The Type II Secretion Pathway in Vibrio cholerae Is Characterized by Growth Phase-Dependent Expression of Exoprotein Genes and Is Positively Regulated by σ
            <sup>E</sup>

Zielke, Ryszard A.; Simmons, Ryan S.; Park, Bo R.; Nonogaki, Mariko; Emerson, Sarah C.; Sikora, Aleksandra E.

doi:10.1128/iai.01292-13

Cited by 22 publications

(26 citation statements)

References 51 publications

(79 reference statements)

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“…Concurrent with our experiments, another study found that two promoters were predicted to be upstream of epsC; the downstream promoter was predicted to be 70 dependent, while the upstream promoter was E dependent (26). Moreover, two V. cholerae DGCs were shown to induce an epsC-lux transcriptional fusion in E. coli (26).…”

mentioning

confidence: 70%

“…2). These transcriptional (26). In that study, the E 5= promoter was named P2, while the 70 3= promoter was named P1.…”

Section: Resultsmentioning

confidence: 99%

“…Previous reports have suggested that the eps gene cluster in V. cholerae is induced by c-di-GMP (26,33). To determine the mechanism of this regulation, we constructed a transcriptional fusion of a 628-bp region upstream of the first gene in the T2SS operon, epsC (referred to as PepsC), to the lux operon on the plasmid pBBRlux (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

et al. 2017

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Vibrio cholerae is a human pathogen that alternates between growth in environmental reservoirs and infection of human hosts, causing severe diarrhea. The second messenger cyclic di-GMP (c-di-GMP) mediates this transition by controlling a wide range of functions, such as biofilms, virulence, and motility. Here, we report that c-di-GMP induces expression of the extracellular protein secretion (eps) gene cluster, which encodes the type II secretion system (T2SS) in V. cholerae. Analysis of the eps genes confirmed the presence of two promoters located upstream of epsC, the first gene in the operon, one of which is induced by c-di-GMP. This induction is directly mediated by the c-di-GMP-binding transcriptional activator VpsR. Increased expression of the eps operon did not impact secretion of extracellular toxin or biofilm formation but did increase expression of the pseudopilin protein EpsG on the cell surface.IMPORTANCE Type II secretion systems (T2SSs) are the primary molecular machines by which Gram-negative bacteria secrete proteins and protein complexes that are folded and assembled in the periplasm. The substrates of T2SSs include extracellular factors, such as proteases and toxins. Here, we show that the widely conserved second messenger cyclic di-GMP (c-di-GMP) upregulates expression of the eps genes encoding the T2SS in the pathogen V. cholerae via the c-di-GMP-dependent transcription factor VpsR.KEYWORDS Vibrio cholerae, biofilm, VpsR, type II secretion, cyclic di-GMP V ibrio cholerae is a major bacterial pathogen responsible for the diarrheal disease cholera, causing an estimated 2.8 million infections each year resulting in approximately 91,000 deaths (1). V. cholerae is endemic to coastal waterways in tropical countries, where it persists in the environment as a biofilm on chitinous surfaces and periodically causes outbreaks in human populations. V. cholerae can rapidly spread and multiply under favorable environmental conditions, as seen in the recent 2010 Haiti outbreak (2). A fundamental property that allows V. cholerae to cause disease is its ability to transition from environmental reservoirs to human hosts. This transition is in part regulated by the second-messenger molecule cyclic di-GMP (c-di-GMP) (3-5).c-di-GMP is a nearly ubiquitous second-messenger molecule in bacteria that controls a range of physiological functions, including biofilm formation, motility, and virulence factor expression (6). c-di-GMP is synthesized by diguanylate cyclases (DGCs) (7) and degraded by phosphodiesterases (PDEs) (8,9). Together, these enzymes alter the concentration of c-di-GMP in the cell in response to environmental inputs. c-di-GMP has been shown to repress motility and virulence to promote a sessile, biofilmassociated lifestyle by stimulating the production of exopolysaccharide (EPS) matrix substances and adhesins while inhibiting flagellar activity or expression (3, 10-12). Levels of intracellular c-di-GMP have been proposed to be high in environmental

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confidence: 70%

“…2). These transcriptional (26). In that study, the E 5= promoter was named P2, while the 70 3= promoter was named P1.…”

Section: Resultsmentioning

confidence: 99%

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Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

et al. 2017

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“…The assays were conducted in 50 mM Tris-HCl, 150 mM NaCl, 5 mM CaCl 2 , pH 7.6, and 25 g/ml DQ gelatin for 10 min at 37°C using excitation and emission wavelengths of 485 Ϯ 10 and 530 Ϯ 15 nm, respectively. The detected change in fluorescence was normalized by either the optical density of the cultures (OD 600 ) or VchC concentration (28). The effect of different inhibitors, including 1,10-phenanothroline (5 mM), EDTA (5 mM), EGTA (5 mM), leupeptin (1 mM), phenylmethylsulfonyl fluoride (PMSF; 5 mM), N-methylmaleimide (5 mM), and benzamidine (5 mM), on VchC proteolytic activity also was studied.…”

Section: Methodsmentioning

confidence: 99%

A Metalloprotease Secreted by the Type II Secretion System Links Vibrio cholerae with Collagen

et al. 2015

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bVibrio cholerae is autochthonous to various aquatic niches and is the etiological agent of the life-threatening diarrheal disease cholera. The persistence of V. cholerae in natural habitats is a crucial factor in the epidemiology of cholera. In contrast to the well-studied V. cholerae-chitin connection, scarce information is available about the factors employed by the bacteria for the interaction with collagens. Collagens might serve as biologically relevant substrates, because they are the most abundant protein constituents of metazoan tissues and V. cholerae has been identified in association with invertebrate and vertebrate marine animals, as well as in a benthic zone of the ocean where organic matter, including collagens, accumulates. Here, we describe the characterization of the V. cholerae putative collagenase, VchC, encoded by open reading frame VC1650 and belonging to the subfamily M9A peptidases. Our studies demonstrate that VchC is an extracellular collagenase degrading native type I collagen of fish and mammalian origin. Alteration of the predicted catalytic residues coordinating zinc ions completely abolished the protein enzymatic activity but did not affect the translocation of the protease by the type II secretion pathway into the extracellular milieu. We also show that the protease undergoes a maturation process with the aid of a secreted factor(s). Finally, we propose that V. cholerae is a collagenovorous bacterium, as it is able to utilize collagen as a sole nutrient source. This study initiates new lines of investigations aiming to uncover the structural and functional components of the V. cholerae collagen utilization program. Members of the genus Vibrio are important inhabitants of the marine coastal waters, estuaries, and ocean sediments, with some pathogenic species also causing wound infections, primary septicemia, gastroenteritis, and diarrhea in humans (1, 2). Among the more than 200 serogroups of V. cholerae, only O1 and O139 are recognized as agents of cholera, a potentially life-threatening diarrheal disease. Cholera remains a significant public health problem by affecting millions of people annually, predominantly in developing countries that have limited clean water supplies and poor sanitation (3). Infection of the human host occurs upon ingestion of water or food contaminated with the bacterium. Following colonization of the small intestine, V. cholerae utilizes a multicomponent secretory pathway, the type II secretion system (T2SS), to release cholera toxin. Cholera toxin induces acute diarrhea in people infected with cholera, enabling the bacteria to escape from the host into the aquatic reservoir (4). During interepidemic periods, V. cholerae persists freely or in association with various aquatic organisms, including copepods, insect egg masses, shellfish, and vertebrate fish (5-7). Extracellular proteins, including those secreted by the T2SS, have been implicated in facilitating the fitness of V. cholerae in both the human host and aquatic niches (4,6,8). The array of extrace...

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“…However, a particularly interesting and recent finding is that one of the promoters driving expression of the epsC-N operon is RpoE-dependent. 79 One possible rationale for this control is to ensure increased T2SS production and virulence factor export when V. cholerae enters its host, where it encounters RpoE-inducing stimuli such as CAMPs and altered environmental conditions. An alternative rationale, suggested by removal of the T2SS compromising envelope integrity, is that increased production of the T2SS is an important component of the RpoEdependent envelope stress-reduction mechanism.…”

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confidence: 99%

Regulation of bacterial virulence gene expression by cell envelope stress responses

Flores-Kim

Darwin

2014

Virulence

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The Type II Secretion Pathway in Vibrio cholerae Is Characterized by Growth Phase-Dependent Expression of Exoprotein Genes and Is Positively Regulated by σ ^E

Cited by 22 publications

References 51 publications

Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

A Metalloprotease Secreted by the Type II Secretion System Links Vibrio cholerae with Collagen

Regulation of bacterial virulence gene expression by cell envelope stress responses

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The Type II Secretion Pathway in Vibrio cholerae Is Characterized by Growth Phase-Dependent Expression of Exoprotein Genes and Is Positively Regulated by σ E

Cited by 22 publications

References 51 publications

Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

Cyclic Di-GMP and VpsR Induce the Expression of Type II Secretion in Vibrio cholerae

A Metalloprotease Secreted by the Type II Secretion System Links Vibrio cholerae with Collagen

Regulation of bacterial virulence gene expression by cell envelope stress responses

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The Type II Secretion Pathway in Vibrio cholerae Is Characterized by Growth Phase-Dependent Expression of Exoprotein Genes and Is Positively Regulated by σ ^E