer (20 mM Na2HPO4, 20 mM NaH2PO4, 1% NP-40, 2 mM EDTA) supplemented with 1 mM DTT, 5 mM NEM, complete protease inhibitor cocktail, PhosSTOP and 0.1% SDS. The lysates were incubated with Anti-Flag M2 Affinity Gel. The bound material was eluted with 0.1 M glycine-HCl pH 2.7, separated by electrophoresis in a 10% gel, and stained with Bio-Safe Coomassie and then for mass spectrometry analysis