RESUMO
The bacterial chemotaxis system is one of the best-understood cellular pathways and serves as the model for signal transduction systems. Most chemotaxis research has been conducted with transmembrane chemotaxis systems from Escherichia coli and has established paradigms of the system that were thought to be universal. However, emerging research has revealed that many bacteria possess alternative features of their chemotaxis system, demonstrating that these systems are likely more complex than previously assumed. Here, we compare the canonical chemotaxis system of E. coli with systems that diverge in supramolecular architecture, sensory mechanisms, and protein composition. The alternative features have likely evolved to accommodate chemical specificities of natural niches and cell morphologies. Collectively, these studies demonstrate that bacterial chemotaxis systems are a rapidly expanding field that offers many new opportunities to explore this exceedingly diverse system.
RESUMO
IMPORTANCE: A new class of bacterial protein sensors monitors intracellular levels of S-adenosylmethionine to modulate cell morphology, chemotaxis, and biofilm formation. Simultaneous regulation of these behaviors enables bacterial pathogens to survive within their niche. This sensor, exemplified by Treponema denticola CheWS, is anchored to the chemotaxis array and its sensor domain is located below the chemotaxis rings. This position may allow the sensor to directly interact with the chemotaxis histidine kinase CheA. Collectively, these data establish a critical role of CheWS in pathogenesis and further illustrate the impact of studying non-canonical chemotaxis proteins.