The Early Response to Acid Shock in<i>Lactobacillus reuteri</i>Involves the ClpL Chaperone and a Putative Cell Wall-Altering Esterase

Wall, Torun; Båth, Klara; Britton, Robert A.; Jonsson, Hans; Versalovic, James; Roos, Stefan

doi:10.1128/aem.01502-06

Cited by 116 publications

(97 citation statements)

References 66 publications

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“…Notably, growth under acidic conditions can induce clpL expression, as demonstrated in lactobacilli (45). The situation is probably similar in S. mutans, since the ClpL protein was produced in larger amounts when cells are grown at pH 5.0 than when they are grown at pH 7.0 (34).…”

Section: Discussionmentioning

confidence: 98%

“…ClpL has never been reported to be involved in a specific protein degradation process. ClpL belongs to the HSP100/Clp ATPase family and has been shown to be important for the stress tolerance response in some organisms (15,41,42,45). Apart from its putative chaperone function and involvement in stress tolerance, very little is known about ClpL ATPase activity.…”

Section: Discussionmentioning

confidence: 99%

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CtsR Regulation in mcsAB -Deficient Gram-Positive Bacteria

2012

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CtsR is an important repressor that modulates the transcription of class III stress genes in Gram-positive bacteria. In Bacillus subtilis, a model Gram-positive organism, the DNA binding activity of CtsR is regulated by McsAB-mediated phosphorylation of the protein where phosphorylated CtsR is a substrate for degradation by the ClpCP complex. Surprisingly, the mcsAB genes are absent from many Gram-positive bacteria, including streptococci; therefore, how CtsR activity is modulated in those bacteria remains unknown. Here we show that the posttranslational modulation of CtsR activity is different in Streptococcus mutans, a dental pathogen. We observed that of all of the Clp-related proteins, only ClpL is involved in the degradation of CtsR. Neither ClpP nor ClpC had any effect on the degradation of CtsR. We also found that phosphorylation of CtsR on a conserved arginine residue within the winged helix-turn-helix domain is necessary for modulation of the repressor activity of CtsR, as demonstrated by both in vitro and in vivo assays. We speculate that CtsR is regulated posttranslationally by a different mechanism in S. mutans and possibly in other streptococci.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

CtsR Regulation in mcsAB -Deficient Gram-Positive Bacteria

2012

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“…A role for ClpL in the acid tolerance of lactic acid bacteria is further illustrated by studies with Lactobacillus species. For Lactobacillus reuteri, clpL was upregulated during acid shock, and a clpL mutant was significantly more sensitive to low pH than the parental strain (40). Similarly, a proteomic approach identified ClpL as upregulated during the acid adaptation of Lactobacillus bulgaricus (14).…”

Section: Discussionmentioning

confidence: 98%

Role of Clp Proteins in Expression of Virulence Properties ofStreptococcus mutans

Martinez²,

et al. 2009

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Mutational analysis revealed that members of the Clp system, specifically the ClpL chaperone and the ClpXP proteolytic complex, modulate the expression of important virulence attributes of Streptococcus mutans. Compared to its parent, the ⌬clpL strain displayed an enhanced capacity to form biofilms in the presence of sucrose, had reduced viability, and was more sensitive to acid killing. The ⌬clpP and ⌬clpX strains displayed several phenotypes in common: slow growth, tendency to aggregate in culture, reduced autolysis, and reduced ability to grow under stress, including acidic pH. Unexpectedly, the ⌬clpP and ⌬clpX mutants were more resistant to acid killing and demonstrated enhanced viability in long-term survival assays. Biofilm formation by the ⌬clpP and ⌬clpX strains was impaired when grown in glucose but enhanced in sucrose. In an animal study, the average number of S. mutans colonies recovered from the teeth of rats infected with the ⌬clpP or ⌬clpX strain was slightly lower than that of the parent strain. In Bacillus subtilis, the accumulation of the Spx global regulator, a substrate of ClpXP, has accounted for the ⌬clpXP phenotypes. Searching the S. mutans genome, we identified two putative spx genes, designated spxA and spxB. The inactivation of either of these genes bypassed phenotypes of the clpP and clpX mutants. Western blotting demonstrated that Spx accumulates in the ⌬clpP and ⌬clpX strains. Our results reveal that the proteolysis of ClpL and ClpXP plays a role in the expression of key virulence traits of S. mutans and indicates that the underlying mechanisms by which ClpXP affect virulence traits are associated with the accumulation of two Spx orthologues.

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“…In other bacteria, esterases have been linked to virulence and pathogenesis (Lun and Bishai, 2007;Wall et al, 2007;Zhu et al, 2009). These studies highlight the importance of esterases and point toward the need for the study of the potential role of S. mutans esterases in aciduricity, virulence, and pathogenesis (i.e., dental caries).…”

Section: Discussionmentioning

confidence: 99%

Cariogenic Bacteria Degrade Dental Resin Composites and Adhesives

et al. 2013

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A major reason for dental resin composite restoration replacement is related to secondary caries promoted by acid production from bacteria including Streptococcus mutans (S. mutans). We hypothesized that S. mutans has esterase activities that degrade dental resin composites and adhesives. Standardized specimens of resin composite (Z250), total-etch (Scotchbond Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 or uninoculated culture medium (control) for up to 30 days. Quantification of the BisGMA-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP), was performed by high-performance liquid chromatography. Surface analysis of the specimens was performed by scanning electron microscopy (SEM). S. mutans was shown to have esterase activities in levels comparable with those found in human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was more elevated in the presence of bacteria vs. control medium for EB and Z250, but not for SB (p < .05). SEM confirmed the increased degradation of all materials with S. mutans UA159 vs. control. S. mutans has esterase activities at levels that degrade resin composites and adhesives; degree of degradation was dependent on the material's chemical formulation. This finding suggests that the resin-dentin interface could be compromised by oral bacteria that contribute to the progression of secondary caries.

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The Early Response to Acid Shock inLactobacillus reuteriInvolves the ClpL Chaperone and a Putative Cell Wall-Altering Esterase

Cited by 116 publications

References 66 publications

CtsR Regulation in mcsAB -Deficient Gram-Positive Bacteria

CtsR Regulation in mcsAB -Deficient Gram-Positive Bacteria

Role of Clp Proteins in Expression of Virulence Properties ofStreptococcus mutans

Cariogenic Bacteria Degrade Dental Resin Composites and Adhesives

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