FIG. 7.

(A) ExoS induced cell death in Drosophila S2 cells. Similar to its effect on mammalian cells, the cytotoxicity of ExoS in Drosophila S2 cells is dependent on its ADP-ribosylating activity (EA, ExosE381A; RK, ExoSR146K; RKEA, ExoSR146K/E381A). Wild type and ExoSRK killed essentially 100% transfected cells, whereas the ExoSEA and ExoSRKEA double mutants have dramatically reduced cytotoxic activity. (B) While increasing the level of dIAP1 significantly suppressed reaper-induced cell death, it had little effect on ExoS-induced cytotoxicity. The colors of the bar reflect the relative ratio between proapoptotic gene constructs and Diap1. For both panels A and B, the data are represented as averages (n = 5 and 4, respectively), and error bars indicate the SD.