AMPylation of Rho GTPases by Vibrio VopS Disrupts Effector Binding and Downstream Signaling

The Vibrio parahaemolyticus type III effector VopS is implicated in cell rounding and the collapse of the actin cytoskeleton by inhibiting Rho guanosine triphosphatases ( GTPases). We found that VopS could act to covalently modify a conserved threonine residue on Rho, Rac, and Cdc42 with adenosine 5 '- monophosphate ( AMP). The resulting AMPylation prevented the interaction of Rho GTPases with downstream effectors, thereby inhibiting actin assembly in the infected cell. Eukaryotic proteins were also directly modified with AMP, potentially expanding the repertoire of posttranslational modifications for molecular signaling.