RAC1 and infection: Similar to previous investigations (35), we infected HT-29 pmbYFP intestinal epithelial cells with WT S. flexneri, S. flexneri ΔicsB, or S. flexneri ΔipgB1, and at 5 hours of infection, we observed Rac1 was recruited to fewer DMVs in cells infected with S. flexneri ΔipgB1 (Fig. S7B through D and Table S3).