Grant: Operating Grant

Many bacteria hold onto surfaces using long hair-like filaments called pili. Without these filaments, they can't initiate infections very easily because they are readily swept away. Some bacteria use their pili as minature grappling hooks, to move along surfaces. The bacteria extend the pili, hook them onto a surface, and retract them into the cell, pulling themselves forward. This movement is important during infection because it allows the bacteria to spread rapidly away from the initial point of contact. Mutations that paralyze the pili so they can't retract make the bacteria unable to cause disease. In this grant application, we propose to study the components that make up the filaments. We want to know exactly what the filaments are composed of, how the components are assembled and disassembled during extension and retraction, and how expression of the components is controlled, so we can block these processes. Some bacteria decorate their pili with sugars, and we recently found out that they do this because it protects them from predators called bacteriophages. Bacteriophages can infect bacteria by hitching a ride on the pili while they're retracted, so the bacteriophages are pulled inside the bacteria and kill them. The sugars prevent many bacteriophages from sticking to pili, but some have figured out how to get around this protective shield. Those types of bacteriophages will be used as tools, to show us where the vulnerable parts of the pili are. Together, these studies will help us to find new ways to interfere with the production or the function of pili, which in turn have potential to reduce bacterial infections.