Research

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. 

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 remodels the plasma membrane to move from cell to cell. 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. 

S. flexneri form plasma membrane protrusions during cell-to-cell spread. S. flexneri (green), plasma membrane (red). The formation of the protrusion is necessary to enable the pathogen to spread into neighboring cells.

2. Many bacterial pathogens deliver virulence proteins, known as effector proteins, into epithelial cells using a specialized, syringe-like apparatus known as a type 3 secretion system.  The effector proteins reprogram host signaling pathways, promoting the infection process. The delivery of these effector proteins by S. flexneri is essential to enable the pathogen’s invasion of cells and spread between cells. The lab is 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 system and for the virulence of many bacterial pathogens and viruses. The lab is interested understanding the mechanisms by which intermediate filaments contribute to infection.