“…The production of PKR and MAVS KO HeLa R19 cells by CRISPR-Cas9 gene editing has been described elsewhere [ 70 , 71 ]. HeLa M WT, RSK-1/2/3 triple KO, and RSK-2 reconstituted cells were a kind gift from dr. prof. T. Michiels (de Duve Institute, Université Catholique de Louvain, Belgium) and have been described in [ 53 ]. All cell lines were cultured in Dulbecco’s Modified Eagle Medium (high glucose, GlutaMAX, ThermoFischer Scientific, Waltham, MA, USA), supplemented with 10% fetal calf serum (FCS; GE Healthcare Bio-Sciences, Chicago, IL), 100 U/mL penicillin and 100 μg/mL streptomycin (Gibco, Paisley, United Kingdom) and kept in a humidified incubator at 37°C and 5% CO 2 .…”