The Russo lab is interested in understanding how bacterial pathogens interact with their hosts. As a model, we investigate the pathogenesis of Shigella flexneri, which infects cells of the colon and causes diarrhea in humans.  S. flexneri invades epithelial cells and spreads between the epithelial cells. This organism delivers virulence proteins, known as effector proteins, into epithelial cells using a specialized, syringe-like apparatus known as a type 3 secretion system.  The delivered effector proteins reprogram signaling pathways in the epithelial cells enabling the bacterium to create and maintain an intracellular niche. 

The research in the laboratory is focused on three areas:

1. S. flexneri has a complex intracellular lifecycle. It induces its uptake into cells, polymerizes actin for motility, subverts cellular processes evolved to detect and kill pathogens, and reprograms cellular pathways to move between cells. To understand how S. flexneri induces these processes, we are interested in determining the bacterial and host genes required for S. flexneri infection and to define the molecular mechanisms by which they function.
2. The type 3 secretion system is essential for S. flexneri infection. We are interested in determining the mechanisms required for type 3 secretion activity.  
3. Intermediate filaments are structural proteins present in mammalian cells. They also are required for the activity of type 3 secretion and for the virulence of many bacterial pathogens and viruses. The lab is interested understanding the mechanisms by which intermediate filaments contribute to infection.