EIF2AK2 and infection: To demonstrate that EMCV enhanced PKR conjugation to SUMO3 2 h post-infection and decreased PKR-SUMO3 modified forms 4 h post-infection, we performed Ni-NTA purifications in extracts from His-SUMO3 expressing cells uninfected and infected with EMCV for 2 h (Fig. 5c, left panel) or 4 h (Fig. 5c, right panel).