Identification of an intracellular M17 family leucine aminopeptidase that is required for virulence in Staphylococcus aureus

Carroll, Rachel; Robison, Tiffany Marie; Rivera, Frances E.; Davenport, Jessica E.; Jonsson, Ing-Marie; Florczyk, Danuta; Tarkowski, Andrej; Potempa, Jan; Kozieł, Joanna; Shaw, Lindsey N.

doi:10.1016/j.micinf.2012.04.013

Cited by 39 publications

(51 citation statements)

References 43 publications

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“…Our previous work, identifying a role in virulence for an S. aureus amino-terminal protease (Carroll et al, 2012(Carroll et al, , 2013, led us to investigate the role of the solitary C-terminal processing enzyme in this important human pathogen. Previous studies on this unusual and somewhat cryptic family of enzymes in prokaryotes have been carried out CtpA is required for virulence in S. aureus.…”

Section: Discussionmentioning

confidence: 99%

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The lone S41 family C-terminal processing protease in Staphylococcus aureus is localized to the cell wall and contributes to virulence

et al. 2014

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Staphylococcus aureus is a versatile pathogen of humans and a continued public health concern due to the rise and spread of multidrug-resistant strains. As part of an ongoing investigation into the pathogenic mechanisms of this organism we previously demonstrated that an intracellular Nterminal processing protease is required for S. aureus virulence. Following on from this, here we examine the role of CtpA, the lone C-terminal processing protease of S. aureus. CtpA, a member of the S41 family, is a serine protease whose homologues in Gram-negative bacteria have been implicated in a range of biological functions, including pathogenesis. We demonstrate that S. aureus CtpA is localized to the bacterial cell wall and expression of the ctpA gene is maximal upon exposure to conditions encountered during infection. Disruption of the ctpA gene leads to decreased heat tolerance and increased sensitivity when exposed to components of the host immune system. Finally we demonstrate that the ctpA " mutant strain is attenuated for virulence in a murine model of infection. Our results represent the first characterization of a C-terminal processing protease in a pathogenic Gram-positive bacterium and show that it plays a critical role during infection.

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Section: Discussionmentioning

confidence: 99%

“…Strains were confirmed by PCR analysis. Western immunoblots to detect CtpA-his were performed as described previously using a monoclonal anti-histidine antibody (Covance) (Carroll et al, 2012(Carroll et al, , 2013. S. aureus cells expressing the plasmid-encoded CtpA-his were grown in TSB overnight and bacteria were collected by centrifugation.…”

Section: Methodsmentioning

confidence: 99%

The lone S41 family C-terminal processing protease in Staphylococcus aureus is localized to the cell wall and contributes to virulence

et al. 2014

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“…An rpoE transposon mutant in S. aureus USA300 strain JE2 was acquired from the Nebraska transposon library (NARSA). This mutation was transferred via 11 transduction to our USA300 Houston wild-type strain (18). Successful transduction of this mutation was confirmed by PCR, using gene-specific (OL1709 and OL1710) and transposon-specific (OL14721 and OL1472) primers.…”

Section: Methodsmentioning

confidence: 96%

The δ Subunit of RNA Polymerase Guides Promoter Selectivity and Virulence in Staphylococcus aureus

et al. 2014

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In Gram-positive bacteria, and particularly the Firmicutes, the DNA-dependent RNA polymerase (RNAP) complex contains an additional subunit, termed the ␦ factor, or RpoE. This enigmatic protein has been studied for more than 30 years for various organisms, but its function is still not well understood. In this study, we investigated its role in the major human pathogen Staphylococcus aureus. We showed conservation of important structural regions of RpoE in S. aureus and other species and demonstrated binding to core RNAP that is mediated by the ␤ and/or ␤= subunits. To identify the impact of the ␦ subunit on transcription, we performed transcriptome sequencing (RNA-seq) analysis and observed 191 differentially expressed genes in the rpoE mutant. Ontological analysis revealed, quite strikingly, that many of the downregulated genes were known virulence factors, while several mobile genetic elements (SaPI5 and prophage SA3usa) were strongly upregulated. Phenotypically, the rpoE mutant had decreased accumulation and/or activity of a number of key virulence factors, including alpha toxin, secreted proteases, and Panton-Valentine leukocidin (PVL). We further observed significantly decreased survival of the mutant in whole human blood, increased phagocytosis by human leukocytes, and impaired virulence in a murine model of infection. Collectively, our results demonstrate that the ␦ subunit of RNAP is a critical component of the S. aureus transcription machinery and plays an important role during infection. Bacterial gene transcription is a complex, multifactorial process that involves several key enzymes and regulatory elements. It is driven by the activity of DNA-dependent RNA polymerase (RNAP) and its associated proteins, which form a multisubunit enzyme consisting of one ␤ subunit, one ␤= subunit, two identical ␣ subunits, and one subunit (reviewed in reference 1). Together these form the RNAP apoenzyme, which is able to perform RNA elongation and termination; however, initiation requires the involvement of a factor. Typically, most bacterial species harbor several different factors, a primary one ( A or 70 ) that mediates housekeeping gene transcription and a variety of alternative sigma factors, which aid in the response to unfavorable environmental conditions and stress.In certain Gram-positive species and particularly the Firmicutes (see Fig. S1 in the supplemental material), an additional RNAP subunit is present, termed the ␦ factor, or RpoE (2). In Bacillus subtilis, the 173-amino-acid delta subunit has been shown to reduce nonspecific binding of RNAP to DNA and lead to an elevated preference for DNA regions that include promoter sequences (3, 4). In early experiments, it was shown that RpoE has a role specifically confined to promoter selection and influences the ability of RNAP to form open promoter complexes (5, 6). Fulllength RpoE has also been described as displacing nucleic acids from RNAP-DNA or RNAP-RNA complexes in vitro, which may explain the decreased affinity of RNAP-RpoE for nonpromoter regions. Thi...

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“…Just to give some examples, the causality of mice infections and survival in human microphages by S. aureus were influenced by a leucine aminopeptidase. 8 Two glycolytic enzymes, aldolase (FbaA) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), affected the virulence ability of S. aureus. FbaA displayed high-level cytotoxicity to both MonoMac 6 (MM6) and HaCa T cells, while GAPDH was cytotoxic only to MM6 cells.…”

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What is behind the epidemiological difference between community-acquired and health-care associated methicillin-resistant Staphylococcus aureus?

Figueiredo

2017

Virulence

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Identification of an intracellular M17 family leucine aminopeptidase that is required for virulence in Staphylococcus aureus

Cited by 39 publications

References 43 publications

The lone S41 family C-terminal processing protease in Staphylococcus aureus is localized to the cell wall and contributes to virulence

The lone S41 family C-terminal processing protease in Staphylococcus aureus is localized to the cell wall and contributes to virulence

The δ Subunit of RNA Polymerase Guides Promoter Selectivity and Virulence in Staphylococcus aureus

What is behind the epidemiological difference between community-acquired and health-care associated methicillin-resistant Staphylococcus aureus?

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