Figure 5

MAVS degradation is required to release into the cytosol a signaling complex involved in IRF3 activation. (A) HeLa cells were infected with SeV H4 in the presence or the absence of MG132. At various times after infection, cytosolic fraction and mitochondrial fraction were prepared. MAVS, TRAF3, p-IRF3, IRF3, p-IκBα, IκBα NEMO and TBK1 were analyzed in each fraction by immunoblotting. Actin and VDAC were used as a protein loading control for cytosol fraction and mitochondrial fraction, respectively. (B) HeLa cells were infected or not with SeV H4 for 8 hr in the presence or the absence of MG132. Co-localization (yellow) of TBK1 (green) with mitochondria (red) was observed by immunofluorescence. Line scans show the fluorescence intensities of TBK1 (green) and mitochondria (red) along the selected line. (C) Control or MAVS siRNA were transfected into HeLa cells for 72 hr. Then, HeLa cells were infected or not with SeV H4 for 8 hr in the presence or the absence of MG132. Co-localization (yellow) of TBK1 (green) with mitochondria (red) was observed by immunofluorescence. Line scans show the fluorescence intensities of TBK1 (green) and mitochondria (red) along the selected line.