1. Bacterial chemotaxis: The five sensors of a bacterium
Thorsten W Grebe, Jeff Stock 
Current Biology 
Volume 8, Issue 5, Pages R154-R157 (February 1998)
DOI: /S (98)

2. Figure 1
The E. coli chemotaxis system. Stimulus molecules diffuse through the outer membrane into the periplasm, where they bind to their respective receptors either directly or indirectly via periplasmic binding proteins. The chemotaxis receptors signal through the inner membrane into the cytoplasm, where they interact with the adaptor protein CheW and the kinase CheA. The aerotaxis receptor, Aer, apparently receives intracellular redox signals through its flavin-binding domain, and is thought to interact with the electron transport chain. The chemotaxis system can adapt to changes in attractant or repellent concentrations by covalently modifying the membrane receptors. The methyltransferase CheR transfers methyl groups from S-adenosylmethionine (AdoMet) to conserved glutamate residues on the cytoplasmic signaling domains of the chemotaxis receptors. The methylesterase CheB removes these groups when activated through phosphorylation by CheA. Enzyme I (Pts I) of the phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) binds and inhibits CheA when a variety of hexoses are transported into the cell. All chemotaxis signals are ultimately integrated at the level of phosphorylation of the response regulator CheY, which directly interacts with the flagellar motor.
Current Biology 1998 8, R154-R157DOI: ( /S (98) )