Natural variants of Listeria monocytogenes internalin B with different ability to stimulate cell proliferation and cytoskeleton rearrangement in HEp-2 cells

The Gram-positive bacterium Listeria monocytogenes is a facultative intracellular pathogen. The InlB protein is required for L. monocytogenes active invasion into epithelial cells. InlB interacts with the surface tyrosine kinase receptor c-Met. Activation of c-Met by its natural ligand, hepatocyte growth factor, induces intracellular signaling pathways and causes cell proliferation and/or migration. Interactions of InlB with c-Met in the course of infection activates the receptor and results in cytoskeleton rearrangement and bacterial uptake. In this study, we investigated the potential of the purified InlB protein as the c-Met ligand causing cell proliferation. Three distinct InlB variants have been compared. These variants were previously described in L. monocytogenes strains isolated from different sources. The variants were shown to be different in the induction of HEp-2 cell proliferation. In addition, the InlB variants differed in their potential to induce cytoskeleton rearrangements.