The Federle Lab

Discovering Languages of Pathogens...

We are focused on understanding how bacteria coordinate gene expression across a population using cell-to-cell communication.  Many important behaviors and activities of bacteria, including the ability to become virulent, to form biofilms, or to enter the competent state, are controlled through intercellular communication. This process, referred to as quorum sensing, facilitates inter-bacterial communication and the ability to communicate between bacteria and host, thus potentially affecting the health of the host.  Intercellular communication relies on secreted signaling molecules (which we refer to as pheromones) that are detected by various types of receptor proteins in recipient cells.  Pheromone detection potentiates differential gene expression.


We have identified and characterized new quorum sensing pathways in Streptococcal species.  The protein family known as Rgg is central to these signaling pathways, dually acting as cytoplasmic receptors of peptide pheromones and transcriptional regulators.  Rgg proteins contribute to a complex quorum-sensing network in Streptococcus pyogenes (Group A Streptococcus, or GAS). GAS is responsible for a wide variety of diseases that range in severity from mild cases of impetigo and pharyngitis (strep throat), to life-threatening necrotizing fasciitis, myonecrosis, and toxic shock. Acute rheumatic fever and rheumatic heart disease are a leading cause of death from streptococcal infections in developing countries. We are currently investigating the molecular nature of the streptococcal quorum sensing network, and its role in controlling virulence factors that contribute to disease. Our studies will lead to the development of new methodologies that disrupt infectious diseases by interfering with bacteria’s ability to coordinate their assault on the human body.


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