A dynamic-signaling-team model for chemotaxis receptors in Escherichia coli.
Publication Year
2010
Type
Journal Article
Abstract
The chemotaxis system of Escherichia coli is sensitive to small relative changes in ambient chemoattractant concentrations over a broad range. Interactions among receptors are crucial to this sensitivity, as is precise adaptation, the return of chemoreceptor activity to prestimulus levels in a constant chemoeffector environment through methylation and demethylation of receptors. Signal integration and cooperativity have been attributed to strongly coupled, mixed teams of receptors, but receptors become individually methylated according to their ligand occupancy states. Here, we present a model of dynamic signaling teams that reconciles strong coupling among receptors with receptor-specific methylation. Receptor trimers of dimers couple to form a honeycomb lattice, consistent with cryo-electron microscopy (cryoEM) tomography, within which the boundaries of signaling teams change rapidly. Our model helps explain the inferred increase in signaling team size with receptor modification, and indicates that active trimers couple more strongly than inactive trimers.
Keywords
Journal
Proc Natl Acad Sci U S A
Volume
107
Issue
40
Pages
17170-5
Date Published
10/2010
ISSN Number
1091-6490
Alternate Journal
Proc. Natl. Acad. Sci. U.S.A.
PMID
20855582