Global analysis of community-associated methicillin-resistant Staphylococcus aureus exoproteins reveals molecules produced in vitro and during infection

Burlak, Christopher; Hammer, Carl H.; Robinson, Mary Ann; Whitney, Adeline R.; McGavin, Martin J.; Kreiswirth, Barry N.; DeLeo, Frank R.

doi:10.1111/j.1462-5822.2006.00858.x

Cited by 161 publications

(117 citation statements)

References 60 publications

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“…Mature 20-kDa SspB mimics plasma serine proteases as noted by its ability to (i) convert high molecular weight kininogen into heavy and light chains, (ii) hydrolyze the Bz-Pro-Phe-Arg substrate of kallikrein, a serine protease that processes single chain kininogen by excision of the vasoactive peptide bradykinin (RPPGFSPFR), (iii) process the N terminus of the fibrinogen ␤-chain at the same site as plasmin, and (iv) remove the N-terminal domain of fibronectin with a specificity equivalent to plasminogen activator (10). We have also found that antibodies to SspB are produced when mice are challenged with hypervirulent strains of community-acquired methicillin-resistant S. aureus and that SspA and SspB are rapidly expressed in neutrophil vacuoles following phagocytosis (11), alluding to a role in modifying vacuolar proteins.…”

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confidence: 68%

Activation of the SspA Serine Protease Zymogen of Staphylococcus aureus Proceeds through Unique Variations of a Trypsinogen-like Mechanism and Is Dependent on Both Autocatalytic and Metalloprotease-specific Processing

Nickerson

Prasad

Jacob

et al. 2007

Journal of Biological Chemistry

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The serine and cysteine proteases SspA and SspB of Staphylococcus aureus are secreted as inactive zymogens, zSspA and zSspB. Mature SspA is a trypsin-like glutamyl endopeptidase and is required to activate zSspB. Although a metalloprotease Aureolysin (Aur) is in turn thought to contribute to activation of zSspA, a specific role has not been demonstrated. We found that pre-zSspA is processed by signal peptidase at ANA 29 Binding of glutamate within the active site of zSspA is energetically unfavorable, but glutamine fits into the primary specificity pocket and is predicted to hydrogen bond to Thr 232 proximal to Ser 237 , permitting autocatalytic cleavage of the glutamine-rich propeptide segment. These and other observations suggest that zSspA is activated through a trypsinogen-like mechanism where supplementary features of the propeptide must be sequentially processed in the correct order to allow efficient activation.Staphylococcus aureus can colonize and infect virtually every tissue and organ system of the body (1, 2). A key factor in these defining traits is its ability to sustain bacteremia and adhere to tissues. Consequently it has adapted to growth in blood by subversion of plasma proteins (3) and the tissue extracellular matrix (4). Members of the MSCRAMM (microbial extracellular matrix-binding protein) family of adhesion proteins bind extracellular matrix ligands such as collagen, fibronectin, and fibrinogen (4) of which the latter two are also abundant in plasma. Manipulation of other plasma proteins such as IgG and von Willebrand factor is facilitated by staphylococcal Protein A (5), whereas coagulase promotes fibrin clot formation by activation of prothrombin (6), and staphylokinase activates plasminogen (7) to facilitate fibrin clot dissolution. Our studies on secreted proteases are also supportive of S. aureus as a paradigm for the manipulation of plasma and coagulation proteins.The SspA 4 glutamyl endopeptidase, also known as V8 protease, moderates adhesion of S. aureus to fibronectin by degrading cell surface fibronectin-binding proteins in which there is a high glutamic acid content, including a conserved motif that is essential for ligand binding (8, 9). SspA is expressed in an operon with a cysteine protease, SspB, and activates the zSspB zymogen by removing its N-terminal propeptide (10). Mature 20-kDa SspB mimics plasma serine proteases as noted by its ability to (i) convert high molecular weight kininogen into heavy and light chains, (ii) hydrolyze the Bz-Pro-Phe-Arg substrate of kallikrein, a serine protease that processes single chain kininogen by excision of the vasoactive peptide bradykinin (RPPGFSPFR), (iii) process the N terminus of the fibrinogen ␤-chain at the same site as plasmin, and (iv) remove the N-terminal domain of fibronectin with a specificity equivalent to plasminogen activator (10). We have also found that antibodies to SspB are produced when mice are challenged with hypervirulent strains of community-acquired methicillin-resistant S. aureus and that SspA and SspB are r...

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confidence: 68%

Activation of the SspA Serine Protease Zymogen of Staphylococcus aureus Proceeds through Unique Variations of a Trypsinogen-like Mechanism and Is Dependent on Both Autocatalytic and Metalloprotease-specific Processing

Nickerson

Prasad

Jacob

et al. 2007

Journal of Biological Chemistry

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“…Aureolysin has been shown to contribute to 1) bacterial spreading and invasion by activating the fibrinolytic system (49), 2) resistance to antimicrobial peptides (26), and 3) inhibition of Ig production by lymphocytes (50). Recent studies suggested that aureolysin can be expressed within the phagocytic vacuole after phagocytosis of S. aureus (51). Furthermore it was shown that the isogenic aureolysin mutant was more efficiently killed by macrophages upon phagocytosis (52).…”

Section: Discussionmentioning

confidence: 99%

Staphylococcus aureus Metalloprotease Aureolysin Cleaves Complement C3 To Mediate Immune Evasion

Laarman

Ruyken

Malone

et al. 2011

The Journal of Immunology

176

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Complement is one of the first host defense barriers against bacteria. Activated complement attracts neutrophils to the site of infection and opsonizes bacteria to facilitate phagocytosis. The human pathogen Staphylococcus aureus has successfully developed ways to evade the complement system, for example by secretion of specific complement inhibitors. However, the influence of S. aureus proteases on the host complement system is still poorly understood. In this study, we identify the metalloprotease aureolysin as a potent complement inhibitor. Aureolysin effectively inhibits phagocytosis and killing of bacteria by neutrophils. Furthermore, we show that aureolysin inhibits the deposition of C3b on bacterial surfaces and the release of the chemoattractant C5a. Cleavage analyses show that aureolysin cleaves the central complement protein C3. Strikingly, there was a clear difference between the cleavages of C3 in serum versus purified conditions. Aureolysin cleaves purified C3 specifically in the α-chain, close to the C3 convertase cleavage site, yielding active C3a and C3b. However, in serum we observe that the aureolysin-generated C3b is further degraded by host factors. We pinpointed these factors to be factor H and factor I. Using an aureolysin mutant in S. aureus USA300, we show that aureolysin is essential and sufficient for C3 cleavage by bacterial supernatant. In short, aureolysin acts in synergy with host regulators to inactivate C3 thereby effectively dampening the host immune response.

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“…All mutant strains were generated in an S. aureus MW2 background with in-frame deletion of target genes by allelic replacement, using the temperature-sensitive plasmid pMAD as described previously (15,30). S. aureus MW2 (USA400), a prototypical clinical methicillin-resistant S. aureus (MRSA) isolate, has been well characterized genotypically (e.g., available genome sequence information) and is virulent in vivo in animal models (31)(32)(33). Briefly, PCR was used to amplify an ϳ2-kb fragment comprising a 1-kb fragment upstream and another 1-kb fragment downstream of graS using genomic DNA as the template.…”

Section: Methodsmentioning

confidence: 99%

Site-Specific Mutation of the Sensor Kinase GraS in Staphylococcus aureus Alters the Adaptive Response to Distinct Cationic Antimicrobial Peptides

et al. 2014

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The Staphylococcus aureus two-component regulatory system, GraRS, is involved in resistance to killing by distinct host defense cationic antimicrobial peptides (HD-CAPs). It is believed to regulate downstream target genes such as mprF and dltABCD to modify the S. aureus surface charge. However, the detailed mechanism(s) by which the histidine kinase, GraS, senses specific HD-CAPs is not well defined. Here, we studied a well-characterized clinical methicillin-resistant S. aureus (MRSA) strain (MW2), its isogenic graS deletion mutant (⌬graS strain), a nonameric extracellular loop mutant (⌬EL strain), and four residuespecific ⌬EL mutants (D37A, P39A, P39S, and D35G D37G D41G strains). The ⌬graS and ⌬EL strains were unable to induce mprF and dltA expression and, in turn, demonstrated significantly increased susceptibilities to daptomycin, polymyxin B, and two prototypical HD-CAPs (hNP-1 and RP-1). Further, P39A, P39S, and D35G-D37G-D41G ⌬EL mutations correlated with moderate increases in HD-CAP susceptibility. Reductions of mprF and dltA induction by PMB were also found in the ⌬EL mutants, suggesting these residues are pivotal to appropriate activation of the GraS sensor kinase. Importantly, a synthetic exogenous soluble EL mimic of GraS protected the parental MW2 strain against hNP-1-and RP-1-mediated killing, suggesting a direct interaction of the EL with HD-CAPs in GraS activation. In vivo, the ⌬graS and ⌬EL strains displayed dramatic reductions in achieved target tissue MRSA counts in an endocarditis model. Taken together, our results provide new insights into potential roles of GraS in S. aureus sensing of HD-CAPs to induce adaptive survival responses to these molecules.

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Global analysis of community-associated methicillin-resistant Staphylococcus aureus exoproteins reveals molecules produced in vitro and during infection

Cited by 161 publications

References 60 publications

Activation of the SspA Serine Protease Zymogen of Staphylococcus aureus Proceeds through Unique Variations of a Trypsinogen-like Mechanism and Is Dependent on Both Autocatalytic and Metalloprotease-specific Processing

Activation of the SspA Serine Protease Zymogen of Staphylococcus aureus Proceeds through Unique Variations of a Trypsinogen-like Mechanism and Is Dependent on Both Autocatalytic and Metalloprotease-specific Processing

Staphylococcus aureus Metalloprotease Aureolysin Cleaves Complement C3 To Mediate Immune Evasion

Site-Specific Mutation of the Sensor Kinase GraS in Staphylococcus aureus Alters the Adaptive Response to Distinct Cationic Antimicrobial Peptides

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