SARS-CoV-2 N protein interacts with TAB2 and TAB3. (A) Immunoprecipitation (IP) (anti-Flag) and immunoblot (IB) analysis of the interaction between Flag-TAB1/TAB2/TAB3/TAK1 and Myc-SARS-CoV-2 N protein in co-transfected HEK293T cells. (B) Immunoprecipitation (anti-Flag) and immunoblot analysis of the interaction between Flag-SARS-CoV-2 N protein and HA-TAB1/TAB2/TAB3/TAK1 in co-transfected HEK293T cells. (C) His-SARS-CoV-2 N protein, purified from E. coli, was incubated with E. coli–purified GST-TAK1/TAB2/TAB3 proteins for 6 h, the mixture was subjected to immunoprecipitation (anti-His) and immunoblot analysis. (D) HeLa cells were transfected with plasmids encoding DsRed-SARS-CoV-2 N and GFP-TAB2/TAB3 for 24 h. Nucleus marker DAPI (blue), DsRed-SARS-CoV-2 N (red), and GFP-TAB2/TAB3 (green) were then visualized with confocal microscopy. Scale bars, 10 μm. (E) HEK293T cells were transfected with the plasmid encoding Flag-SARS-CoV-2 N protein for 48 h, followed by TNF-α treatment for 4 h. Lysates were subjected to immunoprecipitation (anti-SARS-CoV-2 N protein) and immunoblot analysis. (F) Caco-2 cells were infected with SARS-CoV-2 at an MOI of 0.02 for 24 h. Lysates were subjected to immunoprecipitation (anti-SARS-CoV-2 N protein) and immunoblot analysis. (G and H) Huh7 cells were infected with SARS-CoV-2 at an MOI of 0.05 for 24 and 48 h, Nucleus marker DAPI (blue), SARS-CoV-2 N (red), and TAB2 (G)/TAB3 (H) (green) were then visualized with confocal microscopy. Scale bars, 20 μm. Data are done at least twice, and one representative is shown. Source data are available for this figure: SourceData F3.