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Perez AJ, Lamanna MM, Bruce KE, Touraev MA, Page JE, Shaw SL, Tsui HCT, Winkler ME. Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae. bioRxiv 2024:2024.01.10.575112. [PMID: 38328058 PMCID: PMC10849506 DOI: 10.1101/2024.01.10.575112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed non-processive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.
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Jaroch M, Sun G, Tsui HCT, Reed C, Sun J, Jörg M, Winkler ME, Rice KC, Dziergowska A, Stich TA, Dedon PC, Dos Santos PC, de Crécy-Lagard V. Alternate routes to mnm 5s 2U synthesis in Gram-positive bacteria. J Bacteriol 2024; 206:e0045223. [PMID: 38551342 PMCID: PMC11025329 DOI: 10.1128/jb.00452-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 03/09/2024] [Indexed: 04/09/2024] Open
Abstract
The wobble bases of tRNAs that decode split codons are often heavily modified. In bacteria, tRNAGlu, Gln, Asp contains a variety of xnm5s2U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm5s2U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the conversion of cmnm5s2U to mnm5s2U. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the radical Sam superfamily was found to be involved in the synthesis of mnm5s2U in both Bacillus subtilis and Streptococcus mutans. This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm5s2U into mnm5s2U in B. subtilis. Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathway intermediates owing to regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. Although mechanistic details of these newly discovered components are not fully resolved, the occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in Nature.IMPORTANCEThe xnm5s2U modifications found in several tRNAs at the wobble base position are widespread in bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile radical SAM superfamily and is involved in the synthesis of mnm5s2U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications.
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Affiliation(s)
- Marshall Jaroch
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Guangxin Sun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | | | - Colbie Reed
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Jingjing Sun
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | - Marko Jörg
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | | | - Troy A. Stich
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Singapore-MIT Alliance for Research and Technology, CREATE Tower, Singapore
| | | | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
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De Lay NR, Verma N, Sinha D, Garrett A, Osterberg MK, Reiling S, Porter D, Giedroc DP, Winkler ME. The five homologous CiaR-controlled Ccn sRNAs of Streptococcus pneumoniae modulate Zn-resistance. bioRxiv 2024:2023.11.07.565944. [PMID: 37986909 PMCID: PMC10659304 DOI: 10.1101/2023.11.07.565944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Zinc is a vital transition metal for Streptococcus pneumoniae, but is deadly at high concentrations. In S. pneumoniae, elevated intracellular free Zn levels result in mis-metallation of key Mn-dependent metabolic and superoxide detoxifying enzymes resulting in Zn intoxication. Here, we report our identification and characterization of the function of the five homologous, CiaRH-regulated Ccn sRNAs in controlling S. pneumoniae virulence and metal homeostasis. We show that deletion of all five ccn genes (ccnA, ccnB, ccnC, ccnD, and ccnE) from S. pneumoniae strains D39 (serotype 2) and TIGR4 (serotype 4) causes Zn hypersensitivity and an attenuation of virulence in a murine invasive pneumonia model. We provide evidence that bioavailable Zn disproportionately increases in S. pneumoniae strains lacking the five ccn genes. Consistent with a response to Zn intoxication or relatively high intracellular free Zn levels, expression of genes encoding the CzcD Zn exporter and the Mn-independent ribonucleotide reductase, NrdD-NrdG, were increased in the ΔccnABCDE mutant relative to its isogenic ccn+ parent strain. The growth inhibition by Zn that occurs as the result of loss of the ccn genes is rescued by supplementation with Mn or Oxyrase™, a reagent that removes dissolved oxygen. Lastly, we found that the Zn-dependent growth inhibition of the ΔccnABCDE strain was not altered by deletion of sodA, whereas the ccn+ ΔsodA strain phenocopied the ΔccnABCDE strain. Overall, our results indicate that the Ccn sRNAs have a crucial role in preventing Zn intoxication in S. pneumoniae.
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Affiliation(s)
- Nicholas R. De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Nidhi Verma
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Dhriti Sinha
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Abigail Garrett
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405
| | | | - Spencer Reiling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Daisy Porter
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, Bloomington, Indiana 47405
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405
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Jaroch M, Sun G, Tsui HCT, Reed C, Sun J, Jörg M, Winkler ME, Rice KC, Stich TA, Dedon PC, Dos Santos PC, de Crécy-Lagard V. Alternate routes to mnm 5 s 2 U synthesis in Gram-positive bacteria. bioRxiv 2023:2023.12.21.572861. [PMID: 38187551 PMCID: PMC10769405 DOI: 10.1101/2023.12.21.572861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The wobble bases of tRNAs that decode split codons are often heavily modified. In Bacteria tRNA Glu, Gln, Asp contain a variety of xnm 5 s 2 U derivatives. The synthesis pathway for these modifications is complex and fully elucidated only in a handful of organisms, including the Gram-negative Escherichia coli K12 model. Despite the ubiquitous presence of mnm 5 s 2 U modification, genomic analysis shows the absence of mnmC orthologous genes, suggesting the occurrence of alternate biosynthetic schemes for the installation of this modification. Using a combination of comparative genomics and genetic studies, a member of the YtqA subgroup of the Radical Sam superfamily was found to be involved in the synthesis of mnm 5 s 2 U in both Bacillus subtilis and Streptococcus mutans . This protein, renamed MnmL, is encoded in an operon with the recently discovered MnmM methylase involved in the methylation of the pathway intermediate nm 5 s 2 U into mnm 5 s 2 U in B. subtilis . Analysis of tRNA modifications of both S. mutans and Streptococcus pneumoniae shows that growth conditions and genetic backgrounds influence the ratios of pathways intermediates in regulatory loops that are not yet understood. The MnmLM pathway is widespread along the bacterial tree, with some phyla, such as Bacilli, relying exclusively on these two enzymes. The occurrence of fusion proteins, alternate arrangements of biosynthetic components, and loss of biosynthetic branches provide examples of biosynthetic diversity to retain a conserved tRNA modification in nature. Importance The xnm 5 s 2 U modifications found in several tRNAs at the wobble base position are widespread in Bacteria where they have an important role in decoding efficiency and accuracy. This work identifies a novel enzyme (MnmL) that is a member of a subgroup of the very versatile Radical SAM superfamily and is involved in the synthesis of mnm 5 s 2 U in several Gram-positive bacteria, including human pathogens. This is another novel example of a non-orthologous displacement in the field of tRNA modification synthesis, showing how different solutions evolve to retain U34 tRNA modifications.
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Winkler ME, Joseph M, Tsui HCT. Secrets of getting started: Regulation of the first committed step of peptidoglycan synthesis by protein phosphorylation in Enterococcus and other Gram-positive bacteria. Mol Microbiol 2023; 120:805-810. [PMID: 38012814 PMCID: PMC10834034 DOI: 10.1111/mmi.15204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 11/18/2023] [Accepted: 11/19/2023] [Indexed: 11/29/2023]
Abstract
Regulation of the first committed step of peptidoglycan precursor synthesis by MurA-enzyme homologs has recently taken center stage in many different bacteria. In different low-GC Gram-positive bacteria, regulation of this step has been shown to be regulated by phosphorylation of homologs of the IreB/ReoM regulatory protein by PASTA-domain Ser/Thr-protein kinases. In this issue, Mascari, Little, and Kristich determine this regulatory pathway and its links to resistance to cephalosporin β-lactam antibiotics in the major human pathogen, Enterococcus faecalis (Efa). Unbiased genetic selections identified MurAA (MurA-family homolog) as the downstream target of IreB regulation in the absence of the IreK Ser/Thr-protein kinase. Physiological and biochemical approaches, including determination of MICs to ceftriaxone, Western blotting of MurAA cellular amounts, isotope incorporation into peptidoglycan sacculi, and thermal-shift binding assays of purified proteins, demonstrated that unphosphorylated IreB, together with proteins MurAB (MurZ-family homolog), and ReoY(Efa) negatively regulate MurAA stability and cellular amount by the ClpCP protease. Importantly, this paper supports the idea that ceftriaxone stimulates phosphorylation of IreB, which leads to increased cellular MurAA amount and precursor pathway flux required for E. faecalis cephalosporin resistance. Overall, findings in this paper significantly contribute to understanding variations of this central regulatory pathway in other low-GC Gram-positive bacteria.
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Affiliation(s)
- Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Merrin Joseph
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Ho-Ching T. Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Negative regulation of MurZ and MurA underlies the essentiality of GpsB- and StkP-mediated protein phosphorylation in Streptococcus pneumoniae D39. Mol Microbiol 2023; 120:351-383. [PMID: 37452010 PMCID: PMC10530524 DOI: 10.1111/mmi.15122] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP(Spn) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress ΔgpsB or ΔstkP. These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overproduction of MurZ caused by ΔkhpAB mutations suppressed ΔgpsB or ΔstkP phenotypes to varying extents. ΔgpsB and ΔstkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, ΔgpsB and ΔstkP were not suppressed by ΔclpCP, which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB(Spn), is the only essential requirement for StkP-mediated protein phosphorylation in exponentially growing D39 pneumococcal cells.
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Affiliation(s)
| | - Merrin Joseph
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Jiaqi J. Zheng
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Amilcar J. Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Irfan Manzoor
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Britta E. Rued
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - John D. Richardson
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Pavel Branny
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Linda Doubravová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Orietta Massidda
- Department of Cellular, Computational, and Integrative Biology, University of Trento, Italy
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
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Tsui HCT, Joseph M, Zheng JJ, Perez AJ, Manzoor I, Rued BE, Richardson JD, Branny P, Doubravová L, Massidda O, Winkler ME. Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation in Streptococcus pneumoniae D39. bioRxiv 2023:2023.03.26.534294. [PMID: 37034771 PMCID: PMC10081211 DOI: 10.1101/2023.03.26.534294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn ) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP( Spn ) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress Δ gpsB or Δ stkP . These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overexpression of MurZ caused by Δ khpAB mutations suppressed Δ gpsB or Δ stkP phenotypes to varying extents. Δ gpsB and Δ stkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, Δ gpsB and Δ stkP were not suppressed by Δ clpCP , which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB( Spn ), is the only essential requirement for protein phosphorylation in exponentially growing D39 pneumococcal cells.
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Lamanna MM, Manzoor I, Joseph M, Ye ZA, Benedet M, Zanardi A, Ren Z, Wang X, Massidda O, Tsui HT, Winkler ME. Roles of RodZ and class A PBP1b in the assembly and regulation of the peripheral peptidoglycan elongasome in ovoid-shaped cells of Streptococcus pneumoniae D39. Mol Microbiol 2022; 118:336-368. [PMID: 36001060 PMCID: PMC9804626 DOI: 10.1111/mmi.14969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 01/17/2023]
Abstract
RodZ of rod-shaped bacteria functions to link MreB filaments to the Rod peptidoglycan (PG) synthase complex that moves circumferentially perpendicular to the long cell axis, creating hoop-like sidewall PG. Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus; Spn) that lack MreB, use a different modality for peripheral PG elongation that emanates from the midcell of dividing cells. Yet, S. pneumoniae encodes a RodZ homolog similar to RodZ in rod-shaped bacteria. We show here that the helix-turn-helix and transmembrane domains of RodZ(Spn) are essential for growth at 37°C. ΔrodZ mutations are suppressed by Δpbp1a, mpgA(Y488D), and ΔkhpA mutations that suppress ΔmreC, but not ΔcozE. Consistent with a role in PG elongation, RodZ(Spn) co-localizes with MreC and aPBP1a throughout the cell cycle and forms complexes and interacts with PG elongasome proteins and regulators. Depletion of RodZ(Spn) results in aberrantly shaped, non-growing cells and mislocalization of elongasome proteins MreC, PBP2b, and RodA. Moreover, Tn-seq reveals that RodZ(Spn), but not MreCD(Spn), displays a specific synthetic-viable genetic relationship with aPBP1b, whose function is unknown. We conclude that RodZ(Spn) acts as a scaffolding protein required for elongasome assembly and function and that aPBP1b, like aPBP1a, plays a role in elongasome regulation and possibly peripheral PG synthesis.
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Affiliation(s)
- Melissa M. Lamanna
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Irfan Manzoor
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Merrin Joseph
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Ziyun A. Ye
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Mattia Benedet
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Alessia Zanardi
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Zhongqing Ren
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Xindan Wang
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Orietta Massidda
- Department of Cellular, Computational and Integrative Biology (CIBIO)University of TrentoTrentoItaly
| | - Ho‐Ching T. Tsui
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
| | - Malcolm E. Winkler
- Department of BiologyIndiana University BloomingtonBloomingtonIndianaUSA
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Zhang Y, Martin JE, Edmonds KA, Winkler ME, Giedroc DP. SifR is an Rrf2-family quinone sensor associated with catechol iron uptake in Streptococcus pneumoniae D39. J Biol Chem 2022; 298:102046. [PMID: 35597283 PMCID: PMC9218516 DOI: 10.1016/j.jbc.2022.102046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 01/15/2023] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a Gram-positive commensal and human respiratory pathogen. How this bacterium satisfies its nutritional iron (Fe) requirement in the context of endogenously produced hydrogen peroxide is not well understood. Here, we characterize a novel virulence-associated Rrf2-family transcriptional repressor that we term SifR (streptococcal IscR-like family transcriptional repressor) encoded by spd_1448 and conserved in Streptococci. Global transcriptomic analysis of a ΔsifR strain defines the SifR regulon as genes encoding a candidate catechol dioxygenase CatE, an uncharacterized oxidoreductase YwnB, a candidate flavin-dependent ferric reductase YhdA, a candidate heme-based ferric reductase domain-containing protein and the Piu (pneumococcus iron uptake) Fe transporter (piuBCDA). Previous work established that membrane-anchored PiuA binds FeIII-bis-catechol or monocatechol complexes with high affinity, including the human catecholamine stress hormone, norepinephrine. We demonstrate that SifR senses quinone via a single conserved cysteine that represses its regulon when in the reduced form. Upon reaction with catechol-derived quinones, we show that SifR dissociates from the DNA leading to regulon derepression, allowing the pneumococcus to access a catechol-derived source of Fe while minimizing reactive electrophile stress induced by quinones. Consistent with this model, we show that CatE is an FeII-dependent 2,3-catechol dioxygenase with broad substrate specificity, YwnB is an NAD(P)H-dependent quinone reductase capable of reducing the oxidized and cyclized norepinephrine, adrenochrome, and YhdA is capable of reducing a number of FeIII complexes, including PiuA-binding transport substrates. These findings are consistent with a model where FeIII-catechol complexes serve as significant nutritional Fe sources in the host.
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Affiliation(s)
- Yifan Zhang
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA
| | - Julia E Martin
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
| | | | - Malcolm E Winkler
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA; Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA; Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA.
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Perez AJ, Villicana JB, Tsui HCT, Danforth ML, Benedet M, Massidda O, Winkler ME. FtsZ-Ring Regulation and Cell Division Are Mediated by Essential EzrA and Accessory Proteins ZapA and ZapJ in Streptococcus pneumoniae. Front Microbiol 2021; 12:780864. [PMID: 34938281 PMCID: PMC8687745 DOI: 10.3389/fmicb.2021.780864] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 10/22/2021] [Indexed: 12/02/2022] Open
Abstract
The bacterial FtsZ-ring initiates division by recruiting a large repertoire of proteins (the divisome; Z-ring) needed for septation and separation of cells. Although FtsZ is essential and its role as the main orchestrator of cell division is conserved in most eubacteria, the regulators of Z-ring presence and positioning are not universal. This study characterizes factors that regulate divisome presence and placement in the ovoid-shaped pathogen, Streptococcus pneumoniae (Spn), focusing on FtsZ, EzrA, SepF, ZapA, and ZapJ, which is reported here as a partner of ZapA. Epi-fluorescence microscopy (EFm) and high-resolution microscopy experiments showed that FtsZ and EzrA co-localize during the entire Spn cell cycle, whereas ZapA and ZapJ are late-arriving divisome proteins. Depletion and conditional mutants demonstrate that EzrA is essential in Spn and required for normal cell growth, size, shape homeostasis, and chromosome segregation. Moreover, EzrA(Spn) is required for midcell placement of FtsZ-rings and PG synthesis. Notably, overexpression of EzrA leads to the appearance of extra Z-rings in Spn. Together, these observations support a role for EzrA as a positive regulator of FtsZ-ring formation in Spn. Conversely, FtsZ is required for EzrA recruitment to equatorial rings and for the organization of PG synthesis. In contrast to EzrA depletion, which causes a bacteriostatic phenotype in Spn, depletion of FtsZ results in enlarged spherical cells that are subject to LytA-dependent autolysis. Co-immunoprecipitation and bacterial two-hybrid assays show that EzrA(Spn) is in complexes with FtsZ, Z-ring regulators (FtsA, SepF, ZapA, MapZ), division proteins (FtsK, StkP), and proteins that mediate peptidoglycan synthesis (GpsB, aPBP1a), consistent with a role for EzrA at the interface of cell division and PG synthesis. In contrast to the essentiality of FtsZ and EzrA, ZapA and SepF have accessory roles in regulating pneumococcal physiology. We further show that ZapA interacts with a non-ZapB homolog, named here as ZapJ, which is conserved in Streptococcus species. The absence of the accessory proteins, ZapA, ZapJ, and SepF, exacerbates growth defects when EzrA is depleted or MapZ is deleted. Taken together, these results provide new information about the spatially and temporally distinct proteins that regulate FtsZ-ring organization and cell division in Spn.
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Affiliation(s)
- Amilcar J Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Jesus Bazan Villicana
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Ho-Ching T Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Madeline L Danforth
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Mattia Benedet
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Orietta Massidda
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
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11
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Briggs NS, Bruce KE, Naskar S, Winkler ME, Roper DI. The Pneumococcal Divisome: Dynamic Control of Streptococcus pneumoniae Cell Division. Front Microbiol 2021; 12:737396. [PMID: 34737730 PMCID: PMC8563077 DOI: 10.3389/fmicb.2021.737396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022] Open
Abstract
Cell division in Streptococcus pneumoniae (pneumococcus) is performed and regulated by a protein complex consisting of at least 14 different protein elements; known as the divisome. Recent findings have advanced our understanding of the molecular events surrounding this process and have provided new understanding of the mechanisms that occur during the division of pneumococcus. This review will provide an overview of the key protein complexes and how they are involved in cell division. We will discuss the interaction of proteins in the divisome complex that underpin the control mechanisms for cell division and cell wall synthesis and remodelling that are required in S. pneumoniae, including the involvement of virulence factors and capsular polysaccharides.
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Affiliation(s)
- Nicholas S. Briggs
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Kevin E. Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Souvik Naskar
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - David I. Roper
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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12
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Abstract
Extracellular peptidoglycan-linked polysaccharide modifications mediate cell morphology, division, and autolysis in some Gram-positive bacterial pathogens. A new study shows that the degree and location of a specific modification controls peptidoglycan hydrolysis and placement of the axis of cell division.
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13
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McCausland JW, Yang X, Squyres GR, Lyu Z, Bruce KE, Lamanna MM, Söderström B, Garner EC, Winkler ME, Xiao J, Liu J. Treadmilling FtsZ polymers drive the directional movement of sPG-synthesis enzymes via a Brownian ratchet mechanism. Nat Commun 2021; 12:609. [PMID: 33504807 PMCID: PMC7840769 DOI: 10.1038/s41467-020-20873-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/15/2020] [Indexed: 01/30/2023] Open
Abstract
The FtsZ protein is a central component of the bacterial cell division machinery. It polymerizes at mid-cell and recruits more than 30 proteins to assemble into a macromolecular complex to direct cell wall constriction. FtsZ polymers exhibit treadmilling dynamics, driving the processive movement of enzymes that synthesize septal peptidoglycan (sPG). Here, we combine theoretical modelling with single-molecule imaging of live bacterial cells to show that FtsZ's treadmilling drives the directional movement of sPG enzymes via a Brownian ratchet mechanism. The processivity of the directional movement depends on the binding potential between FtsZ and the sPG enzyme, and on a balance between the enzyme's diffusion and FtsZ's treadmilling speed. We propose that this interplay may provide a mechanism to control the spatiotemporal distribution of active sPG enzymes, explaining the distinct roles of FtsZ treadmilling in modulating cell wall constriction rate observed in different bacteria.
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Affiliation(s)
- Joshua W McCausland
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Xinxing Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Georgia R Squyres
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Zhixin Lyu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Kevin E Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Melissa M Lamanna
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Bill Söderström
- The ithree Institute, University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
| | - Jian Liu
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
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14
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Perez AJ, Boersma MJ, Bruce KE, Lamanna MM, Shaw SL, Tsui HCT, Taguchi A, Carlson EE, VanNieuwenhze MS, Winkler ME. Organization of peptidoglycan synthesis in nodes and separate rings at different stages of cell division of Streptococcus pneumoniae. Mol Microbiol 2020; 115:1152-1169. [PMID: 33269494 DOI: 10.1111/mmi.14659] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 12/15/2022]
Abstract
Bacterial peptidoglycan (PG) synthesis requires strict spatiotemporal organization to reproduce specific cell shapes. In ovoid-shaped Streptococcus pneumoniae (Spn), septal and peripheral (elongation) PG synthesis occur simultaneously at midcell. To uncover the organization of proteins and activities that carry out these two modes of PG synthesis, we examined Spn cells vertically oriented onto their poles to image the division plane at the high lateral resolution of 3D-SIM (structured-illumination microscopy). Labeling with fluorescent D-amino acids (FDAA) showed that areas of new transpeptidase (TP) activity catalyzed by penicillin-binding proteins (PBPs) separate into a pair of concentric rings early in division, representing peripheral PG (pPG) synthesis (outer ring) and the leading-edge (inner ring) of septal PG (sPG) synthesis. Fluorescently tagged PBP2x or FtsZ locate primarily to the inner FDAA-marked ring, whereas PBP2b and FtsX remain in the outer ring, suggesting roles in sPG or pPG synthesis, respectively. Pulses of FDAA labeling revealed an arrangement of separate regularly spaced "nodes" of TP activity around the division site of predivisional cells. Tagged PBP2x, PBP2b, and FtsX proteins also exhibited nodal patterns with spacing comparable to that of FDAA labeling. Together, these results reveal new aspects of spatially ordered PG synthesis in ovococcal bacteria during cell division.
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Affiliation(s)
- Amilcar J Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Michael J Boersma
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Kevin E Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Melissa M Lamanna
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Sidney L Shaw
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Ho-Ching T Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
| | - Atsushi Taguchi
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | | | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, USA
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15
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Sharifzadeh S, Brown NW, Shirley JD, Bruce KE, Winkler ME, Carlson EE. Chemical tools for selective activity profiling of bacterial penicillin-binding proteins. Methods Enzymol 2020; 638:27-55. [PMID: 32416917 DOI: 10.1016/bs.mie.2020.02.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Penicillin-binding proteins (PBPs) are membrane-associated proteins involved in the biosynthesis of peptidoglycan (PG), the main component of bacterial cell walls. These proteins were discovered and named for their affinity to bind the β-lactam antibiotic penicillin. The importance of the PBPs has long been appreciated; however, specific roles of individual family members in each bacterial strain, as well as their protein-protein interactions, are yet to be understood. The apparent functional redundancy of the 4-18 PBPs that most eubacteria possess makes determination of their individual roles difficult. Existing techniques to study PBPs are not ideal because they do not directly visualize protein activity and can suffer from artifacts and perturbations of native PBP function. Therefore, development of new methods for studying the roles of individual PBPs in cell wall synthesis is required. We recently generated a library of fluorescent chemical probes containing a β-lactone scaffold that specifically targets the PBPs, enabling the visualization of their catalytic activity. Herein, we describe a general protocol to label and detect the activity of individual PBPs in Streptococcus pneumoniae using our fluorescent β-lactone probes.
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Affiliation(s)
- Shabnam Sharifzadeh
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Nathaniel W Brown
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Kevin E Bruce
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States.
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16
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Martin JE, Le MT, Bhattarai N, Capdevila DA, Shen J, Winkler ME, Giedroc DP. A Mn-sensing riboswitch activates expression of a Mn2+/Ca2+ ATPase transporter in Streptococcus. Nucleic Acids Res 2020; 47:6885-6899. [PMID: 31165873 PMCID: PMC6649816 DOI: 10.1093/nar/gkz494] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/08/2019] [Accepted: 05/31/2019] [Indexed: 12/27/2022] Open
Abstract
Maintaining manganese (Mn) homeostasis is important for the virulence of numerous bacteria. In the human respiratory pathogen Streptococcus pneumoniae, the Mn-specific importer PsaBCA, exporter MntE, and transcriptional regulator PsaR establish Mn homeostasis. In other bacteria, Mn homeostasis is controlled by yybP-ykoY family riboswitches. Here, we characterize a yybP-ykoY family riboswitch upstream of the mgtA gene encoding a PII-type ATPase in S. pneumoniae, suggested previously to function in Ca2+ efflux. We show that the mgtA riboswitch aptamer domain adopts a canonical yybP-ykoY structure containing a three-way junction that is compacted in the presence of Ca2+ or Mn2+ at a physiological Mg2+ concentration. Although Ca2+ binds to the RNA aptamer with higher affinity than Mn2+, in vitro activation of transcription read-through of mgtA by Mn2+ is much greater than by Ca2+. Consistent with this result, mgtA mRNA and protein levels increase ≈5-fold during cellular Mn stress, but only in genetic backgrounds of S. pneumoniae and Bacillus subtilis that exhibit Mn2+ sensitivity, revealing that this riboswitch functions as a failsafe ‘on’ signal to prevent Mn2+ toxicity in the presence of high cellular Mn2+. In addition, our results suggest that the S. pneumoniae yybP-ykoY riboswitch functions to regulate Ca2+ efflux under these conditions.
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Affiliation(s)
- Julia E Martin
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | - My T Le
- Department of Cell Biology, Faculty of Biological Sciences, Vietnam National University, Hanoi, Vietnam
| | - Nabin Bhattarai
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | | | - Jiangchuan Shen
- Department of Cellular and Molecular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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17
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Kocaoglu O, Calvo RA, Sham LT, Cozy LM, Lanning BR, Francis S, Winkler ME, Kearns DB, Carlson EE. Selective Penicillin-Binding Protein Imaging Probes Reveal Substructure in Bacterial Cell Division. ACS Chem Biol 2019; 14:1672. [PMID: 31265231 DOI: 10.1021/acschembio.9b00459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Abstract
DNA uptake by natural competence is a central process underlying the genetic plasticity, biology, and virulence of the human respiratory opportunistic pathogen Streptococcus pneumoniae A study reported in this issue (J. Slager, R. Aprianto, and J.-W. Veening, J. Bacteriol. 201:e00780-18, https://doi.org/10.1128/JB.00780-18) combined deep-genome annotation and high-resolution transcriptome analyses to considerably extend the previous model of temporal regulation of competence at the operon and component gene levels. That extended study also provides a playbook for updating, refining, and extending genomic data sets and making them publicly available.
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Affiliation(s)
- Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Donald A Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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19
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Cleverley RM, Rutter ZJ, Rismondo J, Corona F, Tsui HCT, Alatawi FA, Daniel RA, Halbedel S, Massidda O, Winkler ME, Lewis RJ. The cell cycle regulator GpsB functions as cytosolic adaptor for multiple cell wall enzymes. Nat Commun 2019; 10:261. [PMID: 30651563 PMCID: PMC6335420 DOI: 10.1038/s41467-018-08056-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 12/07/2018] [Indexed: 01/01/2023] Open
Abstract
Bacterial growth and cell division requires precise spatiotemporal regulation of the synthesis and remodelling of the peptidoglycan layer that surrounds the cytoplasmic membrane. GpsB is a cytosolic protein that affects cell wall synthesis by binding cytoplasmic mini-domains of peptidoglycan synthases to ensure their correct subcellular localisation. Here, we describe critical structural features for the interaction of GpsB with peptidoglycan synthases from three bacterial species (Bacillus subtilis, Listeria monocytogenes and Streptococcus pneumoniae) and suggest their importance for cell wall growth and viability in L. monocytogenes and S. pneumoniae. We use these structural motifs to identify novel partners of GpsB in B. subtilis and extend the members of the GpsB interactome in all three bacterial species. Our results support that GpsB functions as an adaptor protein that mediates the interaction between membrane proteins, scaffolding proteins, signalling proteins and enzymes to generate larger protein complexes at specific sites in a bacterial cell cycle-dependent manner.
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Affiliation(s)
- Robert M Cleverley
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
| | - Zoe J Rutter
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
| | - Jeanine Rismondo
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Federico Corona
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | | | - Fuad A Alatawi
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | - Richard A Daniel
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4AX, UK
| | - Sven Halbedel
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
| | - Orietta Massidda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
- Department CIBIO, University of Trento, via Sommarive 9, 38123, Povo, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Richard J Lewis
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK.
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20
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Sharifzadeh S, Boersma MJ, Kocaoglu O, Shokri A, Brown CL, Shirley JD, Winkler ME, Carlson EE. Novel Electrophilic Scaffold for Imaging of Essential Penicillin-Binding Proteins in Streptococcus pneumoniae. ACS Chem Biol 2017; 12:2849-2857. [PMID: 28990753 DOI: 10.1021/acschembio.7b00614] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidoglycan (PG) is a mesh-like heteropolymer made up of glycan chains cross-linked by short peptides and is the major scaffold of eubacterial cell walls, determining cell shape, size, and chaining. This structure, which is required for growth and survival, is located outside of the cytoplasmic membrane of bacterial cells, making it highly accessible to antibiotics. Penicillin-binding proteins (PBPs) are essential for construction of PG and perform transglycosylase activities to generate the glycan strands and transpeptidation to cross-link the appended peptides. The β-lactam antibiotics, which are among the most clinically effective antibiotics for the treatment of bacterial infections, inhibit PBP transpeptidation, ultimately leading to cell lysis. Despite this importance, the discrete functions of individual PBP homologues have been difficult to determine. These major gaps in understanding of PBP activation and macromolecular interactions largely result from a lack of tools to assess the functional state of specific PBPs in bacterial cells. We have identified β-lactones as a privileged scaffold for the generation of PBP-selective probes and utilized these compounds for imaging of the essential proteins, PBP2x and PBP2b, in Streptococcus pneumoniae. We demonstrated that while PBP2b activity is restricted to a ring surrounding the division sites, PBP2x activity is present both at the septal center and at the surrounding ring. These spatially separate regions of PBP2x activity could not be detected by previous activity-based approaches, which highlights a critical strength of our PBP-selective imaging strategy.
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Affiliation(s)
- Shabnam Sharifzadeh
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Michael J. Boersma
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Ozden Kocaoglu
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Alireza Shokri
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Clayton L. Brown
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Joshua D. Shirley
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Malcolm E. Winkler
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Erin E. Carlson
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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21
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Zheng JJ, Perez AJ, Tsui HCT, Massidda O, Winkler ME. Absence of the KhpA and KhpB (JAG/EloR) RNA-binding proteins suppresses the requirement for PBP2b by overproduction of FtsA in Streptococcus pneumoniae D39. Mol Microbiol 2017; 106:793-814. [PMID: 28941257 DOI: 10.1111/mmi.13847] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2017] [Indexed: 12/11/2022]
Abstract
Suppressor mutations were isolated that obviate the requirement for essential PBP2b in peripheral elongation of peptidoglycan from the midcells of dividing Streptococcus pneumoniae D39 background cells. One suppressor was in a gene encoding a single KH-domain protein (KhpA). ΔkhpA suppresses deletions in most, but not all (mltG), genes involved in peripheral PG synthesis and in the gpsB regulatory gene. ΔkhpA mutations reduce growth rate, decrease cell size, minimally affect shape and induce expression of the WalRK cell-wall stress regulon. Reciprocal co-immunoprecipitations show that KhpA forms a complex in cells with another KH-domain protein (KhpB/JAG/EloR). ΔkhpA and ΔkhpB mutants phenocopy each other exactly, consistent with a direct interaction. RNA-immunoprecipitation showed that KhpA/KhpB bind an overlapping set of RNAs in cells. Phosphorylation of KhpB reported previously does not affect KhpB function in the D39 progenitor background. A chromosome duplication implicated FtsA overproduction in Δpbp2b suppression. We show that cellular FtsA concentration is negatively regulated by KhpA/B at the post-transcriptional level and that FtsA overproduction is necessary and sufficient for suppression of Δpbp2b. However, increased FtsA only partially accounts for the phenotypes of ΔkhpA mutants. Together, these results suggest that multimeric KhpA/B may function as a pleiotropic RNA chaperone controlling pneumococcal cell division.
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Affiliation(s)
- Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Amilcar J Perez
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Ho-Ching Tiffany Tsui
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
| | - Orietta Massidda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, 09100 Cagliari, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington (IUB), Bloomington, IN 47405, USA
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22
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Martin JE, Edmonds KA, Bruce KE, Campanello GC, Eijkelkamp BA, Brazel EB, McDevitt CA, Winkler ME, Giedroc DP. The zinc efflux activator SczA protects Streptococcus pneumoniae serotype 2 D39 from intracellular zinc toxicity. Mol Microbiol 2017; 104:636-651. [PMID: 28249108 DOI: 10.1111/mmi.13654] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2017] [Indexed: 12/19/2022]
Abstract
Zinc is an essential trace element that serves as a catalytic cofactor in metalloenzymes and a structural element in proteins involved in general metabolism and cellular defenses of pathogenic bacteria. Despite its importance, high zinc levels can impair cellular processes, inhibiting growth of many pathogenic bacteria, including the major respiratory pathogen Streptococcus pneumoniae. Zinc intoxication is prevented in S. pneumoniae by expression of the zinc exporter CzcD, whose expression is activated by the novel TetR-family transcriptional zinc-sensing regulator SczA. How zinc bioavailability triggers activation of SczA is unknown. It is shown here through functional studies in S. pneumoniae that an unannotated homodimeric TetR from S. agalactiae (PDB 3KKC) is the bona fide zinc efflux regulator SczA, and binds two zinc ions per protomer. Mutagenesis analysis reveals two metal binding sites, termed A and B, located on opposite sides of the SczA C-terminal regulatory domain. In vivo, the A- and B-site SczA mutant variants impact S. pneumoniae resistance to zinc toxicity and survival in infected macrophages. A model is proposed for S. pneumoniae SczA function in which both A- and B-sites were required for transcriptional activation of czcD expression, with the A-site serving as the evolutionarily conserved intracellular sensing site in SczAs.
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Affiliation(s)
- Julia E Martin
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7005, USA
| | - Katherine A Edmonds
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7005, USA
| | - Kevin E Bruce
- Department of Biology, Indiana University, Bloomington, IN, 47405-7005, USA
| | | | - Bart A Eijkelkamp
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, SA, 5005, Australia
| | - Erin B Brazel
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, SA, 5005, Australia
| | - Christopher A McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, SA, 5005, Australia
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, 47405-7005, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7005, USA
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23
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Martin JE, Lisher JP, Winkler ME, Giedroc DP. Perturbation of manganese metabolism disrupts cell division in Streptococcus pneumoniae. Mol Microbiol 2017; 104:334-348. [PMID: 28127804 DOI: 10.1111/mmi.13630] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2017] [Indexed: 12/30/2022]
Abstract
Manganese (Mn) is an essential micronutrient and required cofactor in bacteria. Despite its importance, excess Mn can impair bacterial growth, the mechanism of which remains largely unexplored. Here, we show that proper Mn homeostasis is critical for cellular growth of the major human respiratory pathogen Streptococcus pneumoniae. Perturbations in Mn homeostasis genes, psaBCA, encoding the Mn importer, and mntE, encoding the Mn exporter, lead to Mn sensitivity during aerobiosis. Mn-stressed cells accumulate iron and copper, in addition to Mn. Impaired growth is a direct result of Mn toxicity and does not result from iron-mediated Fenton chemistry, since cells remain sensitive to Mn during anaerobiosis or when hydrogen peroxide biogenesis is significantly reduced. Mn-stressed cells are significantly elongated, whereas Mn-limitation imposed by zinc addition leads to cell shortening. We show that Mn accumulation promotes aberrant dephosphorylation of cell division proteins via hyperactivation of the Mn-dependent protein phosphatase PhpP, a key enzyme involved in the regulation of cell division. We discuss a mechanism by which cellular Mn:Zn ratios dictate PhpP specific activity thereby regulating pneumococcal cell division. We propose that Mn-metalloenzymes are particularly susceptible to hyperactivation or mismetallation, suggesting the need for exquisite cellular control of Mn-dependent metabolic processes.
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Affiliation(s)
- Julia E Martin
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA
| | - John P Lisher
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA.,Graduate Program in Biochemistry Indiana University, Bloomington, IN, 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN, 47405-7102, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
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24
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Rued BE, Zheng JJ, Mura A, Tsui HCT, Boersma MJ, Mazny JL, Corona F, Perez AJ, Fadda D, Doubravová L, Buriánková K, Branny P, Massidda O, Winkler ME. Suppression and synthetic-lethal genetic relationships of ΔgpsB mutations indicate that GpsB mediates protein phosphorylation and penicillin-binding protein interactions in Streptococcus pneumoniae D39. Mol Microbiol 2017; 103:931-957. [PMID: 28010038 DOI: 10.1111/mmi.13613] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2016] [Indexed: 01/06/2023]
Abstract
GpsB regulatory protein and StkP protein kinase have been proposed as molecular switches that balance septal and peripheral (side-wall like) peptidoglycan (PG) synthesis in Streptococcus pneumoniae (pneumococcus); yet, mechanisms of this switching remain unknown. We report that ΔdivIVA mutations are not epistatic to ΔgpsB division-protein mutations in progenitor D39 and related genetic backgrounds; nor is GpsB required for StkP localization or FDAA labeling at septal division rings. However, we confirm that reduction of GpsB amount leads to decreased protein phosphorylation by StkP and report that the essentiality of ΔgpsB mutations is suppressed by inactivation of PhpP protein phosphatase, which concomitantly restores protein phosphorylation levels. ΔgpsB mutations are also suppressed by other classes of mutations, including one that eliminates protein phosphorylation and may alter division. Moreover, ΔgpsB mutations are synthetically lethal with Δpbp1a, but not Δpbp2a or Δpbp1b mutations, suggesting GpsB activation of PBP2a activity. Consistent with this result, co-IP experiments showed that GpsB complexes with EzrA, StkP, PBP2a, PBP2b and MreC in pneumococcal cells. Furthermore, depletion of GpsB prevents PBP2x migration to septal centers. These results support a model in which GpsB negatively regulates peripheral PG synthesis by PBP2b and positively regulates septal ring closure through its interactions with StkP-PBP2x.
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Affiliation(s)
- Britta E Rued
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Andrea Mura
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy.,Cell and Molecular Microbiology Division, Institute of Microbiology, v.v.i, Academy of Sciences of the Czech Republic, Prague 4, 142 20, Czech Republic
| | - Ho-Ching T Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Michael J Boersma
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Jeffrey L Mazny
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Federico Corona
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
| | - Amilcar J Perez
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
| | - Daniela Fadda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
| | - Linda Doubravová
- Cell and Molecular Microbiology Division, Institute of Microbiology, v.v.i, Academy of Sciences of the Czech Republic, Prague 4, 142 20, Czech Republic
| | - Karolína Buriánková
- Cell and Molecular Microbiology Division, Institute of Microbiology, v.v.i, Academy of Sciences of the Czech Republic, Prague 4, 142 20, Czech Republic
| | - Pavel Branny
- Cell and Molecular Microbiology Division, Institute of Microbiology, v.v.i, Academy of Sciences of the Czech Republic, Prague 4, 142 20, Czech Republic
| | - Orietta Massidda
- Dipartimento di Scienze Chirurgiche, Università di Cagliari, Cagliari, 09100, Italy
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, USA
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25
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Zheng JJ, Sinha D, Wayne KJ, Winkler ME. Physiological Roles of the Dual Phosphate Transporter Systems in Low and High Phosphate Conditions and in Capsule Maintenance of Streptococcus pneumoniae D39. Front Cell Infect Microbiol 2016; 6:63. [PMID: 27379215 PMCID: PMC4913102 DOI: 10.3389/fcimb.2016.00063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/27/2016] [Indexed: 12/28/2022] Open
Abstract
Unlike most bacteria, Streptococcus pneumoniae (pneumococcus) has two evolutionarily distinct ABC transporters (Pst1 and Pst2) for inorganic phosphate (Pi) uptake. The genes encoding a two-component regulator (PnpRS) are located immediately upstream of the pst1 operon. Both the pst1 and pst2 operons encode putative PhoU-family regulators (PhoU1 and PhoU2) at their ends. This study addresses why S. pneumoniae contains dual Pi uptake systems and the regulation and contribution of the Pst1 and Pst2 systems in conditions of high (mM) Pi amount and low (μM) Pi amount. We show that in unencapsulated mutants, both pst1 and pst2 can be deleted, and Pi is taken up by a third Na+/Pi co-transporter, designated as NptA. In contrast, either pst1 or pst2 is unexpectedly required for the growth of capsule producing strains. We used a combination of mutational analysis, transcript level determinations by qRT-PCR and RNA-Seq, assays for cellular PnpR~P amounts by SDS-PAGE, and pulse-Pi uptake experiments to study the regulation of Pi uptake. In high Pi medium, PhoU2 serves as the master negative regulator of Pst2 transporter function and PnpR~P levels (post-transcriptionally). ΔphoU2 mutants have high PnpR~P levels and induction of the pst1 operon, poor growth, and sensitivity to antibiotics, possibly due to high Pi accumulation. In low Pi medium, Pst2 is still active, but PnpR~P amount and pst1 operon levels increase. Together, these results support a model in which pneumococcus maintains high Pi transport in high and low Pi conditions that is required for optimal capsule biosynthesis.
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Affiliation(s)
- Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Dhriti Sinha
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Kyle J Wayne
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington Bloomington, IN, USA
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26
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Bajaj R, Bruce KE, Davidson AL, Rued BE, Stauffacher CV, Winkler ME. Biochemical characterization of essential cell division proteins FtsX and FtsE that mediate peptidoglycan hydrolysis by PcsB in Streptococcus pneumoniae. Microbiologyopen 2016; 5:738-752. [PMID: 27167971 PMCID: PMC5061712 DOI: 10.1002/mbo3.366] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/14/2016] [Accepted: 03/23/2016] [Indexed: 01/02/2023] Open
Abstract
The FtsEX:PcsB complex forms a molecular machine that carries out peptidoglycan (PG) hydrolysis during normal cell division of the major respiratory pathogenic bacterium, Streptococcus pneumoniae (pneumococcus). FtsX is an integral membrane protein and FtsE is a cytoplasmic ATPase that together structurally resemble ABC transporters. Instead of transport, FtsEX transduces signals from the cell division apparatus to stimulate PG hydrolysis by PcsB, which interacts with extracellular domains of FtsX. Structural studies of PcsB and one extracellular domain of FtsX have recently appeared, but little is known about the biochemical properties of the FtsE ATPase or the intact FtsX transducer protein. We report here purifications and characterizations of tagged FtsX and FtsE proteins. Pneumococcal FtsX‐GFP‐His and FtsX‐His could be overexpressed in Escherichia coli without toxicity, and FtsE‐His remained soluble during purification. FtsX‐His dimerizes in detergent micelles and when reconstituted in phospholipid nanodiscs. FtsE‐His binds an ATP analog with an affinity comparable to that of ATPase subunits of ABC transporters, and FtsE‐His preparations have a low, detectable ATPase activity. However, attempts to detect complexes of purified FtsX‐His, FtsE‐His, and PcsB‐His or coexpressed tagged FtsX and FtsE were not successful with the constructs and conditions tested so far. In working with nanodiscs, we found that PcsB‐His has an affinity for charged phospholipids, mediated partly by interactions with its coiled‐coil domain. Together, these findings represent first steps toward reconstituting the FtsEX:PcsB complex biochemically and provide information that may be relevant to the assembly of the complex on the surface of pneumococcal cells.
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Affiliation(s)
- Ruchika Bajaj
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Kevin E Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405
| | - Amy L Davidson
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Britta E Rued
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405
| | - Cynthia V Stauffacher
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, 47405.
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27
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Tsui HCT, Zheng JJ, Magallon AN, Ryan JD, Yunck R, Rued BE, Bernhardt TG, Winkler ME. Suppression of a deletion mutation in the gene encoding essential PBP2b reveals a new lytic transglycosylase involved in peripheral peptidoglycan synthesis in Streptococcus pneumoniae D39. Mol Microbiol 2016; 100:1039-65. [PMID: 26933838 DOI: 10.1111/mmi.13366] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In ellipsoid-shaped ovococcus bacteria, such as the pathogen Streptococcus pneumoniae (pneumococcus), side-wall (peripheral) peptidoglycan (PG) synthesis emanates from midcells and is catalyzed by the essential class B penicillin-binding protein PBP2b transpeptidase (TP). We report that mutations that inactivate the pneumococcal YceG-domain protein, Spd_1346 (renamed MltG), remove the requirement for PBP2b. ΔmltG mutants in unencapsulated strains accumulate inactivation mutations of class A PBP1a, which possesses TP and transglycosylase (TG) activities. The 'synthetic viable' genetic relationship between Δpbp1a and ΔmltG mutations extends to essential ΔmreCD and ΔrodZ mutations that misregulate peripheral PG synthesis. Remarkably, the single MltG(Y488D) change suppresses the requirement for PBP2b, MreCD, RodZ and RodA. Structural modeling and comparisons, catalytic-site changes and an interspecies chimera indicate that pneumococcal MltG is the functional homologue of the recently reported MltG endo-lytic transglycosylase of Escherichia coli. Depletion of pneumococcal MltG or mltG(Y488D) increases sphericity of cells, and MltG localizes with peripheral PG synthesis proteins during division. Finally, growth of Δpbp1a ΔmltG or mltG(Y488D) mutants depends on induction of expression of the WalRK TCS regulon of PG hydrolases. These results fit a model in which MltG releases anchored PG glycan strands synthesized by PBP1a for crosslinking by a PBP2b:RodA complex in peripheral PG synthesis.
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Affiliation(s)
| | - Jiaqi J Zheng
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Ariel N Magallon
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - John D Ryan
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Rachel Yunck
- Department of Microbiology and Immunology, Harvard Medical School, Boston, MA, 02115, USA
| | - Britta E Rued
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
| | - Thomas G Bernhardt
- Department of Microbiology and Immunology, Harvard Medical School, Boston, MA, 02115, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
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28
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Fu Y, Bruce KE, Rued B, Winkler ME, Giedroc DP. 1H, 13C, 15N resonance assignments of the extracellular loop 1 domain (ECL1) of Streptococcus pneumoniae D39 FtsX, an essential cell division protein. Biomol NMR Assign 2016; 10:89-92. [PMID: 26370567 PMCID: PMC4789122 DOI: 10.1007/s12104-015-9644-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/09/2015] [Indexed: 06/05/2023]
Abstract
FtsX is an integral membrane protein from Streptococcus pneumoniae (pneumococcus) that harbors an extracellular loop 1 domain (FtsX(Spn)ECL1) that interacts with PcsB, an peptidoglycan hydrolase that is essential for cell growth and division. Here, we report nearly complete backbone and side chain resonance assignments and a secondary structural analysis of FtsX(Spn)ECL1 (residues 47-168 of FtsX) as first steps toward structure determination of FtsX(Spn)ECL1.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, Indiana University, 212 S. Hawthorne Drive, Bloomington, IN, 47405-7102, USA
| | - Kevin E Bruce
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Britta Rued
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, 212 S. Hawthorne Drive, Bloomington, IN, 47405-7102, USA.
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29
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Hoover SE, Perez AJ, Tsui HCT, Sinha D, Smiley DL, DiMarchi RD, Winkler ME, Lazazzera BA. A new quorum-sensing system (TprA/PhrA) for Streptococcus pneumoniae D39 that regulates a lantibiotic biosynthesis gene cluster. Mol Microbiol 2015; 97:229-43. [PMID: 25869931 DOI: 10.1111/mmi.13029] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2015] [Indexed: 12/20/2022]
Abstract
The Phr peptides of the Bacillus species mediate quorum sensing, but their identification and function in other species of bacteria have not been determined. We have identified a Phr peptide quorum-sensing system (TprA/PhrA) that controls the expression of a lantibiotic gene cluster in the Gram-positive human pathogen, Streptococcus pneumoniae. Lantibiotics are highly modified peptides that are part of the bacteriocin family of antimicrobial peptides. We have characterized the basic mechanism for a Phr-peptide signaling system in S. pneumoniae and found that it induces the expression of the lantibiotic genes when pneumococcal cells are at high density in the presence of galactose, a main sugar of the human nasopharynx, a highly competitive microbial environment. Activity of the Phr peptide system is not seen when pneumococcal cells are grown with glucose, the preferred carbon source and the most prevalent sugar encountered by S. pneumoniae during invasive disease. Thus, the lantibiotic genes are expressed under the control of both cell density signals via the Phr peptide system and nutritional signals from the carbon source present, suggesting that quorum sensing and the lantibiotic machinery may help pneumococcal cells compete for space and resources during colonization of the nasopharynx.
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Affiliation(s)
- Sharon E Hoover
- Department of Microbiology, Immunology and Molecular Genetics, University of California, 609 Charles E. Young Dr. East, 1602 Molecular Science Building, Los Angeles, California, 90095, USA
| | - Amilcar J Perez
- Department of Microbiology, Immunology and Molecular Genetics, University of California, 609 Charles E. Young Dr. East, 1602 Molecular Science Building, Los Angeles, California, 90095, USA
| | - Ho-Ching T Tsui
- Department of Biology, Indiana University Bloomington, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
| | - Dhriti Sinha
- Department of Biology, Indiana University Bloomington, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
| | - David L Smiley
- Department of Chemistry, Indiana University Bloomington, 800 E. Kirkwood Avenue, Bloomington, Indiana, 47405, USA
| | - Richard D DiMarchi
- Department of Chemistry, Indiana University Bloomington, 800 E. Kirkwood Avenue, Bloomington, Indiana, 47405, USA
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
| | - Beth A Lazazzera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, 609 Charles E. Young Dr. East, 1602 Molecular Science Building, Los Angeles, California, 90095, USA
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30
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Tsui HCT, Boersma MJ, Vella SA, Kocaoglu O, Kuru E, Peceny JK, Carlson EE, VanNieuwenhze MS, Brun YV, Shaw SL, Winkler ME. Pbp2x localizes separately from Pbp2b and other peptidoglycan synthesis proteins during later stages of cell division of Streptococcus pneumoniae D39. Mol Microbiol 2014; 94:21-40. [PMID: 25099088 DOI: 10.1111/mmi.12745] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2014] [Indexed: 11/27/2022]
Abstract
The relative localization patterns of class B penicillin-binding proteins Pbp2x and Pbp2b were used as positional indicators of septal and peripheral (side-wall-like) peptidoglycan (PG) synthesis, respectively, in the mid-cell regions of Streptococcus pneumoniae cells at different stages of division. We confirm that Pbp2x and Pbp2b are essential in the strain D39 genetic background, which differs from that of laboratory strains. We show that Pbp2b, like Pbp2x and class A Pbp1a, follows a different localization pattern than FtsZ and remains at division septa after FtsZ reappears at the equators of daughter cells. Pulse-experiments with fluorescent D-amino acids (FDAAs) were performed in wild-type cells and in cells in which Pbp2x activity was preferentially inhibited by methicillin or Pbp2x amount was depleted. These experiments show that Pbp2x activity separates from that of other PBPs to the centres of constricting septa in mid-to-late divisional cells resolved by high-resolution 3D-SIM microscopy. Dual-protein and protein-fluorescent vancomycin 2D and 3D-SIM immunofluorescence microscopy (IFM) of cells at different division stages corroborate that Pbp2x separates to the centres of septa surrounded by an adjacent constricting ring containing Pbp2b, Pbp1a and regulators, StkP and MreC. The separate localization of Pbp2x suggests distinctive roles in completing septal PG synthesis and remodelling.
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Affiliation(s)
- Ho-Ching T Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Michael J Boersma
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Stephen A Vella
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Ozden Kocaoglu
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Erkin Kuru
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Julia K Peceny
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Erin E Carlson
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405.,Department of Chemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Michael S VanNieuwenhze
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405.,Department of Chemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Yves V Brun
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405.,Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Sidney L Shaw
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Malcolm E Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405.,Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
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31
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Land AD, Tsui HCT, Kocaoglu O, Vella SA, Shaw SL, Keen SK, Sham LT, Carlson EE, Winkler ME. Requirement of essential Pbp2x and GpsB for septal ring closure in Streptococcus pneumoniae D39. Mol Microbiol 2013; 90:939-55. [PMID: 24118410 DOI: 10.1111/mmi.12408] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2013] [Indexed: 11/29/2022]
Abstract
Bacterial cell shapes are manifestations of programs carried out by multi-protein machines that synthesize and remodel the resilient peptidoglycan (PG) mesh and other polymers surrounding cells. GpsB protein is conserved in low-GC Gram-positive bacteria and is not essential in rod-shaped Bacillus subtilis, where it plays a role in shuttling penicillin-binding proteins (PBPs) between septal and side-wall sites of PG synthesis. In contrast, we report here that GpsB is essential in ellipsoid-shaped, ovococcal Streptococcus pneumoniae (pneumococcus), and depletion of GpsB leads to formation of elongated, enlarged cells containing unsegregated nucleoids and multiple, unconstricted rings of fluorescent-vancomycin staining, and eventual lysis. These phenotypes are similar to those caused by selective inhibition of Pbp2x by methicillin that prevents septal PG synthesis. Dual-protein 2D and 3D-SIM (structured illumination) immunofluorescence microscopy (IFM) showed that GpsB and FtsZ have overlapping, but not identical, patterns of localization during cell division and that multiple, unconstricted rings of division proteins FtsZ, Pbp2x, Pbp1a and MreC are in elongated cells depleted of GpsB. These patterns suggest that GpsB, like Pbp2x, mediates septal ring closure. This first dual-protein 3D-SIM IFM analysis also revealed separate positioning of Pbp2x and Pbp1a in constricting septa, consistent with two separable PG synthesis machines.
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Affiliation(s)
- Adrian D Land
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405, USA
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32
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Kocaoglu O, Calvo RA, Sham LT, Cozy LM, Lanning BR, Francis S, Winkler ME, Kearns DB, Carlson EE. Selective penicillin-binding protein imaging probes reveal substructure in bacterial cell division. ACS Chem Biol 2012; 7:1746-53. [PMID: 22909777 DOI: 10.1021/cb300329r] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The peptidoglycan cell wall is a common target for antibiotic therapy, but its structure and assembly are only partially understood. Peptidoglycan synthesis requires a suite of penicillin-binding proteins (PBPs), the individual roles of which are difficult to determine because each enzyme is often dispensable for growth perhaps due to functional redundancy. To address this challenge, we sought to generate tools that would enable selective examination of a subset of PBPs. We designed and synthesized fluorescent and biotin derivatives of the β-lactam-containing antibiotic cephalosporin C. These probes facilitated specific in vivo labeling of active PBPs in both Bacillus subtilis PY79 and an unencapsulated derivative of D39 Streptococcus pneumoniae. Microscopy and gel-based analysis indicated that the cephalosporin C-based probes are more selective than BOCILLIN-FL, a commercially available penicillin V analogue, which labels all PBPs. Dual labeling of live cells performed by saturation of cephalosporin C-susceptible PBPs followed by tagging of the remaining PBP population with BOCILLIN-FL demonstrated that the two sets of PBPs are not co-localized. This suggests that even PBPs that are located at a particular site (e.g., septum) are not all intermixed, but rather that PBP subpopulations are discretely localized. Accordingly, the Ceph C probes represent new tools to explore a subset of PBPs and have the potential to facilitate a deeper understand of the roles of this critical class of proteins.
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Affiliation(s)
- Ozden Kocaoglu
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Rebecca A. Calvo
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Lok-To Sham
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Loralyn M. Cozy
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Bryan R. Lanning
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Samson Francis
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Malcolm E. Winkler
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Daniel B. Kearns
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
| | - Erin E. Carlson
- Departments of †Chemistry, ‡Molecular and Cellular Biochemistry, and §Biology, Indiana University, Bloomington, Indiana
47405, United
States
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33
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Wayne KJ, Li S, Kazmierczak KM, Tsui HCT, Winkler ME. Involvement of WalK (VicK) phosphatase activity in setting WalR (VicR) response regulator phosphorylation level and limiting cross-talk in Streptococcus pneumoniae D39 cells. Mol Microbiol 2012; 86:645-60. [PMID: 23013245 DOI: 10.1111/mmi.12006] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2012] [Indexed: 11/30/2022]
Abstract
WalRK (YycFG) two-component systems (TCSs) of low-GC Gram-positive bacteria play critical roles in regulating peptidogylcan hydrolase genes involved in cell division and wall stress responses. The WalRK (VicRK) TCSs of Streptococcus pneumoniae (pneumococcus) and other Streptococcus species show numerous differences with those of other low-GC species. Notably, the pneumococcal WalK sensor kinase is not essential for normal growth in culture, unlike its homologues in Bacillus and Staphylococcus species. The WalK sensor kinase possesses histidine autokinase activity and mediates dephosphorylation of phosphorylated WalR∼P response regulator. To understand the contributions of these two WalK activities to pneumococcal growth, we constructed and characterized a set of walK kinase and phosphatase mutants in biochemical reactions and in cells. We identified an amino acid substitution in WalK that significantly reduces phosphatase activity, but not other activities. Comparisons were made between WalRK regulon expression levels and WalR∼P amounts in cells determined by Phos-tag SDS-PAGE. Reduction of WalK phosphatase activity resulted in nearly 90% phosphorylation to WalR∼P, consistent with the conclusion that WalK phosphatase is strongly active in exponentially growing cells. WalK phosphatase activity was also shown to depend on the WalK PAS domain and to limit cross-talk and the recovery of WalR∼P from walK(+) cells.
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Affiliation(s)
- Kyle J Wayne
- Department of Biology, Indiana University Bloomington, 1001 East Third Street, Bloomington, IN, 47405, USA
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Sham LT, Tsui HCT, Land AD, Barendt SM, Winkler ME. Recent advances in pneumococcal peptidoglycan biosynthesis suggest new vaccine and antimicrobial targets. Curr Opin Microbiol 2012; 15:194-203. [PMID: 22280885 DOI: 10.1016/j.mib.2011.12.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 01/09/2023]
Abstract
Streptococcus pneumoniae is a serious human respiratory pathogen that has the capacity to evade capsule-based vaccines and to develop multidrug antibiotic resistance. This review summarizes recent advances in understanding the mechanisms and regulation of peptidoglycan (PG) biosynthesis that result in ellipsoid-shaped, ovococcus Streptococcus cells. New results support a two-state model for septal and peripheral PG synthesis at mid-cell, involvement of essential cell division proteins in PG remodeling, and mid-cell localization of proteins that organize PG biosynthesis and that form the protein translocation apparatus. PG biosynthesis proteins have already turned up as promising vaccine candidates and targets of antibiotics. Properties of several recently characterized proteins that mediate or regulate PG biosynthesis suggest a source of additional targets for therapies against pneumococcus.
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Affiliation(s)
- Lok-To Sham
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405, United States
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Hsueh YH, Cozy LM, Sham LT, Calvo RA, Gutu AD, Winkler ME, Kearns DB. DegU-phosphate activates expression of the anti-sigma factor FlgM in Bacillus subtilis. Mol Microbiol 2011; 81:1092-108. [PMID: 21736639 DOI: 10.1111/j.1365-2958.2011.07755.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bacterial flagellum is a complex molecular machine that is assembled by more than 30 proteins and is rotated to propel cells either through liquids or over solid surfaces. Flagellar gene expression is extensively regulated to co-ordinate flagellar assembly in both space and time. In Bacillus subtilis, the proteins of unknown function, SwrA and SwrB, and the alternative sigma factor σ(D) are required to activate expression of the flagellar filament protein, flagellin. Here we determine that in the absence of SwrA and SwrB, the phosphorylated form of the response regulator DegU inhibits σ(D) -dependent gene expression indirectly by binding to the P(flgM) promoter region and activating expression of the anti-sigma factor FlgM. We further demonstrate that DegU-P-dependent activation of FlgM is essential to inhibit flagellin expression when flagellar basal body assembly is disrupted. Regulation of FlgM is poorly understood outside of Salmonella, and differential control of FlgM expression may be a common means of coupling flagellin expression to flagellar assembly.
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Affiliation(s)
- Yi-Huang Hsueh
- Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN 47405, USA
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Jacobsen FE, Kazmierczak KM, Lisher JP, Winkler ME, Giedroc DP. Interplay between manganese and zinc homeostasis in the human pathogen Streptococcus pneumoniae. Metallomics 2011; 3:38-41. [PMID: 21275153 DOI: 10.1039/c0mt00050g] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ICP-MS analysis of Streptococcus pneumoniae reveals a high cell-associated Mn(II) concentration that is comparable to that of Zn(II). Stressing these cells with 100–200 μM Zn(II) leads to a slow-growth phenotype and a total Mn(II) concentration that is reduced, with no decrease of other metal ions. Supplementation of the growth media with as little as 10 μM Mn(II) fully restores the growth defect and cell-associated Mn(II) to normal levels. DNA microarray analysis reveals that zinc stress induces the expected upregulation of czcD (encoding a zinc effluxer), but also a pleiotropic transcriptional response suggestive of mild cell wall stress. Genes encoding a nitric oxide (NO) detoxification system (nmlR) and the Mn(II) uptake system (psaBCA) are also induced. We conclude that Zn(II) toxicity results in a cytoplasmic Mn(II) deficiency, possibly caused by competition at the Mn(II) uptake transporter protein PsaA.
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Affiliation(s)
- Faith E Jacobsen
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
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Nichols RJ, Sen S, Choo YJ, Beltrao P, Zietek M, Chaba R, Lee S, Kazmierczak KM, Lee KJ, Wong A, Shales M, Lovett S, Winkler ME, Krogan NJ, Typas A, Gross CA. Phenotypic landscape of a bacterial cell. Cell 2010; 144:143-56. [PMID: 21185072 DOI: 10.1016/j.cell.2010.11.052] [Citation(s) in RCA: 498] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 11/07/2010] [Accepted: 11/24/2010] [Indexed: 01/09/2023]
Abstract
The explosion of sequence information in bacteria makes developing high-throughput, cost-effective approaches to matching genes with phenotypes imperative. Using E. coli as proof of principle, we show that combining large-scale chemical genomics with quantitative fitness measurements provides a high-quality data set rich in discovery. Probing growth profiles of a mutant library in hundreds of conditions in parallel yielded > 10,000 phenotypes that allowed us to study gene essentiality, discover leads for gene function and drug action, and understand higher-order organization of the bacterial chromosome. We highlight new information derived from the study, including insights into a gene involved in multiple antibiotic resistance and the synergy between a broadly used combinatory antibiotic therapy, trimethoprim and sulfonamides. This data set, publicly available at http://ecoliwiki.net/tools/chemgen/, is a valuable resource for both the microbiological and bioinformatic communities, as it provides high-confidence associations between hundreds of annotated and uncharacterized genes as well as inferences about the mode of action of several poorly understood drugs.
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Reyes-Caballero H, Guerra AJ, Jacobsen FE, Kazmierczak KM, Cowart D, Koppolu UMK, Scott RA, Winkler ME, Giedroc DP. The metalloregulatory zinc site in Streptococcus pneumoniae AdcR, a zinc-activated MarR family repressor. J Mol Biol 2010; 403:197-216. [PMID: 20804771 DOI: 10.1016/j.jmb.2010.08.030] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/14/2010] [Accepted: 08/16/2010] [Indexed: 12/11/2022]
Abstract
Streptococcus pneumoniae D39 AdcR (adhesin competence repressor) is the first metal-sensing member of the MarR (multiple antibiotic resistance repressor) family to be characterized. Expression profiling with a ΔadcR strain grown in liquid culture (brain-heart infusion) under microaerobic conditions revealed upregulation of 13 genes, including adcR and adcCBA, encoding a high-affinity ABC uptake system for zinc, and genes encoding cell-surface zinc-binding pneumococcal histidine triad (Pht) proteins and AdcAII (Lmb, laminin binding). The ΔadcR, H108Q and H112Q adcR mutant allelic strains grown in 0.2 mM Zn(II) exhibit a slow-growth phenotype and an approximately twofold increase in cell-associated Zn(II). Apo- and Zn(II)-bound AdcR are homodimers in solution and binding to a 28-mer DNA containing an adc operator is strongly stimulated by Zn(II) with K(DNA-Zn)=2.4 × 10(8) M(-1) (pH 6.0, 0.2 M NaCl, 25 °C). AdcR binds two Zn(II) per dimer, with stepwise Zn(II) affinities K(Zn1) and K(Zn2) of ≥10(9) M(-1) at pH 6.0 and ≥10(12) M(-1) at pH 8.0, and one to three lower affinity Zn(II) depending on the pH. X-ray absorption spectroscopy of the high-affinity site reveals a pentacoordinate N/O complex and no cysteine coordination, the latter finding corroborated by wild type-like functional properties of C30A AdcR. Alanine substitution of conserved residues His42 in the DNA-binding domain, and His108 and His112 in the C-terminal regulatory domain, abolish high-affinity Zn(II) binding and greatly reduce Zn(II)-activated binding to DNA. NMR studies reveal that these mutants adopt the same folded conformation as dimeric wild type apo-AdcR, but fail to conformationally switch upon Zn(II) binding. These studies implicate His42, His108 and H112 as metalloregulatory zinc ligands in S. pneumoniae AdcR.
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Guerra AJ, Reyes-Caballero H, Jacobsen FE, Koppolu UK, Scott RA, Kazmierczak K, Winkler ME, Giedroc DP. On the Structure, Function and Metalloregulatory Properties of the Zinc-Activated Repressor Streptococcus Pneumoniae AdcR. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Tsui HCT, Mukherjee D, Ray VA, Sham LT, Feig AL, Winkler ME. Identification and characterization of noncoding small RNAs in Streptococcus pneumoniae serotype 2 strain D39. J Bacteriol 2010; 192:264-79. [PMID: 19854910 PMCID: PMC2798261 DOI: 10.1128/jb.01204-09] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 10/12/2009] [Indexed: 11/20/2022] Open
Abstract
We report a search for small RNAs (sRNAs) in the low-GC, gram-positive human pathogen Streptococcus pneumoniae. Based on bioinformatic analyses by Livny et al. (J. Livny, A. Brencic, S. Lory, and M. K. Waldor, Nucleic Acids Res. 34:3484-3493, 2006), we tested 40 candidates by Northern blotting and confirmed the expression of nine new and one previously reported (CcnA) sRNAs in strain D39. CcnA is one of five redundant sRNAs reported by Halfmann et al. (A. Halfmann, M. Kovacs, R. Hakenbeck, and R. Bruckner, Mol. Microbiol. 66:110-126, 2007) that are positively controlled by the CiaR response regulator. We characterized 3 of these 14 sRNAs: Spd-sr17 (144 nucleotides [nt]; decreased in stationary phase), Spd-sr37 (80 nt; strongly expressed in all growth phases), and CcnA (93 nt; induced by competence stimulatory peptide). Spd-sr17 and CcnA likely fold into structures containing single-stranded regions between hairpin structures, whereas Spd-sr37 forms a base-paired structure. Primer extension mapping and ectopic expression in deletion/insertion mutants confirmed the independent expression of the three sRNAs. Microarray analyses indicated that insertion/deletion mutants in spd-sr37 and ccnA exerted strong cis-acting effects on the transcription of adjacent genes, indicating that these sRNA regions are also cotranscribed in operons. Deletion or overexpression of the three sRNAs did not cause changes in growth, certain stress responses, global transcription, or virulence. Constitutive ectopic expression of CcnA reversed some phenotypes of D39 Delta ciaR mutants, but attempts to link CcnA to -E to comC as a target were inconclusive in ciaR(+) strains. These results show that S. pneumoniae, which lacks known RNA chaperones, expresses numerous sRNAs, but three of these sRNAs do not strongly affect common phenotypes or transcription patterns.
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Affiliation(s)
- Ho-Ching Tiffany Tsui
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
| | - Dhriti Mukherjee
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
| | - Valerie A. Ray
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
| | - Lok-To Sham
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
| | - Andrew L. Feig
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
| | - Malcolm E. Winkler
- Department of Biology, Indiana University—Bloomington, Bloomington, Indiana 47405, Department of Chemistry, Wayne State University, 5101 Cass Ave., Detroit, Michigan 48202
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Kazmierczak KM, Wayne KJ, Rechtsteiner A, Winkler ME. Roles of rel(Spn) in stringent response, global regulation and virulence of serotype 2 Streptococcus pneumoniae D39. Mol Microbiol 2009; 72:590-611. [PMID: 19426208 PMCID: PMC2739083 DOI: 10.1111/j.1365-2958.2009.06669.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
RelA/SpoT homologue (RSH) proteins have (p)ppGpp synthetase and hydrolase activities that mediate major global responses to nutrient limitation and other stresses. RSH proteins are conserved in most bacteria and play diverse roles in bacterial pathogenesis. We report here that the RSH protein of Streptococcus pneumoniae, Rel(Spn), can be deleted and is the primary source of (p)ppGpp synthesis in virulent strain D39 under some conditions. A D39 Deltarel(Spn) mutant grew well in complex medium, but did not grow in chemically defined medium unless supplemented with the metals copper and manganese. Transcriptome analysis of D39 rel(+)(Spn) and Deltarel(Spn) strains treated with mupirocin revealed rel(Spn)-independent (translation stress), rel(Spn)-dependent (stringent response) and Deltarel(Spn)-dependent changes, suggesting that rel(Spn) and (p)ppGpp amount play wide-ranging homeostatic roles in pneumococcal physiology, besides adjusting macromolecular synthesis and transport in response to nutrient availability. Notably, the rel(Spn)-dependent response included significant upregulation of the ply operon encoding pneumolysin toxin, whereas the Deltarel(Spn)-dependent response affected expression linked to the VicRK and CiaRH two-component systems. Finally, a D39 Deltarel(Spn) mutant was severely attenuated and displayed a significantly altered course of disease progression in a mouse model of infection, which was restored to normal by an ectopic copy of rel(+)(Spn).
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Affiliation(s)
| | - Kyle J. Wayne
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405 U.S.A
| | - Andreas Rechtsteiner
- Center for Genomics and Bioinformatics, Indiana University Bloomington, Bloomington, Indiana 47405 U.S.A
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana 47405 U.S.A
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42
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Ramos-Montañez S, Tsui HCT, Wayne KJ, Morris JL, Peters LE, Zhang F, Kazmierczak KM, Sham LT, Winkler ME. Polymorphism and regulation of the spxB (pyruvate oxidase) virulence factor gene by a CBS-HotDog domain protein (SpxR) in serotype 2 Streptococcus pneumoniae. Mol Microbiol 2007; 67:729-46. [PMID: 18179423 DOI: 10.1111/j.1365-2958.2007.06082.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
spxB-encoded pyruvate oxidase is a major virulence factor of Streptococcus pneumoniae. During aerobic growth, SpxB synthesizes H2O2 and acetyl phosphate, which play roles in metabolism, signalling, and oxidative stress. We report here the first cis- and trans-acting regulatory elements for spxB transcription. These elements were identified in a genetic screen for spontaneous mutations that caused colonies of strain D39 to change from a semitransparent to an opaque appearance. Six of the seven opaque colonies recovered (frequency approximately 3 x 10(-5)) were impaired for SpxB function or expression. Two mutations changed amino acids in SpxB likely required for cofactor or subunit binding. One mutation defined a cis-acting adjacent direct repeat required for optimal spxB transcription. The other three spontaneous mutations created the same frameshift near the start of the trans-acting spxR regulatory gene. The SpxR protein contains helix-turn-helix, CBS and HotDog domains implicated in binding DNA, adenosyl compounds, and CoA-containing compounds respectively, and suggest that SpxR positively regulates spxB transcription in response to energy and metabolic state. Microarray analyses unexpectedly demonstrated that SpxR also positively regulates the strH exoglycosidase gene, which, like spxB, has been implicated in colonization. Finally, SpxR is required for full virulence in a murine model of infection.
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Lanie JA, Ng WL, Kazmierczak KM, Andrzejewski TM, Davidsen TM, Wayne KJ, Tettelin H, Glass JI, Winkler ME. Genome sequence of Avery's virulent serotype 2 strain D39 of Streptococcus pneumoniae and comparison with that of unencapsulated laboratory strain R6. J Bacteriol 2006; 189:38-51. [PMID: 17041037 PMCID: PMC1797212 DOI: 10.1128/jb.01148-06] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a leading human respiratory pathogen that causes a variety of serious mucosal and invasive diseases. D39 is an historically important serotype 2 strain that was used in experiments by Avery and coworkers to demonstrate that DNA is the genetic material. Although isolated nearly a century ago, D39 remains extremely virulent in murine infection models and is perhaps the strain used most frequently in current studies of pneumococcal pathogenesis. To date, the complete genome sequences have been reported for only two S. pneumoniae strains: TIGR4, a recent serotype 4 clinical isolate, and laboratory strain R6, an avirulent, unencapsulated derivative of strain D39. We report here the genome sequences and new annotation of two different isolates of strain D39 and the corrected sequence of strain R6. Comparisons of these three related sequences allowed deduction of the likely sequence of the D39 progenitor and mutations that arose in each isolate. Despite its numerous repeated sequences and IS elements, the serotype 2 genome has remained remarkably stable during cultivation, and one of the D39 isolates contains only five relatively minor mutations compared to the deduced D39 progenitor. In contrast, laboratory strain R6 contains 71 single-base-pair changes, six deletions, and four insertions and has lost the cryptic pDP1 plasmid compared to the D39 progenitor strain. Many of these mutations are in or affect the expression of genes that play important roles in regulation, metabolism, and virulence. The nature of the mutations that arose spontaneously in these three strains, the relative global transcription patterns determined by microarray analyses, and the implications of the D39 genome sequences to studies of pneumococcal physiology and pathogenesis are presented and discussed.
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Affiliation(s)
- Joel A Lanie
- Department of Biology, Indiana University Bloomington, Jordan Hall 142, Bloomington, IN 47405, USA
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Winkler ME, Kispert A, Wunderlich S, Schwanke K, Groos S, Schmiedl A, Menke S, Beier J, Gruh I, Haverich A, Martin U. Differentiation of embryonic stem cells into type-II pneumocytes. Pneumologie 2006. [DOI: 10.1055/s-2005-925492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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45
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Gilmour R, Foster JE, Sheng Q, McClain JR, Riley A, Sun PM, Ng WL, Yan D, Nicas TI, Henry K, Winkler ME. New class of competitive inhibitor of bacterial histidine kinases. J Bacteriol 2005; 187:8196-200. [PMID: 16291694 PMCID: PMC1291283 DOI: 10.1128/jb.187.23.8196-8200.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial histidine kinases have been proposed as targets for the discovery of new antibiotics, yet few specific inhibitors of bacterial histidine kinases have been reported. We report here a novel thienopyridine (TEP) compound that inhibits bacterial histidine kinases competitively with respect to ATP but does not comparably inhibit mammalian serine/threonine kinases. Although it partitions into membranes and does not inhibit the growth of bacterial or mammalian cells, TEP could serve as a starting compound for a new class of histidine kinase inhibitors with antibacterial activity.
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Ng WL, Tsui HCT, Winkler ME. Regulation of the pspA virulence factor and essential pcsB murein biosynthetic genes by the phosphorylated VicR (YycF) response regulator in Streptococcus pneumoniae. J Bacteriol 2005; 187:7444-59. [PMID: 16237028 PMCID: PMC1272996 DOI: 10.1128/jb.187.21.7444-7459.2005] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2005] [Accepted: 08/08/2005] [Indexed: 02/06/2023] Open
Abstract
The VicRK (YycFG) two-component regulatory system (TCS) is required for virulence of the human respiratory pathogen Streptococcus pneumoniae (pneumococcus). The VicR (YycF) response regulator (RR) is essential through its positive regulation of pcsB, which encodes an extracellular protein that mediates murein biosynthesis. To determine other genes that are regulated by VicR, we performed microarray analyses on a unique DeltavicR deletion mutant, which was constructed by uncoupling regulation of pcsB. Results from these microarray experiments support the idea that the VicR RR exerts strong positive regulation on the transcription of a set of genes encoding important surface proteins, including the PspA virulence factor, two proteins (Spr0096 and Spr1875) containing LysM peptidoglycan-binding domains, and a putative membrane protein (Spr0709) of unknown function. To demonstrate direct regulation, we performed band shift and footprinting experiments using purified unphosphorylated VicR and phosphorylated VicR-P, which was prepared by reaction with acetyl phosphate. VicR and VicR-P bound to regions upstream of pcsB, pspA, spr0096, spr1875, and spr0709. Phosphorylation of VicR to VicR-P increased the apparent strength and changed the nature of binding to these regions. DNase I footprinting of VicR and VicR-P bound to regions upstream of pcsB, pspA, spr0096, and spr1875 showed protection of extended regions containing a degenerate sequence related to a previously proposed consensus. These combined approaches did not support autoregulation of the vicRKX operon or substantive direct regulation of fatty acid biosynthesis by VicR or VicR-P. However, the DeltavicR mutant required fatty acids in some conditions, which supports the notion that the VicRK TCS may mediate membrane integrity as well as murein biosynthesis and virulence factor expression in S. pneumoniae.
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Affiliation(s)
- Wai-Leung Ng
- Department of Biology, Indiana University, Jordan Hall 142, Bloomington, IN 47405, USA
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47
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Gee JM, Valderas MW, Kovach ME, Grippe VK, Robertson GT, Ng WL, Richardson JM, Winkler ME, Roop RM. The Brucella abortus Cu,Zn superoxide dismutase is required for optimal resistance to oxidative killing by murine macrophages and wild-type virulence in experimentally infected mice. Infect Immun 2005; 73:2873-80. [PMID: 15845493 PMCID: PMC1087332 DOI: 10.1128/iai.73.5.2873-2880.2005] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two-dimensional gel electrophoretic analysis of cell lysates from Brucella abortus 2308 and the isogenic hfq mutant Hfq3 revealed that the RNA binding protein Hfq (also known as host factor I or HF-I) is required for the optimal stationary phase production of the periplasmic Cu,Zn superoxide dismutase SodC. An isogenic sodC mutant, designated MEK2, was constructed from B. abortus 2308 by gene replacement, and the sodC mutant exhibited much greater susceptibility to killing by O(2)(-) generated by pyrogallol and the xanthine oxidase reaction than the parental 2308 strain supporting a role for SodC in protecting this bacterium from O(2)(-) of exogenous origin. The B. abortus sodC mutant was also found to be much more sensitive to killing by cultured resident peritoneal macrophages from C57BL6J mice than 2308, and the attenuation displayed by MEK2 in cultured murine macrophages was enhanced when these phagocytes were treated with gamma interferon (IFN-gamma). The attenuation displayed by the B. abortus sodC mutant in both resting and IFN-gamma-activated macrophages was alleviated, however, when these host cells were treated with the NADPH oxidase inhibitor apocynin. Consistent with its increased susceptibility to killing by cultured murine macrophages, the B. abortus sodC mutant also displayed significant attenuation in experimentally infected C57BL6J mice compared to the parental strain. These experimental findings indicate that SodC protects B. abortus 2308 from the respiratory burst of host macrophages. They also suggest that reduced SodC levels may contribute to the attenuation displayed by the B. abortus hfq mutant Hfq3 in the mouse model.
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Affiliation(s)
- Jason M Gee
- Department of Microbiology and Immunology, East Carolina University School of Medicine, 600 Moye Boulevard, Greenville, NC 27834, USA.
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48
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Valderas MW, Alcantara RB, Baumgartner JE, Bellaire BH, Robertson GT, Ng WL, Richardson JM, Winkler ME, Roop RM. Role of HdeA in acid resistance and virulence in Brucella abortus 2308. Vet Microbiol 2005; 107:307-12. [PMID: 15863292 DOI: 10.1016/j.vetmic.2005.01.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Revised: 12/30/2004] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
Two-dimensional gel electrophoretic analysis of cell lysates suggests that stationary phase production of wild-type levels of an ortholog of the low pH dependent chaperone HdeA in Brucella abortus 2308 during growth in a minimal medium requires the presence of the RNA binding protein Hfq. Although mutational analysis demonstrated that HdeA contributes to acid resistance in this bacterium, this protein is not required for wild-type virulence in the BALB/c mouse model. These experimental findings indicate that the brucellae rely upon additional gene products to resist the acidic conditions they encounter in the phagosomal compartment of host macrophages.
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Affiliation(s)
- Michelle Wright Valderas
- Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, NC 27834, USA
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49
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Ng WL, Kazmierczak KM, Winkler ME. Defective cell wall synthesis in Streptococcus pneumoniae R6 depleted for the essential PcsB putative murein hydrolase or the VicR (YycF) response regulator. Mol Microbiol 2004; 53:1161-75. [PMID: 15306019 DOI: 10.1111/j.1365-2958.2004.04196.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PcsB is a protein of unknown function(s) that influences the cell morphology of several pathogenic species of streptococcus. PcsB contains a CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) domain found in bacterial murein hydrolases; however, direct links between steps in cell wall biosynthesis and PcsB function(s) have not been demonstrated. We show here that pcsB is essential in the human respiratory pathogen, Streptococcus pneumoniae, that depletion of PcsB is bacteriostatic and that alanine substitutions in the conserved cysteine and histidine residues of the CHAP domain appear to be lethal. We stained wild-type parent and mutant bacteria deficient in expression of PcsB with fluorescent vancomycin and DAPI to determine patterns of cell wall synthesis and nucleoid segregation respectively. The wild-type parent strain exhibited ordered, simultaneous septal and equatorial cell wall synthesis. In contrast, reduced expression of PcsB resulted in formation of long chains of cells in which peptidoglycan synthesis occurred at nearly every division septum and cell equator. Severe depletion of PcsB led to abnormal, uncontrolled cell wall synthesis at misplaced septa and around large cells. Together, these physiological properties are consistent with a role for PcsB as a murein hydrolase that balances the extent of cell wall synthesis in S. pneumoniae. Finally, we show that the defects in morphology and cell wall synthesis that result from depletion of PcsB strongly resemble those caused by depletion of the essential VicRK two component regulatory system (TCS). This result and the essentiality of pcsB support the hypothesis that the essentiality of the VicRK TCS results from its positive regulation of PcsB expression.
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Affiliation(s)
- Wai-Leung Ng
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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Ng WL, Winkler ME. Singular structures and operon organizations of essential two-component systems in species of Streptococcus. Microbiology (Reading) 2004; 150:3096-8. [PMID: 15470090 DOI: 10.1099/mic.0.27550-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Wai-Leung Ng
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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