Activator for both CDC42 and RAC1 by directly interacting with these Rho GTPases and acting as a guanine nucleotide exchange factor (GEF). This activation results in actin cytoskeleton rearrangements and stimulates membrane ruffling, thus promoting bacterial entry into non-phagocytic cells. Active in pH ranges of 3.5-10.5. Monomer (Probable). Interacts with human CDC42. Secreted via the bsa type III secretion system. Immunogenic protein that elicits T-cell-mediated immunity in mice. Belongs to the GEF (guanine exchange factor) SopE family.