title: Coordinated regulation of multiple flagellar motors by theEscherichia colichemotaxis system.
abstract: Escherichia colicells swim toward a favorable environment by chemotaxis. The chemotaxis system regulates the swimming behavior of the bacteria by controlling the rotational direction of their flagellar motors. Extracellular stimuli sensed by chemoreceptors are transduced to an intracellular signal molecule, phosphorylated CheY (CheY-P), that switches the rotational direction of the flagellar motors from counterclockwise (CCW) to clockwise (CW) or from CW to CCW. Many studies have focused on identifying the proteins involved in the chemotaxis system, and findings on the structures and intracellular localizations of these proteins have largely elucidated the molecular pathway. On the other hand, quantitative evaluations of the chemotaxis system, including the process of intracellular signaling by the propagation of CheY-P and the rotational switching of flagellar motor by binding of CheY-P molecules, are still uncertain. For instance, scientific consensus has held that the flagellar motors of anE. colicell switch rotational direction asynchronously. However, recent work shows that the rotational switching of any two different motors on a singleE. colicell is highly coordinated; a sub-second switching delay between motors is clearly correlated with the relative distance of each motor from the chemoreceptor patch located at one pole of the cell. In this review of previous studies and our recent findings, we discuss the regulatory mechanism of the multiple flagellar motors on an individualE. colicell and the intracellular signaling process that can be inferred from this coordinated switching.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Fukuoka
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishijima
keywords: CheY; bacteria; receptor; rotary motor; signal transduction