LcrQ and SycH function together at the Ysc type III secretion system in <i>Yersinia pestis</i> to impose a hierarchy of secretion

Wulff-Strobel, Christine R.; Williams, A W; Straley, Susan C.

doi:10.1046/j.1365-2958.2002.02752.x

Cited by 98 publications

(90 citation statements)

References 43 publications

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“…9). This model is similar to a proposed model for Yersinia pestis type III effector secretion, where it is thought that LcrQ and its chaperone SycH function together to mediate a hierarchy of secretion (45).…”

Section: Discussionsupporting

confidence: 69%

Hierarchical Delivery of an Essential Host Colonization Factor in Enteropathogenic Escherichia coli

Thomas

Deng

Baker

et al. 2007

Journal of Biological Chemistry

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Section: Discussionsupporting

confidence: 69%

Hierarchical Delivery of an Essential Host Colonization Factor in Enteropathogenic Escherichia coli

Thomas

Deng

Baker

et al. 2007

Journal of Biological Chemistry

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“…in the presence of other chaperone-effector complexes). Additional evidence for competition between chaperone-effector complexes exists (35).…”

Section: Discussionmentioning

confidence: 99%

The Type III Secretion Chaperone SycE Promotes a Localized Disorder-to-Order Transition in the Natively Unfolded Effector YopE

Rodgers

Gamez

Riek

et al. 2008

Journal of Biological Chemistry

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Many virulence-related, bacterial effector proteins are translocated directly into the cytosol of host cells by the type III secretion (TTS) system. Translocation of most TTS effectors requires binding by specific chaperones in the bacterial cytosol, although how chaperones promote translocation is unclear. To provide insight into the action of such chaperones, we studied the consequences of binding by the Yersinia chaperone SycE to the effector YopE by NMR. These studies examined the intact form of the effector, whereas prior studies have been limited to well ordered fragments. We found that YopE had the characteristics of a natively unfolded protein, with its N-terminal 100 residues, including its chaperone-binding (Cb) region, flexible and disordered in the absence of SycE. SycE binding caused a pronounced disorder-to-order transition in the Cb region of YopE. The effect of SycE was strictly localized to the Cb region, with other portions of YopE being unperturbed. These results provide stringent limits on models of chaperone action and are consistent with the chaperone promoting formation of a three-dimensional targeting signal in the Cb region of the effector. The target of this putative signal is unknown but appears to be a bacterial component other than the TTS ATPase YscN.

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“…Furthermore, in Yersinia species, expression of genes encoding both components of the TTS apparatus and effectors is increased under conditions of active secretion (Lambert de Derouvroit et al, 1992;Rimpilainen et al, 1992). The mechanism by which the TTS apparatus activity is transmitted to VirF has not yet been elucidated, but also involves TTS chaperones (Francis et al, 2001;Wulff-Strobel et al, 2002). Control of gene transcription by the TTS apparatus activity is likely to be a general feature of TTS systems and is strong evidence that a temporal regulation of expression of effectors is a key element in the function of TTS systems (Francis et al, 2002;Miller, 2002).…”

Section: Discussionmentioning

confidence: 99%

Analysis of virulence plasmid gene expression defines three classes of effectors in the type III secretion system of Shigella flexneri

Gall

Mavris

Martino³

et al. 2005

Microbiology

115

174

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Proteins directly involved in entry and dissemination of Shigella flexneri into epithelial cells are encoded by a virulence plasmid of 200 kb. A 30-kb region (designated the entry region) of this plasmid encodes components of a type III secretion (TTS) apparatus, substrates of this apparatus and their dedicated chaperones. During growth of bacteria in broth, expression of these genes is induced at 37 6C and the TTS apparatus is assembled in the bacterial envelope but is not active. Secretion is activated upon contact of bacteria with host cells and is deregulated in an ipaB mutant. The plasmid encodes four transcriptional regulators, VirF, VirB, MxiE and Orf81. VirF controls transcription of virB, whose product is required for transcription of entry region genes. MxiE, with the chaperone IpgC acting as a co-activator, controls expression of several effectors that are induced under conditions of secretion. Genes under the control of Orf81 are not known. The aim of this study was to define further the repertoires of virulence plasmid genes that are under the control of (i) the growth temperature, (ii) each of the known virulence plasmid-encoded transcriptional regulators (VirF, VirB, MxiE and Orf81) and (iii) the activity of the TTS apparatus. Using a macroarray analysis, the expression profiles of 71 plasmid genes were compared in the wild-type strain grown at 37 and 30 6C and in virF, virB, mxiE, ipaB, ipaB mxiE and orf81 mutants grown at 37 6C. Many genes were found to be under the control of VirB and indirectly of VirF. No alteration of expression of any gene was detected in the orf81 mutant. Expression of 13 genes was increased in the secretion-deregulated ipaB mutant in an MxiE-dependent manner. On the basis of their expression profile, substrates of the TTS apparatus can be classified into three categories: (i) those that are controlled by VirB, (ii) those that are controlled by MxiE and (iii) those that are controlled by both VirB and MxiE. The differential regulation of expression of TTS effectors in response to the TTS apparatus activity suggests that different effectors might be required at different times following contact of bacteria with host cells. INTRODUCTIONBacteria of Shigella species are responsible for shigellosis, a human disease characterized by the destruction of the colonic epithelium. Shigellae and enteroinvasive Escherichia coli both contain a virulence plasmid (VP) of approximately 200 kb that encodes most proteins directly involved in entry and dissemination of bacteria into epithelial cells. Sequence analysis of the VP pWR100 (Buchrieser et al., 2000) and its derivative pWR501 (Venkatesan et al., 2001) from a Shigella flexneri strain of serotype 5 and the VP pCP301 (Jin et al., 2002) from an S. flexneri strain of serotype 2a indicated that the VP is composed of a mosaic of approximately 100 genes and numerous insertion sequences. The VP genes exhibit a G+C content from 30 to 60 mol%, suggesting that they were acquired from different sources. The current model of the TTS pathway prop...

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LcrQ and SycH function together at the Ysc type III secretion system in Yersinia pestis to impose a hierarchy of secretion

Cited by 98 publications

References 43 publications

Hierarchical Delivery of an Essential Host Colonization Factor in Enteropathogenic Escherichia coli

Hierarchical Delivery of an Essential Host Colonization Factor in Enteropathogenic Escherichia coli

The Type III Secretion Chaperone SycE Promotes a Localized Disorder-to-Order Transition in the Natively Unfolded Effector YopE

Analysis of virulence plasmid gene expression defines three classes of effectors in the type III secretion system of Shigella flexneri

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