SUMO1 and infection: A weak, yet consistent reduction in the level of SUMO1-modified proteins was readily visible 30 min post-infection as shown by a ~ 25% decrease in the total amount of SUMO1 conjugates and a concomitant ~20% accumulation of free SUMO1 (Figure 1A, Figure 1—figure supplement 1B and Figure 1—figure supplement 1—source data 1).