Wzy-Dependent Bacterial Capsules as Potential Drug Targets

Ericsson, Daniel; Standish, Alistair J.; Kobe, Boštjan; Morona, Renato

doi:10.2174/138945012803530279

Cited by 12 publications

(9 citation statements)

References 98 publications

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“…With their critical role in the biosynthesis of CPS and EPS, the described bacterial PTPs represent a novel target for the development of antivirulence drugs [as we have discussed in detail recently (22)]. Such drugs would be expected to interrupt biosynthesis of this crucial virulence determinant, rendering the pathogen susceptible to the host's immune system (22).…”

Section: Ptps As a Target For The Development Of Novel Antivirulence mentioning

confidence: 99%

“…Such drugs would be expected to interrupt biosynthesis of this crucial virulence determinant, rendering the pathogen susceptible to the host's immune system (22). It is thought that bacteria will be less likely to develop resistance against such antivirulence drugs compared with conventional antibiotics, as antivirulence drugs do not directly kill the pathogen (83).…”

Section: Ptps As a Target For The Development Of Novel Antivirulence mentioning

confidence: 99%

“…Work has shown that in a range of bacteria, biosynthesis of secreted polysaccharides is regulated by tyrosine phosphorylation, and associated bacterial protein tyrosine phosphatases (PTPs) and kinases (BY-kinase). Given the critical role of secreted polysaccharides in virulence, these proteins represent promising targets for the development of novel antivirulence drugs (22).…”

Section: Introductionmentioning

confidence: 99%

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The Role of Bacterial Protein Tyrosine Phosphatases in the Regulation of the Biosynthesis of Secreted Polysaccharides

Standish

Morona²

2014

Antioxidants & Redox Signaling

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Significance: Tyrosine phosphorylation and associated protein tyrosine phosphatases are gaining prominence as critical mechanisms in the regulation of fundamental processes in a wide variety of bacteria. In particular, these phosphatases have been associated with the control of the biosynthesis of capsular polysaccharides and extracellular polysaccharides, critically important virulence factors for bacteria. Recent Advances: Deletion and overexpression of the phosphatases result in altered polysaccharide biosynthesis in a range of bacteria. The recent structures of associated auto-phosphorylating tyrosine kinases have suggested that the phosphatases may be critical for the cycling of the kinases between monomers and higher order oligomers. Critical Issues: Additional substrates of the phosphatases apart from cognate kinases are currently being identified. These are likely to be critical to our understanding of the mechanism by which polysaccharide biosynthesis is regulated. Future Directions: Ultimately, these protein tyrosine phosphatases are an attractive target for the development of novel antimicrobials. This is particularly the case for the polymerase and histidinol phosphatase family, which is predominantly found in bacteria. Furthermore, the determination of bacterial tyrosine phosphoproteomes will likely help to uncover the fundamental roles, mechanism, and critical importance of these phosphatases in a wide range of bacteria. Antioxid. Redox Signal. 20, 2274Signal. 20, -2289

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Section: Ptps As a Target For The Development Of Novel Antivirulence mentioning

confidence: 99%

Section: Ptps As a Target For The Development Of Novel Antivirulence mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Role of Bacterial Protein Tyrosine Phosphatases in the Regulation of the Biosynthesis of Secreted Polysaccharides

Standish

Morona²

2014

Antioxidants & Redox Signaling

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“…Since BY-kinases do not share any similarities with eukaryotic counterparts, they are considered attractive drug targets for novel antibiotics. [15][16][17] However, their characterization and inhibitor screening have both been hampered by the lack of versatile methods to monitor kinase activity. The assays for BY-kinases described to date rely on in vitro reactions using purified enzymes and radioactive 32 P-ATP.…”

Section: Introductionmentioning

confidence: 99%

Expression of Active <i>Staphylococcus aureus</i> Tyrosine Kinases in a Human Cell Line

Fukazawa

Fukuyama

Miyazaki

2019

Biological & Pharmaceutical Bulletin

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Many bacteria encode tyrosine kinases that are structurally unrelated to their eukaryotic counterparts and are termed BY-kinases. Two BY-kinases, CapB1 and CapB2, have been identified in the Staphylococcus aureus genome. Although CapB1 and CapB2 share more than 70% homology, earlier studies with purified enzymes did not find any evident kinase activity in CapB1, whereas CapB2 was autophosphorylated on a C-terminal tyrosine cluster in the presence of the kinase modulator proteins CapA1 or CapA2. For the convenient analysis of BY-kinases, we attempted to express CapB2 in an active form in a mammalian cell line. To this end, the C-terminal activation domain of CapA1 was attached to the N-terminus of CapB2, and the resulting CapA1/CT-CapB2 chimera was further fused with various tags and transfected into HEK293T cells. Immunoblotting analyses showed that when fluorescent protein tags were attached to the N-terminus, CapA1/CT-CapB2 was both expressed and tyrosine phosphorylated in HEK293T cells. Mutation of the ATPbinding lysine abrogated tyrosine phosphorylation, indicating that tyrosine phosphorylation was catalyzed by the transfected bacterial kinase and not by endogenous cellular enzymes. Unexpectedly, mutation of the C-terminal tyrosine cluster did not abolish autophosphorylation. Further analyses revealed that CapA1/CT-CapB2 phosphorylated not only itself but also the attached fluorescent protein tag. Several domains and residues important for tyrosine kinase activity were identified from the production of various mutants. We also present data that CapB1, which was previously thought to be catalytically inert, may possess intrinsic kinase activity.

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“…This has led to the investigation of bacterial protein tyrosine phosphatases and tyrosine kinases (BY kinases) as novel targets for the development of antimicrobials (2,3). Streptococcus pneumoniae is one such human pathogen for which tyrosine phosphorylation is critical.…”

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confidence: 99%

Topology of Streptococcus pneumoniae CpsC, a Polysaccharide Copolymerase and Bacterial Protein Tyrosine Kinase Adaptor Protein

2015

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In Gram-positive bacteria, tyrosine kinases are split into two proteins, the cytoplasmic tyrosine kinase and a transmembrane adaptor protein. In Streptococcus pneumoniae, this transmembrane adaptor is CpsC, with the C terminus of CpsC critical for interaction and subsequent tyrosine kinase activity of CpsD. Topology predictions suggest that CpsC has two transmembrane domains, with the N and C termini present in the cytoplasm. In order to investigate CpsC topology, we used a chromosomal hemagglutinin (HA)-tagged Cps2C protein in S. pneumoniae strain D39. Incubation of both protoplasts and membranes with carboxypeptidase B (CP-B) resulted in complete degradation of HA-Cps2C in all cases, indicating that the C terminus of Cps2C was likely extracytoplasmic and hence that the protein's topology was not as predicted. Similar results were seen with membranes from S. pneumoniae strain TIGR4, indicating that Cps4C also showed similar topology. A chromosomally encoded fusion of HA-Cps2C and Cps2D was not degraded by CP-B, suggesting that the fusion fixed the C terminus within the cytoplasm. However, capsule synthesis was unaltered by this fusion. Detection of the CpsC C terminus by flow cytometry indicated that it was extracytoplasmic in approximately 30% of cells. Interestingly, a mutant in the protein tyrosine phosphatase CpsB had a significantly greater proportion of positive cells, although this effect was independent of its phosphatase activity. Our data indicate that CpsC possesses a varied topology, with the C terminus flipping across the cytoplasmic membrane, where it interacts with CpsD in order to regulate tyrosine kinase activity.T he critical importance of bacterial tyrosine phosphorylation to the basic physiology and virulence of a wide range of pathogens is becoming increasingly more recognized (1). This has led to the investigation of bacterial protein tyrosine phosphatases and tyrosine kinases (BY kinases) as novel targets for the development of antimicrobials (2, 3). Streptococcus pneumoniae is one such human pathogen for which tyrosine phosphorylation is critical. In the pneumococcus, tyrosine phosphorylation plays an important role in regulation of the biosynthesis of the polysaccharide capsule. The capsule is considered the major virulence factor of the pneumococcus through its ability to act as an antiphagocytic factor (4), and indeed all isolates causing invasive disease are encapsulated.In recent times, we have investigated the role of a tyrosine phosphoregulatory system in the regulation of the biosynthesis of the polysaccharide capsule. The three genes responsible for this system are cotranscribed at the 5= end of the capsule locus, with all being essential for the complete encapsulation of the pneumococcus (5-8). These three genes are responsible for encoding a protein tyrosine phosphatase (CpsB) (6) that acts to dephosphorylate an autophosphorylating bacterial tyrosine kinase CpsD (BY kinase), along with the polysaccharide copolymerase protein (PCP) CpsC (7). While in Gram-negative bacteria BY k...

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Wzy-Dependent Bacterial Capsules as Potential Drug Targets

Cited by 12 publications

References 98 publications

The Role of Bacterial Protein Tyrosine Phosphatases in the Regulation of the Biosynthesis of Secreted Polysaccharides

The Role of Bacterial Protein Tyrosine Phosphatases in the Regulation of the Biosynthesis of Secreted Polysaccharides

Expression of Active <i>Staphylococcus aureus</i> Tyrosine Kinases in a Human Cell Line

Topology of Streptococcus pneumoniae CpsC, a Polysaccharide Copolymerase and Bacterial Protein Tyrosine Kinase Adaptor Protein

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