Control of Natural Transformation in Salivarius Streptococci through Specific Degradation of σ
            <sup>X</sup>
            by the MecA-ClpCP Protease Complex

Wahl, Astrid Klopstad; Servais, Florence; Drucbert, Anne-Sophie; Foulon, Catherine; Fontaine, Laetitia; Hols, Pascal

doi:10.1128/jb.01758-14

Cited by 26 publications

(42 citation statements)

References 41 publications

(126 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is important, since MecA is ubiquitous among streptococci and its homologs are found in the complete genomes of all species sequenced so far [34,35]. In a most recent study, Wahl et al have provided convincing in vitro evidence that confirms the importance of MecA-ClpCP complex in the posttranslational regulation of SigX in S. thermophilus [40]. However, their work has not described how MecA is regulated in vivo under test growth conditions.…”

Section: Discussionmentioning

confidence: 99%

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

et al. 2014

View full text Add to dashboard Cite

BackgroundSigX (σX), the alternative sigma factor of Streptococcus mutans, is the key regulator for transcriptional activation of late competence genes essential for taking up exogenous DNA. Recent studies reveal that adaptor protein MecA and the protease ClpC act as negative regulators of competence by a mechanism that involves MecA-mediated proteolysis of SigX by the ClpC in S. mutans. However, the molecular detail how MecA and ClpC negatively regulate competence in this species remains to be determined. Here, we provide evidence that adaptor protein MecA targets SigX for degradation by the protease complex ClpC/ClpP when S. mutans is grown in a complex medium.ResultsBy analyzing the cellular levels of SigX, we demonstrate that the synthesis of SigX is transiently induced by competence-stimulating peptide (CSP), but the SigX is rapidly degraded during the escape from competence. A deletion of MecA, ClpC or ClpP results in the cellular accumulation of SigX and a prolonged competence state, while an overexpression of MecA enhances proteolysis of SigX and accelerates the escape from competence. In vitro protein-protein interaction assays confirm that MecA interacts with SigX via its N-terminal domain (NTD1–82) and with ClpC via its C-terminal domain (CTD123–240). Such an interaction mediates the formation of a ternary SigX-MecA-ClpC complex, triggering the ATP-dependent degradation of SigX in the presence of ClpP. A deletion of the N-terminal or C-terminal domain of MecA abolishes its binding to SigX or ClpC. We have also found that MecA-regulated proteolysis of SigX appears to be ineffective when S. mutans is grown in a chemically defined medium (CDM), suggesting the possibility that an unknown mechanism may be involved in negative regulation of MecA-mediated proteolysis of SigX under this condition.ConclusionAdaptor protein MecA in S. mutans plays a crucial role in recognizing and targeting SigX for degradation by the protease ClpC/ClpP. Thus, MecA actually acts as an anti-sigma factor to regulate the stability of SigX during competence development.

show abstract

Section: Discussionmentioning

confidence: 99%

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In streptococci, competence is a transient physiological bacterial state (Seaton et al, 2011, 2015; Desai et al, 2012; Federle and Morrison, 2012; Guo et al, 2014) and the mechanisms mediating shut-down have only been partially elucidated in some species (Boutry et al, 2012; Tian et al, 2013; Weng et al, 2013; Dong et al, 2014; Wahl et al, 2014). In S. pneumoniae , which possess the ComCDE competence regulatory system, the exit from competence is regulated by multiple ComX dependent- and independent mechanisms (Chastanet et al, 2001; Bergé et al, 2003; Mortier-Barrière et al, 2007; Piotrowski et al, 2009; Martin et al, 2013; Mirouze et al, 2013; Weng et al, 2013) In S. mutans and S. thermophilus which both utilize the ComRS system to regulate competence development, MecA negatively regulates competence development by targeting the ClpC-ClpP protease activity to ComX (Boutry et al, 2012; Tian et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…In S. pneumoniae , which possess the ComCDE competence regulatory system, the exit from competence is regulated by multiple ComX dependent- and independent mechanisms (Chastanet et al, 2001; Bergé et al, 2003; Mortier-Barrière et al, 2007; Piotrowski et al, 2009; Martin et al, 2013; Mirouze et al, 2013; Weng et al, 2013) In S. mutans and S. thermophilus which both utilize the ComRS system to regulate competence development, MecA negatively regulates competence development by targeting the ClpC-ClpP protease activity to ComX (Boutry et al, 2012; Tian et al, 2013). Moreover, in vitro degradation of ComX by ClpC-ClpP was shown to be strictly dependent on MecA (Wahl et al, 2014). …”

Section: Introductionmentioning

confidence: 99%

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Zaccaria

Wels²,

Baarlen

et al. 2016

Front. Microbiol.

View full text Add to dashboard Cite

In S. suis the ComX-inducing peptide (XIP) pheromone regulates ComR-dependent transcriptional activation of comX (or sigX) the regulator of the late competence regulon. The aims of this study were to identify the ComR-regulated genes and in S. suis using genome-wide transcriptomics and identify their function based on orthology and the construction of specific knockout mutants. The ComX regulon we identified, includes all homologs of the “transformasome” a type 4-like pilus DNA binding and transport apparatus identified in Streptococcus pneumoniae, Streptococcus mutans, and Streptococcus thermophilus. A conserved CIN-box (YTACGAAYW), predicted to be bound by ComX, was found in the promoters of operons encoding genes involved in expression of the transformasome. Mutants lacking the major pilin gene comYC were not transformable demonstrating that the DNA uptake pilus is indeed required for competence development in S. suis. Competence was a transient state with the comX regulon shut down after ~15 min even when transcription of comX had not returned to basal levels, indicating other mechanisms control the exit from competence. The ComX regulon also included genes involved in DNA repair including cinA which we showed to be required for high efficiency transformation. In contrast to S. pneumoniae and S. mutans the ComX regulon of S. suis did not include endA which converts the transforming DNA into ssDNA, or ssbA, which protects the transforming ssDNA from degradation. EndA appeared to be essential in S. suis so we could not generate mutants and confirm its role in DNA transformation. Finally, we identified a putative homolog of fratricin, and a putative bacteriocin gene cluster, that were also part of the CIN-box regulon and thus may play a role in DNA release from non-competent cells, enabling gene transfer between S. suis pherotypes or S. suis and other species. S. suis mutants of oppA, the binding subunit of the general oligopeptide transporter were not transformable, suggesting that it is required for the import of XIP.

show abstract

“…Phenotypic characterization of an S. thermophilus clpC mutant revealed that ClpC plays a role in the development of genetic competence in this organism (310). The alternative sigma factor ComX, which drives the expression of competence genes, was shown in S. thermophilus and S. mutans to be under posttranslational regulation by ClpCP through active degradation (310)(311)(312)(313). This task is performed by ClpEP in S. pneumoniae (314).…”

Section: Treating Damaged Macromoleculesmentioning

confidence: 99%

Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

515

404

View full text Add to dashboard Cite

SUMMARYLactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g.,Lactococcus lactis), probiotic (e.g., severalLactobacillusspp.), and pathogenic (e.g.,EnterococcusandStreptococcusspp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

show abstract

Control of Natural Transformation in Salivarius Streptococci through Specific Degradation of σ ^X by the MecA-ClpCP Protease Complex

Cited by 26 publications

References 41 publications

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Stress Physiology of Lactic Acid Bacteria

Contact Info

Product

Resources

About

Control of Natural Transformation in Salivarius Streptococci through Specific Degradation of σ X by the MecA-ClpCP Protease Complex

Cited by 26 publications

References 41 publications

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

Regulated proteolysis of the alternative sigma factor SigX in Streptococcus mutans: implication in the escape from competence

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Stress Physiology of Lactic Acid Bacteria

Contact Info

Product

Resources

About

Control of Natural Transformation in Salivarius Streptococci through Specific Degradation of σ ^X by the MecA-ClpCP Protease Complex