Novel surface attachment mechanism of the Streptococcus pneumoniae protein PspA

Yother, Janet; White, Johanna

doi:10.1128/jb.176.10.2976-2985.1994

Cited by 224 publications

(212 citation statements)

References 67 publications

(63 reference statements)

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“…Even in the presence of 1 % choline, which should elute any LytA attached to TA and LTA in the pneumococcal cell wall, no band corresponding to LytA could be identified on the Western blots. This negative result is in accordance with data published by Yother & White (1994), who concluded that LytA is probably an intracellular protein. As we applied a very sensitive detection system for His-tagged proteins, and concentrated our supernatant samples 70-fold, our assay must be considered significantly more sensitive than the one employed by Yother & White (1994).…”

Section: Discussionsupporting

confidence: 93%

Fratricide in Streptococcus pneumoniae: contributions and role of the cell wall hydrolases CbpD, LytA and LytC

et al. 2009

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Pneumococci that have developed the competent state kill and lyse non-competent sister cells and members of closely related species during co-cultivation in vitro. The key component in this process, called fratricide, is the product of the late competence gene cbpD. In addition, the peptidoglycan hydrolases LytA and LytC are required for efficient lysis of target cells. Here, we have investigated the relative contribution and possible role of each of the proteins mentioned above. Previous studies have shown that CbpD is produced exclusively by competent cells, whereas LytA and LytC can be provided by the competent attackers as well as the non-competent target cells. By using an improved assay to compare the effect of cis-versus trans-acting LytA and LytC, we were able to show that target cells are lysed much more efficiently when LytA and LytC are provided in cis, i.e. by the target cells themselves. Western analysis demonstrated that considerable amounts of LytC are present in the growth medium. In contrast, we were not able to detect any extracellular LytA. This finding indicates that LytA-and LytC-mediated fratricide represent different processes. In the absence of LytA and LytC, only a tiny fraction of the target cells were lysed, demonstrating that CbpD does not function efficiently on its own. However, in the presence of 1 mM EDTA, the fraction of target cells lysed directly by CbpD increased dramatically, indicating that divalent cations are involved in the regulation of fratricide under natural conditions.

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Section: Discussionsupporting

confidence: 93%

Fratricide in Streptococcus pneumoniae: contributions and role of the cell wall hydrolases CbpD, LytA and LytC

et al. 2009

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“…Depending on the number of repeats in the choline-binding domain, the CBPs are more weakly or strongly attached to the surface of the bacterium as well as an absolute requirement for substrate binding. This property has been shown for both PspA and LytA (Sanchez et al, 1990;Lopez et al, 1992;Garcia et al, 1994;Yother and White, 1994).…”

Section: Discussionmentioning

confidence: 55%

Contribution of novel choline‐binding proteins to adherence, colonization and immunogenicity of Streptococcus pneumoniae

Rosenow

Ryan

Weiser

et al. 1997

Molecular Microbiology

437

465

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SummaryThe surface of Streptococcus pneumoniae is decorated with a family of choline-binding proteins (CBPs) that are non-covalently bound to the phosphorylcholine of the teichoic acid. Two examples (PspA, a protective antigen, and LytA, the major autolysin) have been well characterized. We identified additional CPBs and characterized a new CBP, CbpA, as an adhesin and a determinant of virulence. Using choline immobilized on a solid matrix, a mixture of proteins from a pspA-deficient strain of pneumococcus was eluted in a choline-dependent fashion. Antisera to these proteins passively protected mice challenged in the peritoneum with a lethal dose of pneumococci. The predominant component of this mixture, CbpA, is a 75-kDa surface-exposed protein that reacts with human convalescent antisera. The deduced sequence from the corresponding gene showed a chimeric architecture with a unique N-terminal region and a C-terminal domain consisting of 10 repeated choline-binding domains nearly identical to PspA. A cbpA-deficient mutant showed a >50% reduction in adherence to cytokine-activated human cells and failed to bind to immobilized sialic acid or lacto-N-neotetraose, known pneumococcal ligands on eukaryotic cells. Carriage of this mutant in an animal model of nasopharyngeal colonization was reduced 100-fold. There was no difference between the parent strain and this mutant in an intraperitoneal model of sepsis. These data for CbpA extend the important functions of the CBP family to bacterial adherence and identify a pneumococcal vaccine candidate.

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“…To evaluate the presence of SsEno in different bacterial compartments, S. suis strain 1669 was grown overnight at 37 uC with agitation in 30 ml THB. The subcellular components (supernatant, cell wall, cytoplasmic and membrane fractions) were fractionated with mutanolysin by using the method of Yother & White (1994). Equivalent amounts of all fractions were analysed by SDS-PAGE (12.5 % polyacrylamide) and Western blotting using optimally diluted rabbit anti-SsEno IgG.…”

Section: Methodsmentioning

confidence: 99%

Isolation and characterization of α-enolase, a novel fibronectin-binding protein from Streptococcus suis

et al. 2008

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Streptococcus suis is an important swine pathogen that causes meningitis, endocarditis, arthritis and septicaemia. As a zoonotic agent, S. suis also causes similar diseases in humans. Binding of pathogenic bacteria to extracellular matrix components enhances their adhesion to and invasion of host cells. In the present study we isolated and identified a novel fibronectin-binding protein from S. suis. The native protein (designated SsEno) possessed not only high homology with other bacterial enolases but also enolase activity. We cloned, expressed and purified SsEno and showed that it is ubiquitously expressed by all S. suis serotypes and we identified its surface localization using immunoelectron microscopy. ELISA demonstrated that SsEno binds specifically to fibronectin and plasminogen in a lysine-dependent manner. Additional surface plasmon resonance assays demonstrated that SsEno binds to fibronectin or plasminogen with low nanomolar affinity. Inhibition experiments with anti-SsEno antibodies also showed that bacterial SsEno is important for the adhesion to and invasion of brain microvascular endothelial cells by S. suis. Overall, the present work is the first study, to our knowledge, to demonstrate a fibronectinbinding activity of a bacterial enolase, and shows that, similar to other bacterial fibronectin-binding proteins, SsEno may contribute to the virulence of S. suis. INTRODUCTIONStreptococcus suis is a major swine pathogen that causes septicaemia, meningitis, endocarditis and arthritis (Higgins & Gottschalk, 2005). Of the 35 known serotypes, serotype 2 is the most frequently isolated and associated with disease (Higgins & Gottschalk, 2005). It has been proposed that two serotypes (serotypes 32 and 34) be excluded from S. suis and redesignated Streptococcus orisratti (Hill et al., 2005). S. suis, especially serotype 2, has also been described as an important zoonotic agent that affects people in close contact with infected pigs or pork-derived products (Lun et al., 2007). Indeed, an important number of cases of human disease with a high rate of mortality in China were linked directly to a concurrent outbreak of S. suis infection in pigs (Ye et al., 2006).Little is known about S. suis virulence factors. The capsule polysaccharide (CPS) is a critical virulence factor, given that unencapsulated isogenic mutants are completely avirulent and rapidly cleared from the circulation in pig and mouse infection models (Charland et al., 2000;Smith et al., 1999). However, non-virulent strains are also encapsulated, indicating that the virulence of this pathogen is a multifactorial process . Other potential virulence factors have also been described in S. suis, including a haemolysin (suilysin), a 136 kDa muramidase-released protein (MRP), a 110 kDa extracellular factor (EF) protein, a hyaluronidase, a superoxide dismutase, various proteases, a serum opacity factor and different adhesins (Baums et al., 2006;.The pathogenesis of S. suis infection is not fully understood and likely involves many steps . Binding between b...

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Novel surface attachment mechanism of the Streptococcus pneumoniae protein PspA

Cited by 224 publications

References 67 publications

Fratricide in Streptococcus pneumoniae: contributions and role of the cell wall hydrolases CbpD, LytA and LytC

Fratricide in Streptococcus pneumoniae: contributions and role of the cell wall hydrolases CbpD, LytA and LytC

Contribution of novel choline‐binding proteins to adherence, colonization and immunogenicity of Streptococcus pneumoniae

Isolation and characterization of α-enolase, a novel fibronectin-binding protein from Streptococcus suis

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