CADHERIN EXPRESSION IS REQUIRED FOR THE SPREAD OF SHIGELLA-FLEXNERI BETWEEN EPITHELIAL-CELLS

Shigella flexneri, a gram-negative pathogen, invades the human colonic epithelium. After entering epithelial cells, bacteria escape into the cytoplasm, move intracellularly, and pass from cell to cell. The bact erium diverts actin and associated actin-binding proteins to generate a cytoskeleton-based motor that pushes forward the bacterium. As the m oving bacterium reaches the inner face of the host-cell cytoplasmic me mbrane, a protrusion forms that allows passage of this bacterium into a neighboring cell. We show here that components of the intermediate j unction are used by the bacterium to allow this passage. Using S180, a mouse fibroblastic sarcoma cell line that does not produce cell adhes ion molecules (CAM), and S180L and S180cadN, the same cell line transf ected with L-CAM and N-cadherin cDNA, respectively, we demonstrate tha t expression of a cadherin is required for cell-to-cell spread to occu r.