Role of stathmin microtubule-destabilizing activity in Shigella flexneri motility and tunneling

Abstract

The infection of the intestinal mucosa by Shigella bacteria is a global health issue resulting in a variety of potentially life-threatening gastrointestinal complications. Their unique method of intracellular motility depends on microtubule destabilization to clear the dense host cytoskeletal network in a process called tunneling. It is hypothesized that the host protein stathmin may play a role in this process, due to its tubulin-sequestering capability. This proposal aims to provide potential methodologies to elucidate the function of stathmin with respect to Shigella flexneri motility. Three experiments are proposed, involving comparisons between human intestinal epithelial cell strains under varying levels of stathmin expression, each infected with S. flexneri. Respectively, the experiments examine tunnel widths via electron microscopy, microtubule densities via imaging fluorescence correlation spectroscopy, and bacterial movement patterns via live fluorescence microscopy. If microtubule destabilization and movement is impaired in null stathmin strains, as predicted, such findings may inform a novel therapeutic target for Shigellosis by preventing internal spreading. This is particularly significant in our current landscape, as antibiotic-resistant strains of Shigella are growing increasingly prevalent.