Fig. 7: MAVS modification by 4-OI suppresses antiviral immunity.

a HEK293 cells pretreated with increasing 4-OI concentrations (75 and 125 μM) and transfected with GFP-tagged plasmids. Immunoblotting analyzes antiviral proteins. b, c Data from Runtsch et al.²⁹. THP1 cells treated with 4-OI (125 μM), prior challenge with IA-DTB, cell lysis, and measurement of modified cysteines by LC-MS. d 786-O cells treated with 125 μM of 4-OI-alk (4 or 24 h) with or without 4-OI (125 μM), followed by click chemistry and biotin enrichment. Samples before and after enrichment analyzed by anti-MAVS immunoblotting. e HEK293 cells pretreated or not with 4-OI (125 μM) and transfected with Flag-tagged MAVS together with GFP-tagged RIG-I or TBK1 as indicated. Whole-cell extracts prepared and immunoprecipitated with anti-Flag antibody M2; immunoprecipitated complexes or 5% input run on SDS-PAGE and probed with anti-GFP/anti-Flag antibodies. f, g Transient MAVS KO 786-O cells treated with 4-OI, then infected with VSVΔ51, analyzed by Western blot (f) and flow cytometry (g). h HEK293 cells transfected with a plasmid encoding Flag-tagged MAVS wt or mutant Flag-tagged MAVS C283A for 24 h. Subsequently, cells treated with 125 μM of alkynated 4-OI (4-OI-alk) for 4 h, followed by click chemistry and biotin enrichment. Samples before and after enrichment analyzed by anti-Flag immunoblotting. i HEK293 cells stimulated with 4-OI prior to transfection with MAVS wt or mutant C283A MAVS, analyzed by ISRE promoter luciferase activity. j HEK293 cells transfected with MAVS wt or mutant together with TBK1, treated with 4-OI, analyzed by immunoprecipitation and immunoblotting. Data from one representative experiment in (a), three independent experiments in (b, c), one representative experiment performed three times in (d), one experiment in (e, h, j). Data from one representative experiment out of two in (f). Data depicted as means ± SEM from two independent experiments performed in triplicates and quadruplicates in (g), two independent experiments in triplicates in (I). Statistical significance by one-way ANOVA for (g) and two-way ANOVA for (I). Vertical stacks of bands are not derived from the same membrane in (a, e, f, j). Source data provided in Source Data file.