Visualizing the Host-hijacking Toolkit of Pathogenic Bacteria

My research focuses on the molecular aspects of bacterial pathogenesis. Primarily we are interested in understanding the function of bacterial proteins involved in the sophisticated “biochemical cross-talk” between pathogen and host and which are critical for the survival and proliferation of the pathogen. This class, often collectively called ‘effectors’, includes bacterial proteins delivered into the host cell via specialized secretion systems. While these bacterial proteins have different mechanisms of delivery into the host cytoplasm, they all share the ability to alter host cellular pathways/systems to promote pathogenesis and contribute to virulence. Distantly related bacterial pathogens may harbor closely related effectors, suggesting that these effectors are targeting highly conserved host pathways and that one pathogenic mechanism can give rise to a multitude of diseases that range from bubonic plague in humans to fire blight in fruit trees. Thus, characterization of the specific functions of bacterial effectors will not only advance our general understanding of pathogenesis process but can also lead to discovery of novel eukaryotic signaling pathways. In my presentation I will describe our advances in understanding of molecular function of bacterial effectors hijacking host ubiquitin proteasome system (UPS), which has emerged as one of the main targets for effector proteins. While bacteria generally lack the UPS, the bacterial pathogens encode many effectors with UPS- specific functions with particularly large and diverse group mimicking the function of eukaryotic ubiquitin protein ligases also known as E3 enzymes.