G3BP1 and infection: To further validate that eIF2α remains unphosphorylated during infection, we also confirmed the absence of downstream stress granule formation in RSV-infected cells by indirect immunofluorescent staining using stress granule markers PABP and G3BP (Supplementary Figs. S1D, E) [38], which is in stark contrast with NaAsO2-treated cells (Supplementary Fig. S1F).