Chemotaxis

Motile organisms generally use transmembrane receptor-mediated sensory mechanisms to monitor changes in environmental conditions and control migration toward favorable locations. While the motility mechanism may differ, virtually all motile bacteria employ essentially the same signal transduction mechanisms to couple attractant- and repellent-induced changes in chemoreceptor conformation to appropriate motor chemotaxis responses. The interacting proteins that constitute the chemotaxis signaling system function to control both the initial excitation response and the subsequent adaptations over time. Although Escherichia coli has been the archetype for understanding the molecular events that underlie excitation and adaptation in bacterial chemotaxis, in recent years research on several other bacterial species have revealed unique features that represent novel variations on the basic E. coli theme.