About
Bacteria are nearly ubiquitous, play vital roles in industry and the environment, and are crucial factors for health and disease of all organisms. They are also small, tractable cells that are ideal to study biological processes. Chemotaxis allows motile bacteria, including some pathogens, to monitor their environment and swim toward nutrients and away from toxins. Due to its relative simplicity, the bacterial chemotaxis system serves as a paradigm for signal transduction pathways in general. Chemical signals bind to chemoreceptors, which are typically found at the cell poles and organize into highly cooperative, ordered arrays. These chemosensory arrays ultimately control whether the cell moves forward or changes direction. The chemotaxis system in the model species E. coli is now structurally well understood. This detailed knowledge can be used for practical applications. For instance, this signalling system provides an ideal platform to design biosensors. As such, we are currently developing a Neuroblastoma cancer screen based on the ability of the E. coli chemoreceptor Tsr to quickly detect a marker molecule for the disease.
Additionally, it is becoming increasingly clear that there is an underappreciated variability of chemotaxis systems among motile bacteria. We are especially interested in the chemotaxis systems of two pathogenic bacteria: Vibrio cholerae and Treponema denticola, human pathogens that use their chemotaxis sensing system for infectivity. We discovered recently that the organization of both of these pathogens is structurally distinct from E.coli (Muok et al., 2020b; Yang et al., 2018; Yang and Briegel, 2019). Most recently, we uncovered an alternative signalling pathway bypassing the chemoreceptors (Muok et al., 2023). We are investigating these alternate architectures and their implications in the pathogenicity of these organisms.