RAC1 and infection: By contrast, infection with yopEL109A, which has partially reduced RhoA-GAP activity (about 70% of WT YopE) and normal Rac1-GAP activity,33 caused M cell extrusion similar to WT 37°C and had a Yptb internalization phenotype similar to WT 37°C (Figure 6h-j, Table S4).