ATF6 cleavage assay

HuH7 cells were transfected as described above with the plasmid p3xFlag-ATF6 together with empty vector (pCAGGS) (2 µg plasmid DNA/6-well). To monitor ATF6 cleavage, we utilized the Flag-tagged ATF6 construct p3xFLAG-ATF6, a gift from Ron Prywes (Addgene plasmid #11975) [32]. To stimulate ATF6 cleavage, cells were treated with 1 mM dithiothreitol for 30 min (DTT, Sigma-Aldrich, D9779) or transfected with plasmids encoding MARV proteins. The cells were analysed by Western blotting at 48 h p.t.