Faculty Opinions recommendation of FimX, a multidomain protein connecting environmental signals to twitching motility in Pseudomonas aeruginosa.

2004 ◽  
Author(s):  
Fergal O'Gara
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Twitching Motility ◽  
Environmental Signals ◽  
Multidomain Protein

scholarly journals ChpC controls twitching motility-mediated expansion of Pseudomonas aeruginosa biofilms in response to serum albumin, mucin and oligopeptides

2019 ◽  
Author(s):  
Laura M. Nolan ◽  
Laura C. McCaughey ◽  
Jessica Merjane ◽  
Lynne Turnbull ◽  
Cynthia B. Whitchurch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Serum Albumin ◽  
Histidine Kinase ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Adapter Proteins ◽  
Twitching Motility ◽  
Chemosensory System ◽  
Environmental Signals ◽  
Chp System

AbstractTwitching motility-mediated biofilm expansion occurs via coordinated, multi-cellular collective behaviour to allow bacteria to actively expand across surfaces. Type-IV pili (T4P) are cell-associated virulence factors which mediate this expansion via rounds of extension, surface attachment and retraction. The Chp chemosensory system is thought to respond to environmental signals to regulate the biogenesis, assembly and twitching motility function of T4P. In other well characterised chemosensory systems, methyl-accepting chemotaxis proteins (MCPs) feed environmental signals through a CheW adapter protein to the histidine kinase CheA to modulate motility. The Pseudomonas aeruginosa Chp system has two CheW adapter proteins, PilI and ChpC, and an MCP PilJ that likely interacts via PilI with the histidine kinase ChpA. It is thought that ChpC associates with other MCPs to feed environmental signals into the system, however no such signals have been identified. In the current study we show that ChpC is involved in the response to host-derived signals serum albumin, mucin and oligopeptides. We demonstrate that these signals stimulate an increase in twitching motility, as well as in levels of 3’-5’-cyclic adenosine monophosphate (cAMP) and surface-assembled T4P. Interestingly, our data shows that changes in cAMP and surface piliation levels are independent of ChpC but that the twitching motility response to these environmental signals requires ChpC. Based upon our data we propose a model whereby ChpC associates with an MCP other than PilJ to feed these environmental signals through the Chp system to control twitching motility. The MCP PilJ and the CheW adapter PilI then modulate T4P surface levels to allow the cell to continue to undergo twitching motility. Our study is the first to link environmental signals to the Chp chemosensory system and refines our understanding of how this system controls twitching motility-mediated biofilm expansion in P. aeruginosa.

scholarly journals ChpC controls twitching motility-mediated expansion of Pseudomonas aeruginosa biofilms in response to serum albumin, mucin and oligopeptides

Microbiology ◽  
2020 ◽  
Vol 166 (7) ◽  
pp. 669-678
Author(s):  
Laura M. Nolan ◽  
Laura C. McCaughey ◽  
Jessica Merjane ◽  
Lynne Turnbull ◽  
Cynthia B. Whitchurch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Serum Albumin ◽  
Histidine Kinase ◽  
Type Species ◽  
Twitching Motility ◽  
Chemosensory System ◽  
Content Type ◽  
Environmental Signals ◽  
Link Type ◽  
Chp System

Twitching motility-mediated biofilm expansion occurs via coordinated, multi-cellular collective behaviour to allow bacteria to actively expand across surfaces. Type-IV pili (T4P) are cell-associated virulence factors which mediate twitching motility via rounds of extension, surface attachment and retraction. The Chp chemosensory system is thought to respond to environmental signals to regulate the biogenesis, assembly and twitching motility function of T4P. In other well characterised chemosensory systems, methyl-accepting chemotaxis proteins (MCPs) feed environmental signals through a CheW adapter protein to the histidine kinase CheA to modulate motility. The Pseudomonas aeruginosa Chp system has an MCP PilJ and two CheW adapter proteins, PilI and ChpC, that likely interact with the histidine kinase ChpA to feed environmental signals into the system. In the current study we show that ChpC is involved in the response to host-derived signals serum albumin, mucin and oligopeptides. We demonstrate that these signals stimulate an increase in twitching motility, as well as in levels of 3′−5′-cyclic adenosine monophosphate (cAMP) and surface-assembled T4P. Interestingly, our data shows that changes in cAMP and surface piliation levels are independent of ChpC but that the twitching motility response to these environmental signals requires ChpC. Furthermore, we show that protease activity is required for the twitching motility response of P. aeruginosa to environmental signals. Based upon our data we propose a model whereby ChpC feeds these environmental signals into the Chp system, potentially via PilJ or another MCP, to control twitching motility. PilJ and PilI then modulate T4P surface levels to allow the cell to continue to undergo twitching motility. Our study is the first to link environmental signals to the Chp chemosensory system and refines our understanding of how this system controls twitching motility-mediated biofilm expansion in P. aeruginosa .

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

scholarly journals Disparate Subcellular Localization Patterns of Pseudomonas aeruginosa Type IV Pilus ATPases Involved in Twitching Motility

2005 ◽  
Vol 187 (3) ◽  
pp. 829-839 ◽  
Author(s):  
Poney Chiang ◽  
Marc Habash ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Protein ◽  
Protein Localization ◽  
Yellow Fluorescent Protein ◽  
Distribution Patterns ◽  
Opportunistic Pathogen ◽  
Twitching Motility ◽  
Polar Localization ◽  
Type Iv ◽  
And Function

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa expresses polar type IV pili (TFP), which are responsible for adhesion to various materials and twitching motility on surfaces. Twitching occurs by alternate extension and retraction of TFP, which arise from assembly and disassembly of pilin subunits at the base of the pilus. The ATPase PilB promotes pilin assembly, while the ATPase PilT or PilU or both promote pilin dissociation. Fluorescent fusions to two of the three ATPases (PilT and PilU) were functional, as shown by complementation of the corresponding mutants. PilB and PilT fusions localized to both poles, while PilU fusions localized only to the piliated pole. To identify the portion of the ATPases required for localization, sequential C-terminal deletions of PilT and PilU were generated. The conserved His and Walker B boxes were dispensable for polar localization but were required for twitching motility, showing that localization and function could be uncoupled. Truncated fusions that retained polar localization maintained their distinctive distribution patterns. To dissect the cellular factors involved in establishing polarity, fusion protein localization was monitored with a panel of TFP mutants. The localization of yellow fluorescent protein (YFP)-PilT and YFP-PilU was independent of the subunit PilA, other TFP ATPases, and TFP-associated proteins previously shown to be associated with the membrane or exhibiting polar localization. In contrast, YFP-PilB exhibited diffuse cytoplasmic localization in a pilC mutant, suggesting that PilC is required for polar localization of PilB. Finally, localization studies performed with fluorescent ATPase chimeras of PilT and PilU demonstrated that information responsible for the characteristic localization patterns of the ATPases likely resides in their N termini.

scholarly journals Single-Residue Changes in the C-Terminal Disulfide-Bonded Loop of the Pseudomonas aeruginosa Type IV Pilin Influence Pilus Assembly and Twitching Motility

2009 ◽  
Vol 191 (21) ◽  
pp. 6513-6524 ◽  
Author(s):  
Hanjeong Harvey ◽  
Marc Habash ◽  
Francisca Aidoo ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antigenic Variation ◽  
Intact Protein ◽  
Twitching Motility ◽  
Beta Turn ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Intersubunit Interactions ◽  
Pilus Assembly

ABSTRACT PilA, the major pilin subunit of Pseudomonas aeruginosa type IV pili (T4P), is a principal structural component. PilA has a conserved C-terminal disulfide-bonded loop (DSL) that has been implicated as the pilus adhesinotope. Structural studies have suggested that DSL is involved in intersubunit interactions within the pilus fiber. PilA mutants with single-residue substitutions, insertions, or deletions in the DSL were tested for pilin stability, pilus assembly, and T4P function. Mutation of either Cys residue of the DSL resulted in pilins that were unable to assemble into fibers. Ala replacements of the intervening residues had a range of effects on assembly or function, as measured by changes in surface pilus expression and twitching motility. Modification of the C-terminal P-X-X-C type II beta-turn motif, which is one of the few highly conserved features in pilins across various species, caused profound defects in assembly and twitching motility. Expression of pilins with suspected assembly defects in a pilA pilT double mutant unable to retract T4P allowed us to verify which subunits were physically unable to assemble. Use of two different PilA antibodies showed that the DSL may be an immunodominant epitope in intact pili compared with pilin monomers. Sequence diversity of the type IVa pilins likely reflects an evolutionary compromise between retention of function and antigenic variation. The consequences of DSL sequence changes should be evaluated in the intact protein since it is technically feasible to generate DSL-mimetic peptides with mutations that will not appear in the natural repertoire due to their deleterious effects on assembly.

scholarly journals Bicarbonate Evokes Reciprocal Changes in Intracellular Cyclic di-GMP and Cyclic AMP Levels in Pseudomonas aeruginosa

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 519
Author(s):  
Kasidid Ruksakiet ◽  
Balázs Stercz ◽  
Gergő Tóth ◽  
Pongsiri Jaikumpun ◽  
Ilona Gróf ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cyclic Amp ◽  
Biofilm Formation ◽  
Second Messengers ◽  
Brain Heart Infusion ◽  
Ambient Air ◽  
Dependent Manner ◽  
Environmental Signals ◽  
Common Causes ◽  
Camp Levels

The formation of Pseudomonas aeruginosa biofilms in cystic fibrosis (CF) is one of the most common causes of morbidity and mortality in CF patients. Cyclic di-GMP and cyclic AMP are second messengers regulating the bacterial lifestyle transition in response to environmental signals. We aimed to investigate the effects of extracellular pH and bicarbonate on intracellular c-di-GMP and cAMP levels, and on biofilm formation. P. aeruginosa was inoculated in a brain–heart infusion medium supplemented with 25 and 50 mM NaCl in ambient air (pH adjusted to 7.4 and 7.7 respectively), or with 25 and 50 mM NaHCO3 in 5% CO2 (pH 7.4 and 7.7). After 16 h incubation, c-di-GMP and cAMP were extracted and their concentrations determined. Biofilm formation was investigated using an xCelligence real-time cell analyzer and by crystal violet assay. Our results show that HCO3− exposure decreased c-di-GMP and increased cAMP levels in a dose-dependent manner. Biofilm formation was also reduced after 48 h exposure to HCO3−. The reciprocal changes in second messenger concentrations were not influenced by changes in medium pH or osmolality. These findings indicate that HCO3− per se modulates the levels of c-di-GMP and cAMP, thereby inhibiting biofilm formation and promoting the planktonic lifestyle of the bacteria.

Characterization of a complex chemosensory signal transduction system which controls twitching motility in Pseudomonas aeruginosa

2004 ◽  
Vol 52 (3) ◽  
pp. 873-893 ◽  
Author(s):  
Cynthia B. Whitchurch ◽  
Andrew J. Leech ◽  
Michael D. Young ◽  
Derek Kennedy ◽  
Jennifer L. Sargent ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Pseudomonas Aeruginosa ◽  
Twitching Motility ◽  
Signal Transduction System

scholarly journals BdlA, a Chemotaxis Regulator Essential for Biofilm Dispersion in Pseudomonas aeruginosa

2006 ◽  
Vol 188 (21) ◽  
pp. 7335-7343 ◽  
Author(s):  
Ryan Morgan ◽  
Steven Kohn ◽  
Sung-Hei Hwang ◽  
Daniel J. Hassett ◽  
Karin Sauer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gene Product ◽  
Signaling Cascade ◽  
Environmental Cues ◽  
Environmental Sensing ◽  
Environmental Signals ◽  
Isogenic Mutant ◽  
Biofilm Detachment ◽  
Biofilm Dispersion ◽  
Do So

ABSTRACT Multiple environmental cues have been shown to trigger biofilm detachment, the transition from surface-attached, highly organized communities known as biofilms to the motile lifestyle. The goal of this study was to identify a gene product involved in sensing environmental cues that trigger biofilm dispersion in Pseudomonas aeruginosa. To do so, we focused on novel putative chemotaxis transducer proteins that could potentially be involved in environmental sensing. We identified a locus encoding such a protein that played a role in detachment, as indicated by the observation that an isogenic mutant biofilm could not disperse in response to a variety of environmental cues. The locus was termed bdlA for biofilm dispersion locus. The BdlA protein harbors an MCP (methyl-accepting chemotaxis protein) domain and two PAS (Per-Arnt-Sint) domains that have been shown to be essential for responding to environmental signals in other proteins. The dispersion-deficient phenotype of the bdlA mutant was confirmed by treatment with the biocide H2O2 and by microscopic observations. The dispersion response was independent of motility. bdlA mutant biofilms were found to have increased adherent properties and increased intracellular levels of cyclic di-GMP (c-di-GMP). Our findings suggest that BdlA may be a link between sensing environmental cues, c-di-GMP levels, and detachment. Based on our findings, a possible involvement of BdlA in a signaling cascade resulting in biofilm dispersion is discussed.

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