CheA–Receptor Interaction Sites in Bacterial Chemotaxis

Wang, Xiqing; Vu, Anh; Lee, Kwang-Woon; Dahlquist, Frederick W.

doi:10.1016/j.jmb.2012.05.023

Cited by 45 publications

(91 citation statements)

References 50 publications

(73 reference statements)

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“…1B). This P3-P4 linker has been shown to be central to kinase activity and control, specifically basal autophosphorylation, kinase activation, and initiation of longrange structural and dynamic changes impinging on the active site (21)(22)(23). Thus, the P3-P4 linker could be a conduit through which allosteric inhibition passes from an inhibited P4 catalytic domain to the P3 helical bundle, and from P3 to inhibit the P4' catalytic domain of the companion kinase protomer.…”

Section: Discussionmentioning

confidence: 99%

Selective allosteric coupling in core chemotaxis signaling complexes

Hazelbauer

2014

Proc. Natl. Acad. Sci. U.S.A.

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Bacterial chemotaxis is mediated by signaling complexes that sense chemical gradients and direct bacteria to favorable environments by controlling a histidine kinase as a function of chemoreceptor ligand occupancy. Core signaling complexes contain two trimers of transmembrane chemoreceptor dimers, each trimer binding a coupling protein CheW and a protomer of the kinase dimer. Core complexes assemble into hexagons, and these form hexagonal arrays. The notable cooperativity and amplification in bacterial chemotaxis is thought to reflect allosteric interactions in cores, hexagons, and arrays, but little is known about this presumed allostery. We investigated allostery in core complexes assembled with two chemoreceptor species, each recognizing a different ligand. Chemoreceptors were inserted in Nanodiscs, which rendered them water soluble and allowed isolation of individual complexes. Neighboring dimers in receptor trimers influenced one another's operational ligand affinity, indicating allosteric coupling. However, this coupling did not include the key function of kinase inhibition. Our data indicated that only one receptor dimer could inhibit kinase as a function of ligand occupancy. This selective allosteric coupling corresponded with previously identified structural asymmetry: only one dimer in a trimer contacts kinase and only one CheW. We suggest one of these dimers couples ligand occupancy to kinase inhibition. Additionally, we found that kinase protomers are allosterically coupled, conveying inhibition across the dimer interface. Because kinase dimers connect core complex hexagons, allosteric communication across dimer interfaces provides a pathway for receptor-generated kinase inhibition in one hexagon to spread to another, providing a crucial step for the extensive amplification characteristic of chemotactic signaling.transmembrane receptors | bacterial chemotaxis | allosteric coupling | histidine kinases | Nanodiscs

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Section: Discussionmentioning

confidence: 99%

Selective allosteric coupling in core chemotaxis signaling complexes

Hazelbauer

2014

Proc. Natl. Acad. Sci. U.S.A.

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“…These results suggest that both CheV1 and CheW cause CheA to be more active, with CheW triggering greater activation. Previous work has shown that CheA activation is maximal with coupling proteins (24,25).…”

Section: Chew and Chev1 Both Form Direct Interactions With Chea Andmentioning

confidence: 95%

Cooperation of two distinct coupling proteins creates chemosensory network connections

Abedrabbo

Castellon

Collins

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Although it is appreciated that bacterial chemotaxis systems rely on coupling, also called scaffold, proteins to both connect input receptors with output kinases and build interkinase connections that allow signal amplification, it is not yet clear why many systems use more than one coupling protein. We examined the distinct functions for multiple coupling proteins in the bacterial chemotaxis system of Helicobacter pylori, which requires two nonredundant coupling proteins for chemotaxis: CheW and CheV1, a hybrid of a CheW and a phosphorylatable receiver domain. We report that CheV1 and CheW have largely redundant abilities to interact with chemoreceptors and the CheA kinase, and both similarly activated CheA’s kinase activity. We discovered, however, that they are not redundant for formation of the higher order chemoreceptor arrays that are known to form via CheA–CheW interactions. In support of this possibility, we found that CheW and CheV1 interact with each other and with CheA independent of the chemoreceptors. Therefore, it seems that some microbes have modified array formation to require CheW and CheV1. Our data suggest that multiple coupling proteins may be used to provide flexibility in the chemoreceptor array formation.

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“…The tip contains determinants for binding CheA [9–11] and CheW [10, 12, 13] and for forming trimers of receptor dimers [14, 15]. The five E. coli members of the MCP family (Tar, Tsr, Tap, Trg, and Aer) have identical trimer contact residues, enabling low-abundance receptors (Tap, Trg, and Aer) to participate in signaling teams with high-abundance partners (Tar and Tsr) [15, 16].…”

Section: Structural Features Of Chemoreceptor Moleculesmentioning

confidence: 99%

Signaling and sensory adaptation in Escherichia coli chemoreceptors: 2015 update

Parkinson

Hazelbauer

Falke

2015

Trends in Microbiology

367

411

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Motile Escherichia coli cells track gradients of attractant and repellent chemicals in their environment with transmembrane chemoreceptor proteins. These receptors operate in cooperative arrays to produce large changes in the activity of a signaling kinase CheA in response to small changes in chemoeffector concentration. Recent research has provided much deeper understanding of the structure and function of core receptor signaling complexes and the architecture of higher-order receptor arrays, which in turn has led to new insights into the molecular signaling mechanisms of chemoreceptor networks. Current evidence supports a new view of receptor signaling in which stimulus information travels within receptor molecules through shifts in the dynamic properties of adjoining structural elements rather than through a few discrete conformational states.

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CheA–Receptor Interaction Sites in Bacterial Chemotaxis

Cited by 45 publications

References 50 publications

Selective allosteric coupling in core chemotaxis signaling complexes

Selective allosteric coupling in core chemotaxis signaling complexes

Cooperation of two distinct coupling proteins creates chemosensory network connections

Signaling and sensory adaptation in Escherichia coli chemoreceptors: 2015 update

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