Apyrase, the product of the virulence plasmid-encoded phoN2 (apy) gene of Shigella flexneri is necessary for proper unipolar IcsA localization and for efficient intercellular spread.

The role in virulence of the Shigella flexneri ospB-phoN2 operon has been evaluated. Here we confirm that OspB is an effector and show that apyrase, the product of phoN2, may be a virulence factor, since it is required for efficient intercellular spreading. Apyrase may be important in a deoxynucleoside triphosphate-hydrolyzing activity-independent manner, suggesting that it may act as an interaction partner in the process of IcsA localization.