In the Torres lab, I will explore how toxins produced by the bacterium Staphylococcus aureus damage tissues and precipitate sepsis. The microbe S. aureus is the culprit behind a variety of illnesses, from toxic shock syndrome to life-threatening infections of the heart, bones, and lungs. Part of what makes S. aureus so harmful is the toxins it secretes, which bind to receptors on the surface of host cells and punch holes in their membranes. Although these toxins commonly target immune cells, the Torres lab recently discovered that they also bind to DARC, a receptor found on the endothelial cells that line blood vessels. Now, using a range of cutting-edge techniques in cell and molecular biology, microbial genetics and physiology, and microscopy, I will characterize the mechanisms by which interaction with DARC allows the toxins to destroy endothelial cells, disrupt the endothelial lining of blood vessels, and promote the formation of abscesses that enable bacterial growth and dissemination in mice. This work could guide new strategies for combating infection with S. aureus or other toxin-secreting microbes.