Secreted Proteases Control the Timing of Aggregative Community Formation in Vibrio cholerae

Bacteria can work as collectives to form multicellular communities. Vibrio cholerae , the bacterium that causes the disease cholera in humans, forms aggregated communities in liquid. Aggregate formation relies on a chemical communication process called quorum sensing.

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The Vibrio cholerae Quorum-Sensing Protein VqmA Integrates Cell Density, Environmental, and Host-Derived Cues into the Control of Virulence

mBio ◽

10.1128/mbio.01572-20 ◽

2020 ◽

Vol 11 (4) ◽

Author(s):

Ameya A. Mashruwala ◽

Bonnie L. Bassler

Keyword(s):

Small Intestine ◽

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

Chemical Communication ◽

Bile Salts ◽

Anaerobic Growth ◽

Signal Molecules ◽

Content Type ◽

Collective Behaviors

ABSTRACT Quorum sensing is a chemical communication process in which bacteria use the production, release, and detection of signal molecules called autoinducers to orchestrate collective behaviors. The human pathogen Vibrio cholerae requires quorum sensing to infect the small intestine. There, V. cholerae encounters the absence of oxygen and the presence of bile salts. We show that these two stimuli differentially affect quorum-sensing function and, in turn, V. cholerae pathogenicity. First, during anaerobic growth, V. cholerae does not produce the CAI-1 autoinducer, while it continues to produce the DPO autoinducer, suggesting that CAI-1 may encode information specific to the aerobic lifestyle of V. cholerae. Second, the quorum-sensing receptor-transcription factor called VqmA, which detects the DPO autoinducer, also detects the lack of oxygen and the presence of bile salts. Detection occurs via oxygen-, bile salt-, and redox-responsive disulfide bonds that alter VqmA DNA binding activity. We propose that VqmA serves as an information processing hub that integrates quorum-sensing information, redox status, the presence or absence of oxygen, and host cues. In response to the information acquired through this mechanism, V. cholerae appropriately modulates its virulence output. IMPORTANCE Quorum sensing (QS) is a process of chemical communication that bacteria use to orchestrate collective behaviors. QS communication relies on chemical signal molecules called autoinducers. QS regulates virulence in Vibrio cholerae, the causative agent of the disease cholera. Transit into the human small intestine, the site of cholera infection, exposes V. cholerae to the host environment. In this study, we show that the combination of two stimuli encountered in the small intestine, the absence of oxygen and the presence of host-produced bile salts, impinge on V. cholerae QS function and, in turn, pathogenicity. We suggest that possessing a QS system that is responsive to multiple environmental, host, and cell density cues enables V. cholerae to fine-tune its virulence capacity in the human intestine.

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Secreted Proteases Control the Timing of Aggregative Community Formation in Vibrio cholerae

10.1101/2021.05.25.445717 ◽

2021 ◽

Author(s):

Matthew Jemielita ◽

Ameya A Mashruwala ◽

Julie S Valastyan ◽

Ned Wingreen ◽

Bonnie Bassler

Keyword(s):

Small Molecules ◽

Vibrio Cholerae ◽

Void Formation ◽

Cell Communication ◽

Communication Process ◽

Community Formation ◽

Extracellular Proteases ◽

Collective Behaviors ◽

Onset Timing ◽

Secreted Proteases

Bacteria orchestrate collective behaviors using the cell-cell communication process called quorum sensing (QS). QS relies on the synthesis, release, and group-wide detection of small molecules called autoinducers. In Vibrio cholerae, a multicellular community aggregation program occurs in liquid, during stationary phase, and in the high-cell-density QS state. Here, we demonstrate that this aggregation program consists of two subprograms. In one subprogram, which we call void formation, structures form that contain few cells but provide a scaffold within which cells can embed. The other subprogram relies on flagellar machinery and enables cells to enter voids. A genetic screen for factors contributing to void formation, coupled with companion molecular analyses, showed that four extracellular proteases, Vca0812, Vca0813, HapA, and PrtV control the onset timing of both void formation and aggregation, and moreover, proteolytic activity is required. These proteases, or their downstream products, can be shared between void-producing and non-void-forming cells and can elicit aggregation in a normally non-aggregating V. cholerae strain. Employing multiple proteases to control void formation and aggregation timing could provide a redundant and irreversible path to commitment to this community lifestyle.

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The Vibrio cholerae quorum-sensing protein VqmA integrates cell density, environmental, and host-derived cues into the control of virulence

10.1101/2020.05.04.076810 ◽

2020 ◽

Cited By ~ 1

Author(s):

Ameya A. Mashruwala ◽

Bonnie L. Bassler

Keyword(s):

Small Intestine ◽

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

Chemical Communication ◽

Disulfide Bonds ◽

Redox Status ◽

Communication Process ◽

Signal Molecules ◽

Collective Behaviors

Scientific AbstractQuorum sensing is a chemical communication process in which bacteria use the production, release, and detection of signal molecules called autoinducers to orchestrate collective behaviors. The human pathogen Vibrio cholerae requires quorum sensing to infect the small intestine. There, V. cholerae encounters the absence of oxygen and the presence of bile. We show that these two stimuli differentially affect quorum sensing function and, in turn, V. cholerae pathogenicity. The quorum-sensing receptor-transcription factor called VqmA, that detects the autoinducer called DPO, also detects the lack of oxygen and the presence of bile. Detection occurs via DPO-, oxygen-, bile-, and redox-responsive disulfide bonds that alter VqmA DNA binding activity. We propose that VqmA serves as an information processing hub that integrates quorum- sensing information, redox status, the presence or absence of oxygen, and host cues. In response to the information acquired through this mechanism, V. cholerae appropriately modulates its virulence output.Lay AbstractQuorum sensing (QS) is a process of chemical communication bacteria use to orchestrate collective behaviors. QS communication relies on chemical signal molecules called autoinducers. QS regulates virulence in Vibrio cholerae, the causative agent of the disease cholera. Transit into the human small intestine, the site of cholera infection, exposes V. cholerae to the host environment. In this study, we show that the combination of two stimuli encountered in the small intestine, the absence of oxygen and the presence of host-produced bile, impinge on V. cholerae QS function and, in turn, pathogenicity. We suggest that possessing a QS system that is responsive to multiple environmental, host, and cell density cues enables V. cholerae to fine-tune its virulence capacity in the human intestine.

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Integration of Cyclic di-GMP and Quorum Sensing in the Control ofvpsTandaphAin Vibrio cholerae

Journal of Bacteriology ◽

10.1128/jb.05167-11 ◽

2011 ◽

Vol 193 (22) ◽

pp. 6331-6341 ◽

Cited By ~ 103

Author(s):

Disha Srivastava ◽

Rebecca C. Harris ◽

Christopher M. Waters

Keyword(s):

Quorum Sensing ◽

Binding Site ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Virulence Gene ◽

Transcriptional Activator ◽

Transcriptional Regulators ◽

Content Type ◽

Virulence Gene Expression ◽

Signaling Systems

Vibrio choleraetransitions between aquatic environmental reservoirs and infection in the gastrointestinal tracts of human hosts. The second-messenger molecule cyclic di-GMP (c-di-GMP) and quorum sensing (QS) are important signaling systems that enableV. choleraeto alternate between these distinct environments by controlling biofilm formation and virulence factor expression. Here we identify a conserved regulatory mechanism inV. choleraethat integrates c-di-GMP and QS to control the expression of two transcriptional regulators:aphA, an activator of virulence gene expression and an important regulator of the quorum-sensing pathway, andvpsT, a transcriptional activator that induces biofilm formation. Surprisingly,aphAexpression was induced by c-di-GMP. Activation of bothaphAandvpsTby c-di-GMP requires the transcriptional activator VpsR, which binds to c-di-GMP. The VpsR binding site at each of these promoters overlaps with the binding site of HapR, the master QS regulator at high cell densities. Our results suggest thatV. choleraecombines information conveyed by QS and c-di-GMP to appropriately respond and adapt to divergent environments by modulating the expression of key transcriptional regulators.

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Mechanism underlying the DNA-binding preferences of the Vibrio cholerae and vibriophage VP882 VqmA quorum-sensing receptors

10.1101/2021.04.15.439952 ◽

2021 ◽

Author(s):

Bonnie L. Bassler ◽

Olivia Duddy ◽

Xiuliang Huang ◽

Justin Silpe

Keyword(s):

Dna Binding ◽

Quorum Sensing ◽

Vibrio Cholerae ◽

Dna Sequences ◽

Genetic Screen ◽

Binding Domain ◽

Communication Process ◽

Dna Binding Domain ◽

Phage Gene ◽

Small Regulatory Rna

Quorum sensing is a chemical communication process that bacteria use to coordinate group behaviors. In the global pathogen Vibrio cholerae, one quorum-sensing receptor and transcription factor, called VqmA (VqmAVc), activates expression of the vqmR gene encoding the small regulatory RNA VqmR, which represses genes involved in virulence and biofilm formation. Vibriophage VP882 encodes a VqmA homolog called VqmAPhage that activates transcription of the phage gene qtip, and Qtip launches the phage lytic program. Curiously, VqmAPhage can activate vqmR expression but VqmAVc cannot activate expression of qtip. Here, we investigate the mechanism underlying this asymmetry. We find that promoter selectivity is driven exclusively by each VqmA DNA-binding domain and key DNA sequences in the vqmR and qtip promoters are required to maintain specificity. A protein sequence-guided mutagenesis approach revealed that the residue E194 of VqmAPhage and A192, the equivalent residue in VqmAVc, in the helix-turn-helix motifs contribute to promoter-binding specificity. A genetic screen to identify VqmAPhage mutants that are incapable of binding the qtip promoter but maintain binding to the vqmR promoter delivered additional VqmAPhage residues located immediately C-terminal to the helix-turn-helix motif as required for binding the qtip promoter. Surprisingly, these residues are conserved between VqmAPhage and VqmAVc. A second, targeted genetic screen revealed a region located in the VqmAVc DNA-binding domain as necessary to prevent VqmAVc from binding the qtip promoter, thus restricting DNA-binding to the vqmR promoter. We propose that the VqmAVc helix-turn-helix motif and the C-terminal flanking residues function together to prohibit VqmAVc from binding the qtip promoter.

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Saccharomyces cerevisiae Requires CFF1 To Produce 4-Hydroxy-5-Methylfuran-3(2H)-One, a Mimic of the Bacterial Quorum-Sensing Autoinducer AI-2

mBio ◽

10.1128/mbio.03303-20 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Julie S. Valastyan ◽

Christina M. Kraml ◽

Istvan Pelczer ◽

Thomas Ferrante ◽

Bonnie L. Bassler

Keyword(s):

Saccharomyces Cerevisiae ◽

Quorum Sensing ◽

Bacterial Species ◽

Cell Communication ◽

Communication Process ◽

Signal Molecules ◽

Catalytic Residue ◽

Interspecies Communication ◽

Content Type ◽

Extracellular Signal

ABSTRACT Quorum sensing is a process of cell-to-cell communication that bacteria use to orchestrate collective behaviors. Quorum sensing depends on the production, release, and detection of extracellular signal molecules called autoinducers (AIs) that accumulate with increasing cell density. While most AIs are species specific, the AI called AI-2 is produced and detected by diverse bacterial species, and it mediates interspecies communication. We recently reported that mammalian cells produce an AI-2 mimic that can be detected by bacteria through the AI-2 receptor LuxP, potentially expanding the role of the AI-2 system to interdomain communication. Here, we describe a second molecule capable of interdomain signaling through LuxP, 4-hydroxy-5-methylfuran-3(2H)-one (MHF), that is produced by the yeast Saccharomyces cerevisiae. Screening the S. cerevisiae deletion collection revealed Cff1p, a protein with no known role, to be required for MHF production. Cff1p is proposed to be an enzyme, with structural similarity to sugar isomerases and epimerases, and substitution at the putative catalytic residue eliminated MHF production in S. cerevisiae. Sequence analysis uncovered Cff1p homologs in many species, primarily bacterial and fungal, but also viral, archaeal, and higher eukaryotic. Cff1p homologs from organisms from all domains can complement a cff1Δ S. cerevisiae mutant and restore MHF production. In all cases tested, the identified catalytic residue is conserved and required for MHF to be produced. These findings increase the scope of possibilities for interdomain interactions via AI-2 and AI-2 mimics, highlighting the breadth of molecules and organisms that could participate in quorum sensing. IMPORTANCE Quorum sensing is a cell-to-cell communication process that bacteria use to monitor local population density. Quorum sensing relies on extracellular signal molecules called autoinducers (AIs). One AI called AI-2 is broadly made by bacteria and used for interspecies communication. Here, we describe a eukaryotic AI-2 mimic, 4-hydroxy-5-methylfuran-3(2H)-one, (MHF), that is made by the yeast Saccharomyces cerevisiae, and we identify the Cff1p protein as essential for MHF production. Hundreds of viral, archaeal, bacterial, and eukaryotic organisms possess Cff1p homologs. This finding, combined with our results showing that homologs from all domains can replace S. cerevisiae Cff1p, suggests that like AI-2, MHF is widely produced. Our results expand the breadth of organisms that may participate in quorum-sensing-mediated interactions.

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Levels of the Secreted Vibrio cholerae Attachment Factor GbpA Are Modulated by Quorum-Sensing-Induced Proteolysis

Journal of Bacteriology ◽

10.1128/jb.00747-09 ◽

2009 ◽

Vol 191 (22) ◽

pp. 6911-6917 ◽

Cited By ~ 34

Author(s):

Brooke A. Jude ◽

Raquel M. Martinez ◽

Karen Skorupski ◽

Ronald K. Taylor

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

Protein A ◽

Etiologic Agent ◽

Expression Of Genes ◽

Genes Encoding ◽

Secreted Proteases ◽

Low Cell Density ◽

Attachment Factor

ABSTRACT Vibrio cholerae is the etiologic agent of cholera in humans. Intestinal colonization occurs in a stepwise fashion, initiating with attachment to the small intestinal epithelium. This attachment is followed by expression of the toxin-coregulated pilus, microcolony formation, and cholera toxin (CT) production. We have recently characterized a secreted attachment factor, GlcNAc binding protein A (GbpA), which functions in attachment to environmental chitin sources as well as to intestinal substrates. Studies have been initiated to define the regulatory network involved in GbpA induction. At low cell density, GbpA was detected in the culture supernatant of all wild-type (WT) strains examined. In contrast, at high cell density, GbpA was undetectable in strains that produce HapR, the central regulator of the cell density-dependent quorum-sensing system of V. cholerae. HapR represses the expression of genes encoding regulators involved in V. cholerae virulence and activates the expression of genes encoding the secreted proteases HapA and PrtV. We show here that GbpA is degraded by HapA and PrtV in a time-dependent fashion. Consistent with this, ΔhapA ΔprtV strains attach to chitin beads more efficiently than either the WT or a ΔhapA ΔprtV ΔgbpA strain. These results suggest a model in which GbpA levels fluctuate in concert with the bacterial production of proteases in response to quorum-sensing signals. This could provide a mechanism for GbpA-mediated attachment to, and detachment from, surfaces in response to environmental cues.

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Ethanolamine regulates CqsR quorum-sensing signaling inVibrio cholerae

10.1101/589390 ◽

2019 ◽

Cited By ~ 3

Author(s):

Samit Watve ◽

Kelsey Barrasso ◽

Sarah A. Jung ◽

Kristen J. Davis ◽

Lisa A. Hawver ◽

...

Keyword(s):

Gene Expression ◽

Quorum Sensing ◽

Vibrio Cholerae ◽

Cell Density ◽

High Cell Density ◽

Chemical Signals ◽

Communication Process ◽

Control Group ◽

Dual Function ◽

High Cell

ABSTRACTThe pathogen that causes cholera,Vibrio cholerae, uses the cell-cell communication process known as quorum sensing (QS) to regulate virulence factor production and biofilm formation in response to changes in population density and complexity. QS is mediated through the detection of extracellular chemical signals called autoinducers. Four histidine kinases, LuxPQ, CqsS, CqsR and VpsS, have been identified as receptors to activate the key QS regulator LuxO at low cell density. At high cell density, detection of autoinducers by these receptors leads to deactivation of LuxO, resulting in population-wide gene expression changes. While the cognate autoinducers that regulate the activity of CqsS and LuxQ are known, the signals that regulate CqsR have not been determined. Here we show that the common metabolite ethanolamine specifically interacts with the ligand-binding CACHE domain of CqsRin vitroand induces the high cell-density QS response through CqsR kinase inhibition inV. choleraecells. We also identified residues in the CqsR CACHE domain important for ethanolamine detection and signal transduction. Moreover, mutations disrupting endogenous ethanolamine production inV. choleraedelay the onset of, but do not abolish, the high cell-density QS gene expression. Finally, we demonstrate that modulation of CqsR QS response by ethanolamine occurs inside animal hosts. Our findings suggest thatV. choleraeuses CqsR as a dual-function receptor to integrate information from the self-made signals as well as exogenous ethanolamine as an environmental cue to modulate QS response.IMPORTANCEMany bacteria use quorum sensing to regulate cellular processes that are important for their survival and adaptation to different environments. Quorum sensing usually depends on the detection on chemical signals called autoinducers made endogenously by the bacteria. We show here ethanolamine, a common metabolite made by various bacteria and eukaryotes, can modulate the activity of one of the quorum-sensing receptors inVibrio cholerae, the etiological agent of the disease cholera. Our results raise the possibility thatV. choleraeor other quorum-sensing bacteria can combine environmental sensing and quorum sensing to control group behaviors.

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Mechanism underlying autoinducer recognition in the Vibrio cholerae DPO-VqmA quorum-sensing pathway

10.1101/2019.12.19.881847 ◽

2019 ◽

Author(s):

Xiuliang Huang ◽

Olivia P. Duddy ◽

Justin E. Silpe ◽

Jon E. Paczkowski ◽

Jianping Cong ◽

...

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Conformational Changes ◽

Site Directed Mutagenesis ◽

Communication Process ◽

Linear Molecule ◽

Gene Encoding ◽

Collective Behaviors ◽

Existing Structures ◽

Extracellular Signaling

ABSTRACTQuorum sensing is a bacterial communication process whereby bacteria produce, release and detect the accumulation of extracellular signaling molecules called autoinducers to coordinate collective behaviors. In Vibrio cholerae, the quorum-sensing autoinducer, DPO (3,5-dimethyl-pyrazin-2-ol), binds the receptor-transcription factor, VqmA. In response, the DPO-VqmA complex activates transcription of the vqmR gene encoding the VqmR small RNA. VqmR represses genes required for biofilm formation and virulence factor production. Here, we show that VqmA has DPO-dependent and DPO-independent activity. We solved the DPO-VqmA crystal structure and compared it to existing structures to understand the conformational changes the protein undergoes upon DNA binding. Analysis of DPO analogs reveals that a hydroxyl or carbonyl group at the 2’ position is critical for binding. The proposed DPO precursor, a linear molecule, Ala-AA (N-alanyl-aminoacetone), also binds and activates VqmA. DPO and Ala-AA occupy the same binding site as judged by site-directed mutagenesis and competitive ligand binding analyses.

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Quorum sensing controls Vibrio cholerae multicellular aggregate formation

eLife ◽

10.7554/elife.42057 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 16

Author(s):

Matthew Jemielita ◽

Ned S Wingreen ◽

Bonnie L Bassler

Keyword(s):

Quorum Sensing ◽

Vibrio Cholerae ◽

Biofilm Formation ◽

Aggregate Size ◽

Extracellular Dna ◽

Signal Molecules ◽

Aggregate Formation ◽

Multicellular Aggregate ◽

Canonical Surface ◽

Pandemic Strains

Bacteria communicate and collectively regulate gene expression using a process called quorum sensing (QS). QS relies on group-wide responses to signal molecules called autoinducers. Here, we show that QS activates a new program of multicellularity in Vibrio cholerae. This program, which we term aggregation, is distinct from the canonical surface-biofilm formation program, which QS represses. Aggregation is induced by autoinducers, occurs rapidly in cell suspensions, and does not require cell division, features strikingly dissimilar from those characteristic of V. cholerae biofilm formation. Extracellular DNA limits aggregate size, but is not sufficient to drive aggregation. A mutagenesis screen identifies genes required for aggregate formation, revealing proteins involved in V. cholerae intestinal colonization, stress response, and a protein that distinguishes the current V. cholerae pandemic strain from earlier pandemic strains. We suggest that QS-controlled aggregate formation is important for V. cholerae to successfully transit between the marine niche and the human host.

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