Lipoprotein Signal Peptides Are Processed by Lsp and Eep of
            <i>Streptococcus uberis</i>

Denham, Emma L.; Ward, Philip N.; Leigh, James A.

doi:10.1128/jb.00287-08

Cited by 23 publications

(31 citation statements)

References 49 publications

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“…Henneke et al (2008) also demonstrated that ScaA was further processed by a distinct signal peptidase activity and released into culture supernatants of an lgt/lsp double mutant. Similarly, the Eep peptidase has been shown to act on lipoprotein precursors in Streptococcus uberis (Denham et al, 2008). In contrast to their results for ScaA, and our results for MtsA and SAK_0932, Henneke et al (2008) did not detect any cell-associated Lmb in their lgt mutant but did show that a form of Lmb was released into culture supernatants.…”

Section: Effect Of Lgt Inactivation On Lipoprotein Processingcontrasting

confidence: 56%

Impact of lgt mutation on lipoprotein biosynthesis and in vitro phenotypes of Streptococcus agalactiae

2009

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Although Streptococcus agalactiae, the group B Streptococcus, is a leading cause of invasive neonatal disease worldwide the molecular basis of its virulence is still poorly understood. To investigate the role of lipoproteins in the physiology and interaction of this pathogen with host cells, we generated a mutant S. agalactiae strain (A909DLgt) deficient in the Lgt enzyme and thus unable to lipidate lipoprotein precursors (pro-lipoproteins). The loss of pro-lipoprotein lipidation did not affect the viability of S. agalactiae or its growth in several different media, including cationdepleted media. The processing of two well-characterized lipoproteins, but not a non-lipoprotein, was clearly shown to be aberrant in A909DLgt. The mutant strain was shown to be more sensitive to oxidative stress in vitro although the molecular basis of this increased sensitivity was not apparent. The inactivation of Lgt also resulted in changes to the bacterial cell envelope, as demonstrated by reduced retention of both the group B carbohydrate and the polysaccharide capsule and a statistically significant reduction (P50.0079) in A909DLgt adherence to human endothelial cells of fetal origin. These data confirm that failure to process lipoproteins correctly has pleiotropic effects that may be of significance to S. agalactiae colonization and pathogenesis.

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Section: Effect Of Lgt Inactivation On Lipoprotein Processingcontrasting

confidence: 56%

Impact of lgt mutation on lipoprotein biosynthesis and in vitro phenotypes of Streptococcus agalactiae

2009

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“…Although XIP import is thought to be mediated by an Opp system, our results did not demonstrate a role of Eep in the response to XIP. The presence of alternative mechanisms to process lipoprotein signal peptides have, however, been reported in streptococci (7). Therefore, we cannot exclude the possibility that functional redundancy may obscure a role for Eep in the assembly of a functional Opp system.…”

Section: Figmentioning

confidence: 81%

“…Comparison of Eep in these strains with S. mutans UA159 Eep revealed identities of 52%, 66%, 70%, 67%, and 68%, respectively. In E. faecalis, Eep processes pheromones involved in plasmid conjugation (3,4), and in the listed streptococci, it has been associated with pheromone (6,10,40) or lipoprotein (7,9) processing. To assess whether ComS processing involves the Eep homologue in S. mutans, samples prepared from the supernatants of an eep deletion mutant were run in the LC-LTQ-Orbitrap.…”

Section: Identification Of Processed Xip In the Supernatants Of S Mumentioning

confidence: 99%

Extracellular Identification of a Processed Type II ComR/ComS Pheromone of Streptococcus mutans

et al. 2012

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The competence-stimulating peptide (CSP) and the sigX-inducing peptide (XIP) are known to induce Streptococcus mutans competence for genetic transformation. For both pheromones, direct identification of the native peptides has not been accomplished. The fact that extracellular XIP activity was recently observed in a chemically defined medium devoid of peptides, as mentioned in an accompanying paper (K. Desai, L. Mashburn-Warren, M. J. Federle, and D. A. Morrison, J. Bacteriol. 194:3774 -3780, 2012), provided ideal conditions for native XIP identification. To search for the XIP identity, culture supernatants were filtered to select for peptides of less than 3 kDa, followed by C 18 extraction. One peptide, not detected in the supernatant of a comS deletion mutant, was identified by tandem mass spectrometry (MS/MS) fragmentation as identical to the ComS C-terminal sequence GLDWWSL. ComS processing did not require Eep, a peptidase involved in processing or import of bacterial small hydrophobic peptides, since eep deletion had no inhibitory effect on XIP production or on synthetic XIP response. We investigated whether extracellular CSP was also produced. A reporter assay for CSP activity detection, as well as MS analysis of supernatants, revealed that CSP was not present at detectable levels. In addition, a mutant with deletion of the CSP-encoding gene comC produced endogenous XIP levels similar to those of a nondeletion mutant. The results indicate that XIP pheromone production is a natural phenomenon that may occur in the absence of natural CSP pheromone activity and that the heptapeptide GLDWWSL is an extracellular processed form of ComS, possibly the active XIP pheromone. This is the first report of direct identification of a ComR/ComS pheromone.

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“…Indeed, several studies have now used immunoblotting to reveal different effects on the processing of specific lipoproteins in the same mutant background. The identification of the 'mature-like' lipoprotein forms indicates that the build-up of lipoprotein precursors in the membranes of lgt and lsp mutant strains could result in alternative processing by other peptidases such as the recently recognized Eep peptidase [36], Lsp (in Lgt mutant backgrounds) [28,29] or type 1 signal peptidases. The release of 'mature-like' forms from some lipoprotein precursors in lgt or lsp deletion mutants has been termed 'shaving', whereas the release of either lipoprotein precursors or mature, lipidated lipoproteins can be considered as 'shedding' [37].…”

Section: Reviewmentioning

confidence: 99%

Lipoprotein biogenesis in Gram-positive bacteria: knowing when to hold ‘em, knowing when to fold ‘em

Hutchings

Palmer

Harrington

et al. 2009

Trends in Microbiology

181

219

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Lipoprotein Signal Peptides Are Processed by Lsp and Eep of Streptococcus uberis

Cited by 23 publications

References 49 publications

Impact of lgt mutation on lipoprotein biosynthesis and in vitro phenotypes of Streptococcus agalactiae

Impact of lgt mutation on lipoprotein biosynthesis and in vitro phenotypes of Streptococcus agalactiae

Extracellular Identification of a Processed Type II ComR/ComS Pheromone of Streptococcus mutans

Lipoprotein biogenesis in Gram-positive bacteria: knowing when to hold ‘em, knowing when to fold ‘em

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