Fig. 6: Mitochondrial dysfunction leads to Mff phosphorylation and impaired antiviral response.

a WT MEFs were treated with the respiratory inhibitors rotenone (Rot, 0.5 μM) or antimycin A (AA, 1 μM) or the ATP synthase inhibitor oligomycin (Oligo, 1 μM) for 5 or 30 min. Whole-cell lysates were analyzed by immunoblotting using antibodies against the indicated proteins. AICAR (2 mM) or compound C (20 μM) was used as an AMPK activator or inhibitor, respectively. DMSO: dimethyl sulfoxide. b qRT-PCR analysis of IFN-β mRNA with or without poly(I:C)-LMW in WT MEFs and Mff KO MEFs stably expressing FLAG-Mff S146A. Cells were pretreated with or without oligomycin (Oligo, 1 μM) for 30 min and then transfected with poly(I:C)-LMW (1 μg/mL) in the absence (−) or presence (+) of oligomycin for 8 h. Data represent means ± SEM of two independent experiments (n = 4, P values; two-tailed unpaired t test). c Immunoblot analyses of Mff and Mff phosphorylation in WT MEFs and Mff KO MEFs stably expressing FLAG-Mff S146A with or without oligomycin (1 μM, 30 min). The indicated letters (a, b, c) correspond to the endogenous Mff bands observed in WT MEFs. d HeLa cells were transfected with control or Mfn1/2 siRNA and cultured for 72 h. The cells were transfected with or without poly(I:C)-LMW (1 μg/mL) for 4 h, and IFN-β induction was analyzed by qRT-PCR. Data represent means ± SEM of three independent experiments (n = 3, P values; two-tailed unpaired t test). e Analysis of Mff phosphorylation by immunoblotting using anti-phospho-Mff and anti-Mff antibodies in HeLa cells with the indicated RNAi. The efficiency of RNAi and AMPK activation were also examined by each antibody. f Working hypothesis for how mitochondrial dysfunction leads to the suppression of the antiviral response by the AMPK–Mff axis. Immunoblot analyses were repeated independently three times with similar results. Source data are provided as a Source data file.