Fig. 3.

PDZ Motifs 29-DEMI-32 and 39-KEALSDGI-46 of M2-2 protein suppress IRF-3 and NF-κB activation by inhibiting mitochondrial signalosome formation. (A). The effect of M2-2 on TRAF-activated signaling. A549 cells were transfected a luciferase reporter plasmid NF-κB-Luc (0.5 µg/well), a plasmid encoding TRAF5 or its control (0.5 µg/well), and a plasmid encoding hMPV M2-2 or its mutants, or a control vector (0.1 µg/well). After 30 h, cells were harvested for luciferase activity measurement. (B). The effect of motifs on the recruitment of TRAFs to mitochondrial compartment. A549 cells were infected with rhMPV-WT, rhMPV-E30M31, or rhMPV-E40L42D44, at MOI of 2, for 15 h and harvested to purify mitochondria. The abundance of mitochondria-associated MAVS, M2-2 and TRAF proteins was investigated by Western blot. Membranes were stripped and reprobed with anti-SDHA, as control for comparable loading of samples. Data shown are representative of two independent experiments.