Extragenic suppressor mutations that restore twitching motility to <scp><i>fimL</i></scp> mutants of <i><scp>P</scp>seudomonas aeruginosa</i> are associated with elevated intracellular cyclic <scp>AMP</scp> levels

Nolan, Laura M.; Beatson, Scott A.; Croft, Larry; Jones, Peter M.; George, Anthony M.; Mattick, John S.; Turnbull, Lynne; Whitchurch, Cynthia B.

doi:10.1002/mbo3.49

Cited by 13 publications

(15 citation statements)

References 36 publications

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“…Notably, CpdA homologs of V. cholerae [56] and P. aeruginosa are required for colonization efficiency and regulation of twitching-motility and virulence factors [53], [57], [58], respectively. The stringent control of cAMP levels is important in a wide variety of bacterial behaviors, thus we hypothesized that cAMP-PDEs could have an uncharacterized role in mediating other pathogenesis-associated phenotypes.…”

Section: Discussionmentioning

confidence: 99%

Bacterial Cyclic AMP-Phosphodiesterase Activity Coordinates Biofilm Formation

et al. 2013

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Biofilm-related infections are a major contributor to human disease, and the capacity for surface attachment and biofilm formation are key attributes for the pathogenesis of microbes. Serratia marcescens type I fimbriae-dependent biofilms are coordinated by the adenylate cyclase, CyaA, and the cyclic 3′,5′-adenosine monophosphate (cAMP)-cAMP receptor protein (CRP) complex. This study uses S. marcescens as a model system to test the role of cAMP-phosphodiesterase activity in controlling biofilm formation. Herein we describe the characterization of a putative S. marcescens cAMP-phosphodiesterase gene (SMA3506), designated as cpdS, and demonstrated to be a functional cAMP-phosphodiesterase both in vitro and in vivo. Deletion of cpdS resulted in defective biofilm formation and reduced type I fimbriae production, whereas multicopy expression of cpdS conferred a type I fimbriae-dependent hyper-biofilm. Together, these results support a model in which bacterial cAMP-phosphodiesterase activity modulates biofilm formation.

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Section: Discussionmentioning

confidence: 99%

Bacterial Cyclic AMP-Phosphodiesterase Activity Coordinates Biofilm Formation

et al. 2013

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“…FimL, FimV, and PilG are all required for activation of CyaB, with FimL proposed to link FimV to the Chp system through PilG (17,22,32,33). However, while phenotypes associated with fimL deletion could be rescued by deletion of cpdA or by increasing intracellular cAMP levels in other ways (22,33,34), provision of exogenous cAMP failed to restore motility to a pilG mutant (17). We investigated whether the cAMP-independent function of PilG also required FimV by comparing PilU levels-a proxy for intracellular cAMP levels (21, 25)-twitching, and piliation in fimL, fimV, and pilG single mutants or in double mutants also lacking cpdA to prevent the degradation of endogenous cAMP (33) (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, FimL's role in twitching is limited to its ability to connect PilG and FimV, leading to CyaB activation via an as-yet-unknown mechanism. Interestingly, Nolan et al (34) identified other suppressors of fimL that mapped outside the cyaA, cyaB, pilG, pilH, vfr, and cpdA loci. How those uncharacterized loci fit into the FimV-FimL-PilG signaling axis remains to be determined.…”

Section: Resultsmentioning

confidence: 99%

Cyclic AMP-Independent Control of Twitching Motility in Pseudomonas aeruginosa

et al. 2017

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FimV is a Pseudomonas aeruginosa inner membrane hub protein that modulates levels of the second messenger, cyclic AMP (cAMP), through the activation of adenylate cyclase CyaB. Although type IVa pilus (T4aP)-dependent twitching motility is modulated by cAMP levels, mutants lacking FimV are twitching impaired, even when exogenous cAMP is provided. Here we further define FimV's cAMPdependent and -independent regulation of twitching. We confirmed that the response regulator of the T4aP-associated Chp chemotaxis system, PilG, requires both FimV and the CyaB regulator, FimL, to activate CyaB. However, in cAMP-replete backgrounds-lacking the cAMP phosphodiesterase CpdA or the CheY-like protein PilH or expressing constitutively active CyaB-pilG and fimV mutants failed to twitch. Both cytoplasmic and periplasmic domains of FimV were important for its cAMPdependent and -independent roles, while its septal peptidoglycan-targeting LysM motif was required only for twitching motility. Polar localization of the sensor kinase PilS, a key regulator of transcription of the major pilin, was FimV dependent. However, unlike its homologues in other species that localize flagellar system components, FimV was not required for swimming motility. These data provide further evidence to support FimV's role as a key hub protein that coordinates the polar localization and function of multiple structural and regulatory proteins involved in P. aeruginosa twitching motility.IMPORTANCE Pseudomonas aeruginosa is a serious opportunistic pathogen. Type IVa pili (T4aP) are important for its virulence, because they mediate dissemination and invasion via twitching motility and are involved in surface sensing, which modulates pathogenicity via changes in cAMP levels. Here we show that the hub protein FimV and the response regulator of the Chp system, PilG, regulate twitching independently of their roles in the modulation of cAMP synthesis. These functions do not require the putative scaffold protein FimL, proposed to link PilG with FimV. PilG may regulate asymmetric functioning of the T4aP system to allow for directional movement, while FimV appears to localize both structural and regulatory elements-including the PilSR two-component system-to cell poles for optimal function.

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“…FimL, FimV, and PilG are all required for activation of CyaB, with FimL proposed to link FimV to the Chp system through PilG (17, 22, 31, 32). However, while phenotypes associated with fimL deletion could be rescued by deletion of cpdA or by increasing intracellular cAMP levels in other ways (22, 32, 33), provision of exogenous cAMP failed to restore motility in a pilG mutant (17). We investigated whether the cAMP-independent function of PilG also required FimV by comparing PilU levels – a proxy for intracellular cAMP levels (21, 25) – twitching, and piliation in fimL , fimV , and pilG single mutants or in double mutants also lacking cpdA to prevent degradation of endogenous cAMP (32) (Figure 1).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, FimL's role in twitching is limited to its ability to connect PilG and FimV, leading to CyaB activation via an as-yet unknown mechanism. Interestingly, Nolan et al (33) identified other suppressors of fimL that mapped outside the cyaA , cyaB , pilG , pilH , vfr , and cpdA loci. How those uncharacterized loci fit into the FimV-FimL-PilG signalling axis remains to be determined.…”

Section: Discussionmentioning

confidence: 99%

cAMP-independent control of twitching motility inPseudomonas aeruginosa

Buensuceso

Daniel-Ivad

Kilmury

et al. 2017

Preprint

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FimV is a Pseudomonas aeruginosa inner membrane hub protein that modulates levels of the second messenger, cyclic AMP (cAMP), through activation of the adenylate cyclase, CyaB. Although type IVa pilus (T4aP)-dependent twitching motility is modulated by cAMP levels, mutants lacking FimV are twitching impaired, even when exogenous cAMP is provided. Here we further define FimV’s cAMP-dependent and -independent regulation of twitching. We confirmed that the response regulator of the T4aP-associated Chp chemotaxis system, PilG, required both FimV and the CyaB regulator, FimL, to activate CyaB. However, in cAMP-replete backgrounds - lacking the cAMP phosphodiesterase CpdA or the CheY-like protein PilH, or expressing constitutively-active CyaB - pilG and fimV mutants failed to twitch. Both cytoplasmic and periplasmic domains of FimV were important for its cAMP-dependent and -independent roles, while its septal peptidoglycan-targeting LysM motif was required only for twitching motility. Polar localization of the sensor kinase PilS, a key regulator of transcription of the major pilin, was FimV-dependent. However, unlike its homologues in other species that localize flagellar system components, FimV was not required for swimming motility. These data provide further evidence to support FimV’s role as a key hub protein that coordinates the polar localization and function of multiple structural and regulatory proteins involved in P. aeruginosa twitching motility.IMPORTANCEPseudomonas aeruginosa is a serious opportunistic pathogen. Type IVa pili (T4aP) are important for its virulence, because they mediate dissemination and invasion via twitching motility, and are involved in surface sensing which modulates pathogenicity via changes in cAMP levels. Here we show that the hub protein FimV and the response regulator of the Chp system, PilG, regulate twitching independently of their roles in modulation of cAMP synthesis. These functions do not require the putative scaffold protein FimL, proposed to link PilG with FimV. PilG may regulate asymmetric functioning of the T4aP system to allow for directional movement, while FimV appears to localize both structural and regulatory elements – including the PilSR two-component system – to cell poles for optimal function.

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Extragenic suppressor mutations that restore twitching motility to fimL mutants of Pseudomonas aeruginosa are associated with elevated intracellular cyclic AMP levels

Cited by 13 publications

References 36 publications

Bacterial Cyclic AMP-Phosphodiesterase Activity Coordinates Biofilm Formation

Bacterial Cyclic AMP-Phosphodiesterase Activity Coordinates Biofilm Formation

Cyclic AMP-Independent Control of Twitching Motility in Pseudomonas aeruginosa

cAMP-independent control of twitching motility inPseudomonas aeruginosa

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