The Galán lab studies the structure and function of the bacterial injectisome, a molecular machine that allows infectious bacteria to inject virulence proteins into a host cell. A variety of disease-causing microbes—responsible for everything from pneumonia to the plague—make use of this multiprotein complex that acts as a syringe through which they inject toxins that manipulate host cell systems. Key to the assembly and operation of this complex machine is a structure called the “sorting platform,” which directs the addition of the “needle” to the syringe and determines the order in which bacterial proteins will pass through it. I will study the three-dimensional architecture of the sorting platform from Salmonella typhimurium, the bacterium that can cause gastroenteritis, and assess how its structure changes during the course of infection. These findings could provide additional detail on the initial steps of pathogenesis and lead to novel strategies for the treatment of a variety of infections.