a Co-IP analysis of WT K63- and K63 mutant (K63R)-linked polyubiquitination of STAT1 mediated by RNF220 in HEK293T cells transfected with plasmids as indicated. b Co-IP analysis of the K63-linked polyubiquitination of STAT1 mediated by WT RNF220, RING domain deletion mutant (-R), and catalytic site mutant (M) in HEK293T cells transfected with plasmids as indicated. c, d Co-IP analysis WT and the K63-linked polyubiquitination of endogenous STAT1 in WT and Rnf220+/– BMDMs in response to A. baumannii infection (30 MOI, c) and INF-β treatment (2 ng/ml, d) for indicated times. e Co-IP analysis of the K63-linked polyubiquitination of full length and truncated STAT1 mediated by RNF220 in HEK293T cells transfected with plasmids as indicated. f Co-IP analysis of the K63-linked polyubiquitination of WT STAT1 and STAT1 mutants (K13R, K40R, K85R, K87R, K110R, and K114R) mediated by RNF220 in HEK293T cells transfected with plasmids as indicated. Data represent two independent experiments.