spr1630 Is Responsible for the Lethality of<i>clpX</i>Mutations in<i>Streptococcus pneumoniae</i>

Piotrowski, Andrew; Burghout, Peter; Morrison, Donald A.

doi:10.1128/jb.00285-09

Cited by 12 publications

(13 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We obtained viable Δ phpP transformants and characterized them further (see below). To exclude the possibility that the Δ phpP strain might carry an unlinked extragenic suppressor of the potentially lethal effect of loss of PhpP, the dose-response pattern for Δ phpP versus a wild type (WT) backcross was determined [32, 33]. Transformation by a single marker in pneumococcus displays a linear dependence on the dose of donor DNA (slope of regression curve equal to 1), whereas less efficient co-transformation by two markers follows a quadratic dependence on donor DNA dose (slope of regression curve equal to 2).…”

Section: Resultsmentioning

confidence: 99%

Characterization of pneumococcal Ser/Thr protein phosphatase phpP mutant and identification of a novel PhpP substrate, putative RNA binding protein Jag

et al. 2016

View full text Add to dashboard Cite

BackgroundReversible protein phosphorylation catalyzed by protein kinases and phosphatases is the primary mechanism for signal transduction in all living organisms. Streptococcus pneumoniae encodes a single Ser/Thr protein kinase, StkP, which plays a role in virulence, stress resistance and the regulation of cell wall synthesis and cell division. However, the role of its cognate phosphatase, PhpP, is not well defined.ResultsHere, we report the successful construction of a ΔphpP mutant in the unencapsulated S. pneumoniae Rx1 strain and the characterization of its phenotype. We demonstrate that PhpP negatively controls the level of protein phosphorylation in S. pneumoniae both by direct dephosphorylation of target proteins and by dephosphorylation of its cognate kinase, StkP. Catalytic inactivation or absence of PhpP resulted in the hyperphosphorylation of StkP substrates and specific phenotypic changes, including sensitivity to environmental stresses and competence deficiency. The morphology of the ΔphpP cells resembled the StkP overexpression phenotype and conversely, overexpression of PhpP resulted in cell elongation mimicking the stkP null phenotype. Proteomic analysis of the phpP knock-out strain permitted identification of a novel StkP/PhpP substrate, Spr1851, a putative RNA-binding protein homologous to Jag. Here, we show that pneumococcal Jag is phosphorylated on Thr89. Inactivation of jag confers a phenotype similar to the phpP mutant strain.ConclusionsOur results suggest that PhpP and StkP cooperatively regulate cell division of S. pneumoniae and phosphorylate putative RNA binding protein Jag.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0865-6) contains supplementary material, which is available to authorized users.

show abstract

Section: Resultsmentioning

confidence: 99%

Characterization of pneumococcal Ser/Thr protein phosphatase phpP mutant and identification of a novel PhpP substrate, putative RNA binding protein Jag

et al. 2016

View full text Add to dashboard Cite

show abstract

“…These defects are mostly due to accumulation of a transcriptional regulator, Spx, that is normally degraded by ClpXP. ClpX or ClpP has, however, been found to be essential in several bacteria, including the pathogens Mycobacterium tuberculosis and Streptococcus pneumoniae (Piotrowski et al, 2009; Raju et al, 2012). The essentiality of clpX can be bypassed in Streptococcus by mutations in an uncharacterized gene, spr1630 , suggesting that this gene product may accumulate in the absence of ClpXP and inhibit growth, similar to SocB.…”

Section: Discussionmentioning

confidence: 99%

A Bacterial Toxin Inhibits DNA Replication Elongation through a Direct Interaction with the β Sliding Clamp

et al. 2013

View full text Add to dashboard Cite

SUMMARY Toxin-antitoxin (TA) systems are ubiquitous on bacterial chromosomes, yet the mechanisms regulating their activity, and the molecular targets of toxins, remain incompletely understood. Here, we identify SocAB, a new TA system in Caulobacter crescentus. Unlike canonical TA systems, the toxin SocB is unstable and constitutively degraded by the protease ClpXP; this degradation requires the antitoxin, SocA, as a proteolytic adaptor. We find that the toxin, SocB, blocks replication elongation through an interaction with the sliding clamp, driving replication fork collapse. Mutations that suppress SocB toxicity map to either the hydrophobic cleft on the clamp that binds DNA polymerase III or a clamp-binding motif in SocB. Our findings suggest that SocB disrupts replication by outcompeting other clamp-binding proteins. Collectively, our results expand the diversity of mechanisms employed by TA systems to regulate toxin activity and inhibit bacterial growth, and they suggest that inhibiting clamp function may be a generalizable antibacterial strategy.

show abstract

“…1A, two genes, dhfr (encoding dihydrofolate reductase) and clpX, are located downstream of dpr in the TIGR4 pneumococcal genome. These two genes have been previously shown to be essential in pneumococcus (30)(31)(32). In two published studies, attempts to generate a dpr mutant failed (1,18).…”

Section: Resultsmentioning

confidence: 99%

Effect of Nonheme Iron-Containing Ferritin Dpr in the Stress Response and Virulence of Pneumococci

et al. 2014

View full text Add to dashboard Cite

bStreptococcus pneumoniae (pneumococcus) produces hydrogen peroxide as a by-product of metabolism and provides a competitive advantage against cocolonizing bacteria. As pneumococci do not produce catalase or an inducible regulator of hydrogen peroxide, the mechanism of resistance to hydrogen peroxide is unclear. A gene responsible for resistance to hydrogen peroxide and iron in other streptococci is that encoding nonheme iron-containing ferritin, dpr, but previous attempts to study this gene in pneumococcus by generating a dpr mutant were unsuccessful. In the current study, we found that dpr is in an operon with the downstream genes dhfr and clpX. We generated a dpr deletion mutant which displayed normal early-log-phase and mid-logphase growth in bacteriologic medium but survived less well at stationary phase; the addition of catalase partially rescued the growth defect. We showed that the dpr mutant is significantly more sensitive to pH, heat, iron concentration, and oxidative stress due to hydrogen peroxide. Using a mouse model of colonization, we also showed that the dpr mutant displays a reduced ability to colonize and is more rapidly cleared from the nasopharynx. Our results thus suggest that Dpr is important for pneumococcal resistance to stress and for nasopharyngeal colonization.

show abstract

spr1630 Is Responsible for the Lethality ofclpXMutations inStreptococcus pneumoniae

Cited by 12 publications

References 50 publications

Characterization of pneumococcal Ser/Thr protein phosphatase phpP mutant and identification of a novel PhpP substrate, putative RNA binding protein Jag

Characterization of pneumococcal Ser/Thr protein phosphatase phpP mutant and identification of a novel PhpP substrate, putative RNA binding protein Jag

A Bacterial Toxin Inhibits DNA Replication Elongation through a Direct Interaction with the β Sliding Clamp

Effect of Nonheme Iron-Containing Ferritin Dpr in the Stress Response and Virulence of Pneumococci

Contact Info

Product

Resources

About