MODULATION OF BACTERIAL ENTRY INTO EPITHELIAL-CELLS BY ASSOCIATION BETWEEN VINCULIN AND THE SHIGELLA IPAA INVASIN

Shigella flexneri is the causative agent of bacillary dysentery in hum ans. Shigella invasion of epithelial cells is characterized by cytoske letal rearrangements and formation of cellular projections engulfing t he bacterium in a macropinocytic process. We show here that vinculin, a protein involved in linking actin filaments to the plasma membrane, is a direct target of Shigella during cell invasion. IpaA, a Shigella protein secreted upon cell contact, rapidly associates with vinculin d uring bacterial invasion. Although defective for cell entry, an ipaA m utant is still able to induce foci of actin polymerization, but differ s from wild-type Shigella in its ability to recruit vinculin and a-act inin. Presumably, IpaA-vinculin interaction initiates the formation of focal adhesion-like structures required for efficient invasion.