1
|
Jiang W, Lin T, Pan J, Rivera CE, Tincher C, Wang Y, Zhang Y, Gao X, Wang Y, Tsui HCT, Winkler ME, Lynch M, Long H. Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:198-211. [PMID: 38827133 PMCID: PMC11136922 DOI: 10.1007/s42995-024-00220-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 03/04/2024] [Indexed: 06/04/2024]
Abstract
Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic stability. However, our study of the wild-type Streptococcus pneumoniae D39, a pathogen responsible for many common diseases, revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation (MA) lines. This rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T direction. The high mutation rate may have resulted from a reduction in the overall efficiency of selection, conferred by the tiny effective population size in nature. In line with this, S. pneumoniae D39 also exhibited the lowest DNA mismatch-repair (MMR) efficiency among bacteria. Treatment with the antibiotic penicillin did not elevate the mutation rate, as penicillin did not induce DNA damage and S. pneumoniae lacks a stress response pathway. Our findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-024-00220-6.
Collapse
Affiliation(s)
- Wanyue Jiang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
| | - Tongtong Lin
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Jiao Pan
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Caitlyn E. Rivera
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Clayton Tincher
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Yaohai Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Yu Zhang
- School of Mathematics Science, Ocean University of China, Qingdao, 266000 China
| | - Xiang Gao
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, School of Life Science, Shandong University, Qingdao, 266237 China
| | - Yan Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Ho-Ching T. Tsui
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | | | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281 USA
| | - Hongan Long
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
| |
Collapse
|
2
|
Pan H, Shim A, Lubin MB, Belin BJ. Hopanoid lipids promote soybean -Bradyrhizobium symbiosis. mBio 2024; 15:e0247823. [PMID: 38445860 PMCID: PMC11005386 DOI: 10.1128/mbio.02478-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/04/2024] [Indexed: 03/07/2024] Open
Abstract
The symbioses between leguminous plants and nitrogen-fixing bacteria known as rhizobia are well known for promoting plant growth and sustainably increasing soil nitrogen. Recent evidence indicates that hopanoids, a family of steroid-like lipids, promote Bradyrhizobium symbioses with tropical legumes. To characterize hopanoids in Bradyrhizobium symbiosis with soybean, we validated a recently published cumate-inducible hopanoid mutant of Bradyrhizobium diazoefficiens USDA110, Pcu-shc::∆shc. GC-MS analysis showed that this strain does not produce hopanoids without cumate induction, and under this condition, is impaired in growth in rich medium and under osmotic, temperature, and pH stress. In planta, Pcu-shc::∆shc is an inefficient soybean symbiont with significantly lower rates of nitrogen fixation and low survival within the host tissue. RNA-seq revealed that hopanoid loss reduces the expression of flagellar motility and chemotaxis-related genes, further confirmed by swim plate assays, and enhances the expression of genes related to nitrogen metabolism and protein secretion. These results suggest that hopanoids provide a significant fitness advantage to B. diazoefficiens in legume hosts and provide a foundation for future mechanistic studies of hopanoid function in protein secretion and motility. A major problem for global sustainability is feeding our exponentially growing human population while available arable land decreases. Harnessing the power of plant-beneficial microbes is a potential solution, including increasing our reliance on the symbioses of leguminous plants and nitrogen-fixing rhizobia. This study examines the role of hopanoid lipids in the symbiosis between Bradyrhizobium diazoefficiens USDA110, an important commercial inoculant strain, and its economically significant host soybean. Our research extends our knowledge of the functions of bacterial lipids in symbiosis to an agricultural context, which may one day help improve the practical applications of plant-beneficial microbes in agriculture.
Collapse
Affiliation(s)
- Huiqiao Pan
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
| | - Ashley Shim
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Matthew B. Lubin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Brittany J. Belin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, USA
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| |
Collapse
|
3
|
Luo H, Qu X, Deng X, He L, Wu Y, Liu Y, He D, Yin J, Wang B, Gan F, Tang B, Tang XF. HtrAs are essential for the survival of the haloarchaeon Natrinema gari J7-2 in response to heat, high salinity, and toxic substances. Appl Environ Microbiol 2024; 90:e0204823. [PMID: 38289131 PMCID: PMC10880668 DOI: 10.1128/aem.02048-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/24/2023] [Indexed: 02/22/2024] Open
Abstract
Bacterial and eukaryotic HtrAs can act as an extracytoplasmic protein quality control (PQC) system to help cells survive in stress conditions, but the functions of archaeal HtrAs remain unknown. Particularly, haloarchaea route most secretory proteins to the Tat pathway, enabling them to fold properly in well-controlled cytoplasm with cytosolic PQC systems before secretion. It is unclear whether HtrAs are required for haloarchaeal survival and stress response. The haloarchaeon Natrinema gari J7-2 encodes three Tat signal peptide-bearing HtrAs (NgHtrA, NgHtrB, and NgHtrC), and the signal peptides of NgHtrA and NgHtrC contain a lipobox. Here, the in vitro analysis reveals that the three HtrAs show different profiles of temperature-, salinity-, and metal ion-dependent proteolytic activities and could exhibit chaperone-like activities to prevent the aggregation of reduced lysozyme when their proteolytic activities are inhibited at low temperatures or the active site is disrupted. The gene deletion and complementation assays reveal that NgHtrA and NgHtrC are essential for the survival of strain J7-2 at elevated temperature and/or high salinity and contribute to the resistance of this haloarchaeon to zinc and inhibitory substances generated from tryptone. Mutational analysis shows that the lipobox mediates membrane anchoring of NgHtrA or NgHtrC, and both the membrane-anchored and free extracellular forms of the two enzymes are involved in the stress resistance of strain J7-2, depending on the stress conditions. Deletion of the gene encoding NgHtrB in strain J7-2 causes no obvious growth defect, but NgHtrB can functionally substitute for NgHtrA or NgHtrC under some conditions.IMPORTANCEHtrA-mediated protein quality control plays an important role in the removal of aberrant proteins in the extracytoplasmic space of living cells, and the action mechanisms of HtrAs have been extensively studied in bacteria and eukaryotes; however, information about the function of archaeal HtrAs is scarce. Our results demonstrate that three HtrAs of the haloarchaeon Natrinema gari J7-2 possess both proteolytic and chaperone-like activities, confirming that the bifunctional nature of HtrAs is conserved across all three domains of life. Moreover, we found that NgHtrA and NgHtrC are essential for the survival of strain J7-2 under stress conditions, while NgHtrB can serve as a substitute for the other two HtrAs under certain circumstances. This study provides the first biochemical and genetic evidence of the importance of HtrAs for the survival of haloarchaea in response to stresses.
Collapse
Affiliation(s)
- Hongyi Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoyi Qu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xi Deng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Liping He
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yi Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yang Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Dan He
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jing Yin
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Bingxue Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Fei Gan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
| | - Bing Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
| | - Xiao-Feng Tang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
| |
Collapse
|
4
|
Pan H, Shim A, Lubin MB, Belin BJ. Hopanoid lipids promote soybean- Bradyrhizobium symbiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.04.556284. [PMID: 37732186 PMCID: PMC10508751 DOI: 10.1101/2023.09.04.556284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The symbioses between leguminous plants and nitrogen-fixing bacteria known as rhizobia are well known for promoting plant growth and sustainably increasing soil nitrogen. Recent evidence indicates that hopanoids, a family of steroid-like lipids, promote Bradyrhizobium symbioses with tropical legumes. To characterize hopanoids in Bradyrhizobium symbiosis with soybean, the most economically significant Bradyrhizobium host, we validated a recently published cumate-inducible hopanoid mutant of Bradyrhizobium diazoefficiens USDA110, Pcu- shc ::Δ shc . GC-MS analysis showed that this strain does not produce hopanoids without cumate induction, and under this condition, is impaired in growth in rich medium and under osmotic, temperature, and pH stress. In planta , Pcu- shc ::Δ shc is an inefficient soybean symbiont with significantly lower rates of nitrogen fixation and low survival within host tissue. RNA-seq revealed that hopanoid loss reduces expression of flagellar motility and chemotaxis-related genes, further confirmed by swim plate assays, and enhances expression of genes related to nitrogen metabolism and protein secretion. These results suggest that hopanoids provide a significant fitness advantage to B. diazoefficiens in legume hosts and provide a foundation for future mechanistic studies of hopanoid function in protein secretion and motility. IMPORTANCE A major problem for global sustainability is feeding our exponentially growing human population while available arable land is decreasing, especially in areas with the greatest population growth. Harnessing the power of plant-beneficial microbes has gained attention as a potential solution, including the increasing our reliance on the symbioses of leguminous plants and nitrogen-fixing rhizobia. This study examines the role of hopanoid lipids in the symbiosis between Bradyrhizobium diazoefficiens USDA110, an important commercial inoculant strain, and its economically important host soybean. Our research extends our knowledge of the functions of bacterial lipids in symbiosis to an agricultural context, which may one day help improve the practical applications of plant-beneficial microbes in agriculture.
Collapse
|
5
|
Mitchison-Field LM, Belin BJ. Bacterial lipid biophysics and membrane organization. Curr Opin Microbiol 2023; 74:102315. [PMID: 37058914 PMCID: PMC10523990 DOI: 10.1016/j.mib.2023.102315] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 04/16/2023]
Abstract
The formation of lateral microdomains is emerging as a central organizing principle in bacterial membranes. These microdomains are targets of antibiotic development and have the potential to enhance natural product synthesis, but the rules governing their assembly are unclear. Previous studies have suggested that microdomain formation is promoted by lipid phase separation, particularly by cardiolipin (CL) and isoprenoid lipids, and there is strong evidence that CL biosynthesis is required for recruitment of membrane proteins to cell poles and division sites. New work demonstrates that additional bacterial lipids may mediate membrane protein localization and function, opening the field for mechanistic evaluation of lipid-driven membrane organization in vivo.
Collapse
Affiliation(s)
- Lorna My Mitchison-Field
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Brittany J Belin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA; Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
6
|
Pyrogallol downregulates the expression of virulence-associated proteins in Acinetobacter baumannii and showing anti-infection activity by improving non-specific immune response in zebrafish model. Int J Biol Macromol 2023; 226:853-869. [PMID: 36526063 DOI: 10.1016/j.ijbiomac.2022.12.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
Acinetobacter baumannii, a virulent uropathogen with widespread antibiotic resistance, has arisen as a critical scientific challenge, necessitating the development of innovative therapeutic agents. This is the first study reveal the proteomic changes in A. baumannii upon pyrogallol treatment for understanding the mechanisms using nano-LC-MS/MS-based quantitative proteomics and qPCR analysis. The obtained results found that pyrogallol treatment dramatically downregulated the expression level of several key proteins such as GroEL, DnaK, ClpB, SodB, KatE, Bap, CsuA/B, PgaA, PgaC, BfmR, OmpA, and SecA in A. baumannii, which are involved in chaperone-mediated oxidative stress responses, antioxidant defence system, biofilm formation, virulence enzyme production, bacterial adhesion, capsule formation, and antibiotic resistance. Accordingly, the pyrogallol dramatically enhanced the lifespan of A. baumannii-infected zebrafish by inhibiting bacterial colonization, demonstrating the anti-infective potential of pyrogallol against A. baumannii. Further, the histopathological results also demonstrated the disease protection efficacy of pyrogallol against the pathognomonic sign of A. baumannii infection. In addition, the pyrogallol treatment effectively improved the immune parameters such as serum myeloperoxidase activity, leukocyte respiratory burst activity, and serum lysozyme activity in zebrafish against A. baumannii infection. Based on the results, the present study strongly proposes pyrogallol as a promising therapeutic agent for treating A. baumannii infection.
Collapse
|
7
|
Dewachter L, Dénéréaz J, Liu X, de Bakker V, Costa C, Baldry M, Sirard JC, Veening JW. Amoxicillin-resistant Streptococcus pneumoniae can be resensitized by targeting the mevalonate pathway as indicated by sCRilecs-seq. eLife 2022; 11:75607. [PMID: 35748540 PMCID: PMC9363119 DOI: 10.7554/elife.75607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/23/2022] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance in the important opportunistic human pathogen Streptococcus pneumoniae is on the rise. This is particularly problematic in the case of the β-lactam antibiotic amoxicillin, which is the first-line therapy. It is therefore crucial to uncover targets that would kill or resensitize amoxicillin-resistant pneumococci. To do so, we developed a genome-wide, single-cell based, gene silencing screen using CRISPR interference called sCRilecs-seq (subsets of CRISPR interference libraries extracted by fluorescence activated cell sorting coupled to next generation sequencing). Since amoxicillin affects growth and division, sCRilecs-seq was used to identify targets that are responsible for maintaining proper cell size. Our screen revealed that downregulation of the mevalonate pathway leads to extensive cell elongation. Further investigation into this phenotype indicates that it is caused by a reduced availability of cell wall precursors at the site of cell wall synthesis due to a limitation in the production of undecaprenyl phosphate (Und-P), the lipid carrier that is responsible for transporting these precursors across the cell membrane. The data suggest that, whereas peptidoglycan synthesis continues even with reduced Und-P levels, cell constriction is specifically halted. We successfully exploited this knowledge to create a combination treatment strategy where the FDA-approved drug clomiphene, an inhibitor of Und-P synthesis, is paired up with amoxicillin. Our results show that clomiphene potentiates the antimicrobial activity of amoxicillin and that combination therapy resensitizes amoxicillin-resistant S. pneumoniae. These findings could provide a starting point to develop a solution for the increasing amount of hard-to-treat amoxicillin-resistant pneumococcal infections. Streptococcus pneumoniae is a bacterium that can cause pneumonia, meningitis and other life-threatening illnesses in humans. Currently, many S. pneumoniae infections are treated with the antibiotic amoxicillin, which kills the bacteria by weakening a structure known as the cell wall that surrounds each bacterium. However, more and more S. pneumoniae cells are becoming resistant to amoxicillin, making it harder to treat such infections. We need new ways to effectively treat S. pneumoniae infections in humans. One potential strategy would be to combine amoxicillin with another drug that boosts the activity of amoxicillin so that it is able to kill the resistant bacteria. Two drugs that both target the same process in cells are more likely to boost each other’s activity. Therefore, Dewachter et al. decided to search for another drug that also weakens the cell wall of S. pneumoniae. The team first developed a new screening approach called sCRilecs-seq to silence individual genes in single S. pneumoniae cells. By looking at many cells that each had a different gene that was no longer active, the team were able to identify several genes that when silenced resulted in the cells becoming longer than normal cells (a sign the bacteria may have weak cell walls). Further experiments revealed that the cell walls of these bacteria were weaker than normal cells due to a shortage in a cell wall building material known as undecaprenyl phosphate. Dewachter et al. then demonstrated that combining an existing drug known as clomiphene – which is known to inhibit undecaprenyl phosphate production and is currently used to treat infertility in humans – together with amoxicillin is able to effectively kill S. pneumoniae that are resistant to amoxicillin alone. Clomiphene also boosted the activity of amoxicillin against S. pneumoniae that remain sensitive to the antibiotic. Before this new drug combination may be used to help treat S. pneumoniae infections in human patients, further experiments will be needed to find out the optimum dose of clomiphene to use with amoxicillin. In the future, the new screening approach developed by Dewachter et al. may also prove useful to other researchers studying a wide range of biological questions.
Collapse
Affiliation(s)
- Liselot Dewachter
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Julien Dénéréaz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Xue Liu
- Department of Pharmacology, Shenzhen University Health Science Center, Shenzhen, China
| | - Vincent de Bakker
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | | | | | | | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
8
|
Ali MQ, Kohler TP, Schulig L, Burchhardt G, Hammerschmidt S. Pneumococcal Extracellular Serine Proteases: Molecular Analysis and Impact on Colonization and Disease. Front Cell Infect Microbiol 2021; 11:763152. [PMID: 34790590 PMCID: PMC8592123 DOI: 10.3389/fcimb.2021.763152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/08/2021] [Indexed: 11/24/2022] Open
Abstract
The pathobiont Streptococcus pneumoniae causes life-threatening diseases, including pneumonia, sepsis, meningitis, or non-invasive infections such as otitis media. Serine proteases are enzymes that have been emerged during evolution as one of the most abundant and functionally diverse group of proteins in eukaryotic and prokaryotic organisms. S. pneumoniae expresses up to four extracellular serine proteases belonging to the category of trypsin-like or subtilisin-like family proteins: HtrA, SFP, PrtA, and CbpG. These serine proteases have recently received increasing attention because of their immunogenicity and pivotal role in the interaction with host proteins. This review is summarizing and focusing on the molecular and functional analysis of pneumococcal serine proteases, thereby discussing their contribution to pathogenesis.
Collapse
Affiliation(s)
- Murtadha Q Ali
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Thomas P Kohler
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Lukas Schulig
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Gerhard Burchhardt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute of Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| |
Collapse
|
9
|
The cell envelope of Staphylococcus aureus selectively controls the sorting of virulence factors. Nat Commun 2021; 12:6193. [PMID: 34702812 PMCID: PMC8548510 DOI: 10.1038/s41467-021-26517-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.
Collapse
|
10
|
Bai Q, Ma J, Zhang Z, Zhong X, Pan Z, Zhu Y, Zhang Y, Wu Z, Liu G, Yao H. YSIRK-G/S-directed translocation is required for Streptococcus suis to deliver diverse cell wall anchoring effectors contributing to bacterial pathogenicity. Virulence 2021; 11:1539-1556. [PMID: 33138686 PMCID: PMC7644249 DOI: 10.1080/21505594.2020.1838740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Streptococcus suis serotype 2 (SS2) is a significant zoonotic pathogen that is responsible for various swine diseases, even causing cytokine storms of Streptococcal toxic shock-like syndromes amongst human. Cell wall anchoring proteins with a C-terminal LPxTG are considered to play vital roles during SS2 infection; however, their exporting mechanism across cytoplasmic membranes has remained vague. This study found that YSIRK-G/S was involved in the exportation of LPxTG-anchoring virulence factors MRP and SspA in virulent SS2 strain ZY05719. The whole-genome analysis indicated that diverse LPxTG proteins fused with an N-terminal YSIRK-G/S motif are encoded in strain ZY05719. Two novel LPxTG proteins SspB and YzpA were verified to be exported via a putative transport system that was dependent on the YSIRK-G/S directed translocation, and portrayed vital functions during the infection of SS2 strain ZY05719. Instead of exhibiting an inactivation of C5a peptidase in SspB, another LPxTG protein with an N-terminal YSIRK-G/S motif from Streptococcus agalactiae was depicted to cleave the C5a component of the host complement. The consequent domain-architecture retrieval determined more than 10,000 SspB/YzpA like proteins that are extensively distributed in the Gram-positive bacteria, and most of them harbor diverse glycosyl hydrolase or peptidase domains within their middle regions, thus presenting their capability to interact with host cells. The said findings provide compelling evidence that LPxTG proteins with an N-terminal YSIRK-G/S motif are polymorphic effectors secreted by Gram-positive bacteria, which can be further proposed to define as cell wall anchoring effectors in a new subset.
Collapse
Affiliation(s)
- Qiankun Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Ze Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Xiaojun Zhong
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zihao Pan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yinchu Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Yue Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Zongfu Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Guangjin Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing, China.,Department of pathogenic diagnosis, OIE Reference Lab for Swine Streptococcosis , Nanjing, China
| |
Collapse
|
11
|
Huang M, Liu M, Huang L, Wang M, Jia R, Zhu D, Chen S, Zhao X, Zhang S, Gao Q, Zhang L, Cheng A. The activation and limitation of the bacterial natural transformation system: The function in genome evolution and stability. Microbiol Res 2021; 252:126856. [PMID: 34454311 DOI: 10.1016/j.micres.2021.126856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 12/26/2022]
Abstract
Bacteria can take up exogenous naked DNA and integrate it into their genomes, which has been regarded as a main contributor to bacterial evolution. The competent status of bacteria is influenced by environmental cues and by the immune systems of bacteria. Here, we review recent advances in understanding the working mechanisms underlying activation of the natural transformation system and limitations thereof. Environmental stresses including the presence of antimicrobials can activate the natural transformation system. However, bacterial enzymes (nucleases), non-coding RNAs, specific DNA sequences, the restriction-modification (R-M) systems, CRISPR-Cas systems and prokaryotic Argonaute proteins (Agos) are have been found to be involved in the limitation of the natural transformation system. Together, this review represents an opportunity to gain insight into bacterial genome stability and evolution.
Collapse
Affiliation(s)
- Mi Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Li Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China.
| |
Collapse
|
12
|
Peters K, Schweizer I, Hakenbeck R, Denapaite D. New Insights into Beta-Lactam Resistance of Streptococcus pneumoniae: Serine Protease HtrA Degrades Altered Penicillin-Binding Protein 2x. Microorganisms 2021; 9:microorganisms9081685. [PMID: 34442764 PMCID: PMC8400419 DOI: 10.3390/microorganisms9081685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 11/18/2022] Open
Abstract
Reduced amounts of the essential penicillin-binding protein 2x (PBP2x) were detected in two cefotaxime-resistant Streptococcus pneumoniae laboratory mutants C405 and C606. These mutants contain two or four mutations in the penicillin-binding domain of PBP2x, respectively. The transcription of the pbp2x gene was not affected in both mutants; thus, the reduced PBP2x amounts were likely due to post-transcriptional regulation. The mutants carry a mutation in the histidine protein kinase gene ciaH, resulting in enhanced gene expression mediated by the cognate response regulator CiaR. Deletion of htrA, encoding a serine protease regulated by CiaR, or inactivation of HtrA proteolytic activity showed that HtrA is indeed responsible for PBP2x degradation in both mutants, and that this affects β-lactam resistance. Depletion of the PBP2xC405 in different genetic backgrounds confirmed that HtrA degrades PBP2xC405. A GFP-PBP2xC405 fusion protein still localized at the septum in the absence of HtrA. The complementation studies in HtrA deletion strains showed that HtrA can be overexpressed in pneumococcal cells to specific levels, depending on the genetic background. Quantitative Western blotting revealed that the PBP2x amount in C405 strain was less than 20% compared to parental strain, suggesting that PBP2x is an abundant protein in S. pneumoniae R6 strain.
Collapse
|
13
|
Visualization and Analysis of the Dynamic Assembly of a Heterologous Lantibiotic Biosynthesis Complex in Bacillus subtilis. mBio 2021; 12:e0121921. [PMID: 34281399 PMCID: PMC8406302 DOI: 10.1128/mbio.01219-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A membrane-associated lanthipeptide synthetase complex, consisting of the dehydratase NisB, the cyclase NisC, and the ABC transporter NisT, has been described for nisin biosynthesis in the coccoid bacterium Lactococcus lactis. Here, we used advanced fluorescence microscopy to visualize the functional nisin biosynthesis machinery in rod-shaped cells and analyzed its spatial distribution and dynamics employing a platform we developed for heterologous production of nisin in Bacillus subtilis. We observed that NisT, as well as NisB and NisC, were all distributed in a punctate pattern along the cell periphery, opposed to the situation in coccoid cells. NisBTC proteins were found to be highly colocalized, being visualized at the same spots by dual fluorescence microscopy. In conjunction with the successful isolation of the biosynthetic complex NisBTC from the cell membrane, this corroborated that the visual bright foci were the sites for nisin maturation and transportation. A strategy of differential timing of expression was employed to demonstrate the in vivo dynamic assembly of NisBTC, revealing the recruitment by NisT of NisBC to the membrane. Additionally, by use of mutated proteins, the nucleotide binding domain (NBD) of NisT was found to function as a membrane anchor for NisB and/or NisC. We also show that the nisin biosynthesis sites are static and likely associated with proteins residing in lipid rafts. Based on these data, we propose a model for a three-phase production of modified precursor nisin in rod-shaped bacteria, presenting the assembly dynamics of NisBTC and emphasizing the crucial role of NisBC, next to NisT, in the process of precursor nisin translocation.
Collapse
|
14
|
Chao Y, Bergenfelz C, Sun R, Han X, Achour A, Hakansson AP. The serine protease HtrA plays a key role in heat-induced dispersal of pneumococcal biofilms. Sci Rep 2020; 10:22455. [PMID: 33384455 PMCID: PMC7775458 DOI: 10.1038/s41598-020-80233-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 12/17/2020] [Indexed: 12/28/2022] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) colonizes the human nasopharynx by forming multicellular biofilms. Due to the high level of asymptomatic carriage, transition to infections, such as otitis media, pneumonia, sepsis, and meningitis, occurs often enough that the pneumococcus remains a major cause of disease and death globally. Virus infection and virus-induced responses, such as increased temperature (fever), trigger release of virulent bacteria from colonizing biofilms. The exact mechanisms involved in pneumococcal egress during biofilm dispersal remain unknown, although we hypothesize that disruption of the biofilm matrix encasing the bacteria is necessary. Here, we utilized established in vitro biofilm dispersal models to investigate the involvement of proteases in bacterial egress from pneumococcal biofilms. We demonstrate the importance of protease activity, both through increased bacterial release following addition of proteases and reduced heat-induced biofilm dispersal in the presence of protease inhibitors. We identify a key role for the surface-exposed serine protease HtrA, but not PrtA, in heat-induced biofilm dispersal. Bacterial release from htrA-negative biofilms was significantly reduced compared to wild-type isogenic strains but was restored and increased above wild-type levels following addition of recombinant HtrA. Understanding the specific mechanisms involved in bacterial egress may provide novel targets for future strategies aimed to specifically interfere with disease progression without disturbing nasopharyngeal biofilm colonization.
Collapse
Affiliation(s)
- Yashuan Chao
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden.,Division of Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Caroline Bergenfelz
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Renhua Sun
- Science for Life Laboratory, Department of Medicine, Karolinska Institute, Solna, Sweden.,Division of Infectious Diseases, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Xiao Han
- Science for Life Laboratory, Department of Medicine, Karolinska Institute, Solna, Sweden.,Division of Infectious Diseases, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Adnane Achour
- Science for Life Laboratory, Department of Medicine, Karolinska Institute, Solna, Sweden.,Division of Infectious Diseases, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Anders P Hakansson
- Division of Experimental Infection Medicine, Department of Translational Medicine, Lund University, Malmö, Sweden.
| |
Collapse
|
15
|
Class A PBPs have a distinct and unique role in the construction of the pneumococcal cell wall. Proc Natl Acad Sci U S A 2020; 117:6129-6138. [PMID: 32123104 PMCID: PMC7084106 DOI: 10.1073/pnas.1917820117] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Peptidoglycan, the main structural component of the bacterial cell wall, is made of glycan strands cross-linked by short peptides. It has long been assumed that class A penicillin-binding proteins (PBPs) are the only enzymes capable of synthesizing glycan strands from lipid II. Recently, however, it was discovered that two non-PBP proteins, FtsW and RodA, constitute the core peptidoglycan polymerizing enzymes of the divisome and elongasome, respectively. What, then, is the role of class A PBPs in the construction of the bacterial cell wall? In contrast to previous assumptions, our results strongly suggest that class A PBPs are not an intrinsic part of the divisome and elongasome but have important autonomous roles in construction of the fully mature bacterial cell wall. In oval-shaped Streptococcus pneumoniae, septal and longitudinal peptidoglycan syntheses are performed by independent functional complexes: the divisome and the elongasome. Penicillin-binding proteins (PBPs) were long considered the key peptidoglycan-synthesizing enzymes in these complexes. Among these were the bifunctional class A PBPs, which are both glycosyltransferases and transpeptidases, and monofunctional class B PBPs with only transpeptidase activity. Recently, however, it was established that the monofunctional class B PBPs work together with transmembrane glycosyltransferases (FtsW and RodA) from the shape, elongation, division, and sporulation (SEDS) family to make up the core peptidoglycan-synthesizing machineries within the pneumococcal divisome (FtsW/PBP2x) and elongasome (RodA/PBP2b). The function of class A PBPs is therefore now an open question. Here we utilize the peptidoglycan hydrolase CbpD that targets the septum of S. pneumoniae cells to show that class A PBPs have an autonomous role during pneumococcal cell wall synthesis. Using assays to specifically inhibit the function of PBP2x and FtsW, we demonstrate that CbpD attacks nascent peptidoglycan synthesized by the divisome. Notably, class A PBPs could process this nascent peptidoglycan from a CbpD-sensitive to a CbpD-resistant form. The class A PBP-mediated processing was independent of divisome and elongasome activities. Class A PBPs thus constitute an autonomous functional entity which processes recently formed peptidoglycan synthesized by FtsW/PBP2×. Our results support a model in which mature pneumococcal peptidoglycan is synthesized by three functional entities, the divisome, the elongasome, and bifunctional PBPs. The latter modify existing peptidoglycan but are probably not involved in primary peptidoglycan synthesis.
Collapse
|
16
|
Liu Y, Zeng Y, Huang Y, Gu L, Wang S, Li C, Morrison DA, Deng H, Zhang JR. HtrA-mediated selective degradation of DNA uptake apparatus accelerates termination of pneumococcal transformation. Mol Microbiol 2019; 112:1308-1325. [PMID: 31396996 DOI: 10.1111/mmi.14364] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2019] [Indexed: 02/06/2023]
Abstract
Natural transformation mediates horizontal gene transfer, and thereby promotes exchange of antibiotic resistance and virulence traits among bacteria. Streptococcus pneumoniae, the first known transformable bacterium, rapidly activates and then terminates the transformation state, but it is unclear how the bacterium accomplishes this rapid turn-around at the protein level. This work determined the transcriptomic and proteomic dynamics during the window of pneumococcal transformation. RNA sequencing revealed a nearly uniform temporal pattern of rapid transcriptional activation and subsequent shutdown for the genes encoding transformation proteins. In contrast, mass spectrometry analysis showed that the majority of transformation proteins were substantially preserved beyond the window of transformation. However, ComEA and ComEC, major components of the DNA uptake apparatus for transformation, were completely degraded at the end of transformation. Further mutagenesis screening revealed that the membrane-associated serine protease HtrA mediates selective degradation of ComEA and ComEC, strongly suggesting that breakdown of the DNA uptake apparatus by HtrA is an important mechanism for termination of pneumococcal transformation. Finally, our mutagenesis analysis showed that HtrA inhibits natural transformation of Streptococcus mitis and Streptococcus gordonii. Together, this work has revealed that HtrA regulates the level and duration of natural transformation in multiple streptococcal species.
Collapse
Affiliation(s)
- Yanni Liu
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Yuna Zeng
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Yijia Huang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| | - Lixiao Gu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Shaolin Wang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Chunhao Li
- Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA
| | - Donald A Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Haiteng Deng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
| |
Collapse
|
17
|
Establishment of serine protease htrA mutants in Helicobacter pylori is associated with secA mutations. Sci Rep 2019; 9:11794. [PMID: 31409845 PMCID: PMC6692382 DOI: 10.1038/s41598-019-48030-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/29/2019] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori plays an essential role in the pathogenesis of gastritis, peptic ulcer disease, and gastric cancer. The serine protease HtrA, an important secreted virulence factor, disrupts the gastric epithelium, which enables H. pylori to transmigrate across the epithelium and inject the oncogenic CagA protein into host cells. The function of periplasmic HtrA for the H. pylori cell is unknown, mainly due to unavailability of the htrA mutants. In fact, htrA has been described as an essential gene in this bacterium. We have screened 100 worldwide H. pylori isolates and show that only in the N6 strain it was possible to delete htrA or mutate the htrA gene to produce proteolytically inactive HtrA. We have sequenced the wild-type and mutant chromosomes and we found that inactivation of htrA is associated with mutations in SecA – a component of the Sec translocon apparatus used to translocate proteins from the cytoplasm into the periplasm. The cooperation of SecA and HtrA has been already suggested in Streptococcus pneumonia, in which these two proteins co-localize. Hence, our results pinpointing a potential functional relationship between HtrA and the Sec translocon in H. pylori possibly indicate for the more general mechanism responsible to maintain bacterial periplasmic homeostasis.
Collapse
|
18
|
Yu W, Missiakas D, Schneewind O. Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis. eLife 2018; 7:34092. [PMID: 29757141 PMCID: PMC5962339 DOI: 10.7554/elife.34092] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/05/2018] [Indexed: 12/26/2022] Open
Abstract
Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and abolishes SpA precursor trafficking to septal membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.
Collapse
Affiliation(s)
- Wenqi Yu
- Department of Microbiology, University of Chicago, Chicago, United States
| | | | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, United States
| |
Collapse
|
19
|
Backert S, Bernegger S, Skórko-Glonek J, Wessler S. Extracellular HtrA serine proteases: An emerging new strategy in bacterial pathogenesis. Cell Microbiol 2018; 20:e12845. [PMID: 29582532 DOI: 10.1111/cmi.12845] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/20/2018] [Indexed: 12/18/2022]
Abstract
The HtrA family of chaperones and serine proteases is important for regulating stress responses and controlling protein quality in the periplasm of bacteria. HtrA is also associated with infectious diseases since inactivation of htrA genes results in significantly reduced virulence properties by various bacterial pathogens. These virulence features of HtrA can be attributed to reduced fitness of the bacteria, higher susceptibility to environmental stress and/or diminished secretion of virulence factors. In some Gram-negative and Gram-positive pathogens, HtrA itself can be exposed to the extracellular environment promoting bacterial colonisation and invasion of host tissues. Most of our knowledge on the function of exported HtrAs stems from research on Helicobacter pylori, Campylobacter jejuni, Borrelia burgdorferi, Bacillus anthracis, and Chlamydia species. Here, we discuss recent progress showing that extracellular HtrAs are able to cleave cell-to-cell junction factors including E-cadherin, occludin, and claudin-8, as well as extracellular matrix proteins such as fibronectin, aggrecan, and proteoglycans, disrupting the epithelial barrier and producing substantial host cell damage. We propose that the export of HtrAs is a newly discovered strategy, also applied by additional bacterial pathogens. Consequently, exported HtrA proteases represent highly attractive targets for antibacterial treatment by inhibiting their proteolytic activity or application in vaccine development.
Collapse
Affiliation(s)
- Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Sabine Bernegger
- Department of Biosciences, Division of Microbiology, Paris Lodron University of Salzburg, Salzburg, Austria
| | - Joanna Skórko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Silja Wessler
- Department of Biosciences, Division of Microbiology, Paris Lodron University of Salzburg, Salzburg, Austria
| |
Collapse
|
20
|
Abstract
Control and manipulation of bacterial populations requires an understanding of the factors that govern growth, division, and antibiotic action. Fluorescent and chemically reactive small molecule probes of cell envelope components can visualize these processes and advance our knowledge of cell envelope biosynthesis (e.g., peptidoglycan production). Still, fundamental gaps remain in our understanding of the spatial and temporal dynamics of cell envelope assembly. Previously described reporters require steps that limit their use to static imaging. Probes that can be used for real-time imaging would advance our understanding of cell envelope construction. To this end, we synthesized a fluorogenic probe that enables continuous live cell imaging in mycobacteria and related genera. This probe reports on the mycolyltransferases that assemble the mycolic acid membrane. This peptidoglycan-anchored bilayer-like assembly functions to protect these cells from antibiotics and host defenses. Our probe, quencher-trehalose-fluorophore (QTF), is an analog of the natural mycolyltransferase substrate. Mycolyltransferases process QTF by diverting their normal transesterification activity to hydrolysis, a process that unleashes fluorescence. QTF enables high contrast continuous imaging and the visualization of mycolyltransferase activity in cells. QTF revealed that mycolyltransferase activity is augmented before cell division and localized to the septa and cell poles, especially at the old pole. This observed localization suggests that mycolyltransferases are components of extracellular cell envelope assemblies, in analogy to the intracellular divisomes and polar elongation complexes. We anticipate QTF can be exploited to detect and monitor mycobacteria in physiologically relevant environments.
Collapse
|
21
|
Engholm DH, Kilian M, Goodsell DS, Andersen ES, Kjærgaard RS. A visual review of the human pathogen Streptococcus pneumoniae. FEMS Microbiol Rev 2018; 41:854-879. [PMID: 29029129 DOI: 10.1093/femsre/fux037] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 09/04/2017] [Indexed: 11/12/2022] Open
Abstract
Being the principal causative agent of bacterial pneumonia, otitis media, meningitis and septicemia, the bacterium Streptococcus pneumoniae is a major global health problem. To highlight the molecular basis of this problem, we have portrayed essential biological processes of the pneumococcal life cycle in eight watercolor paintings. The paintings are done to a consistent nanometer scale based on currently available data from structural biology and proteomics. In this review article, the paintings are used to provide a visual review of protein synthesis, carbohydrate metabolism, cell wall synthesis, cell division, teichoic acid synthesis, virulence, transformation and pilus synthesis based on the available scientific literature within the field of pneumococcal biology. Visualization of the molecular details of these processes reveals several scientific questions about how molecular components of the pneumococcal cell are organized to allow biological function to take place. By the presentation of this visual review, we intend to stimulate scientific discussion, aid in the generation of scientific hypotheses and increase public awareness. A narrated video describing the biological processes in the context of a whole-cell illustration accompany this article.
Collapse
Affiliation(s)
- Ditte Høyer Engholm
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Mogens Kilian
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - David S Goodsell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Rutgers, the State University of New Jersey, NJ 08901, USA
| | - Ebbe Sloth Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark.,Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus, Denmark
| | | |
Collapse
|
22
|
Rashid R, Cazenave-Gassiot A, Gao IH, Nair ZJ, Kumar JK, Gao L, Kline KA, Wenk MR. Comprehensive analysis of phospholipids and glycolipids in the opportunistic pathogen Enterococcus faecalis. PLoS One 2017; 12:e0175886. [PMID: 28423018 PMCID: PMC5397010 DOI: 10.1371/journal.pone.0175886] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 04/02/2017] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis is a Gram-positive, opportunistic, pathogenic bacterium that causes a significant number of antibiotic-resistant infections in hospitalized patients. The development of antibiotic resistance in hospital-associated pathogens is a formidable public health threat. In E. faecalis and other Gram-positive pathogens, correlations exist between lipid composition and antibiotic resistance. Resistance to the last-resort antibiotic daptomycin is accompanied by a decrease in phosphatidylglycerol (PG) levels, whereas multiple peptide resistance factor (MprF) converts anionic PG into cationic lysyl-PG via a trans-esterification reaction, providing resistance to cationic antimicrobial peptides. Unlike previous studies that relied on thin layer chromatography and spectrophotometry, we have performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) directly on lipids extracted from E. faecalis, and quantified the phospholipids through multiple reaction monitoring (MRM). In the daptomycin-sensitive E. faecalis strain OG1RF, we have identified 17 PGs, 8 lysyl-PGs (LPGs), 23 cardiolipins (CL), 3 glycerophospho-diglucosyl-diacylglycerols (GPDGDAG), 5 diglucosyl-diacylglycerols (DGDAG), 3 diacylglycerols (DAGs), and 4 triacylglycerols (TAGs). We have quantified PG and shown that PG levels vary during growth of E. faecalis in vitro. We also show that two daptomycin-resistant (DapR) strains of E. faecalis have substantially lower levels of PG and LPG levels. Since LPG levels in these strains are lower, daptomycin resistance is likely due to the reduction in PG. This lipidome map is the first comprehensive analysis of membrane phospholipids and glycolipids in the important human pathogen E. faecalis, for which antimicrobial resistance and altered lipid homeostasis have been intimately linked.
Collapse
Affiliation(s)
- Rafi Rashid
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Amaury Cazenave-Gassiot
- Singapore Lipidomics Incubator, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Iris H. Gao
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Zeus J. Nair
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jaspal K. Kumar
- Singapore Lipidomics Incubator, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Liang Gao
- Singapore Lipidomics Incubator, National University of Singapore, Singapore, Singapore
- Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Kimberly A. Kline
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail: (KAK); (MRW)
| | - Markus R. Wenk
- Singapore Lipidomics Incubator, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
- * E-mail: (KAK); (MRW)
| |
Collapse
|
23
|
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] [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.
Collapse
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
| |
Collapse
|
24
|
Dajkovic A, Hinde E, MacKichan C, Carballido-Lopez R. Dynamic Organization of SecA and SecY Secretion Complexes in the B. subtilis Membrane. PLoS One 2016; 11:e0157899. [PMID: 27336478 PMCID: PMC4918944 DOI: 10.1371/journal.pone.0157899] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/07/2016] [Indexed: 12/21/2022] Open
Abstract
In prokaryotes, about one third of cellular proteins are translocated across the plasma membrane or inserted into it by concerted action of the cytoplasmic ATPase SecA and the universally conserved SecYEG heterotrimeric polypeptide-translocating pore. Secretion complexes have been reported to localize in specific subcellular sites in Bacillus subtilis. In this work, we used a combination of total internal reflection microscopy, scanning fluorescence correlation spectroscopy, and pair correlation function to study the localization and dynamics of SecA and SecY in growing Bacillus subtilis cells. Both SecA and SecY localized in transient and dynamic foci in the cytoplasmic membrane, which displayed no higher-level organization in helices. Foci of SecA and SecY were in constant flux with freely diffusing SecA and SecY molecules. Scanning FCS confirmed the existence of populations of cellular SecA and SecY molecules with a wide range of diffusion coefficients. Diffusion of SecY as an uncomplexed molecular species was short-lived and only local while SecY complexed with its protein partners traversed distances of over half a micrometer in the cell.
Collapse
Affiliation(s)
- Alex Dajkovic
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
- * E-mail:
| | - Elizabeth Hinde
- School of Medical Sciences, University of New South Wales, Sydney, Australia 2052
| | - Calum MacKichan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Rut Carballido-Lopez
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| |
Collapse
|
25
|
Mitra SD, Afonina I, Kline KA. Right Place, Right Time: Focalization of Membrane Proteins in Gram-Positive Bacteria. Trends Microbiol 2016; 24:611-621. [PMID: 27117048 DOI: 10.1016/j.tim.2016.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/03/2016] [Accepted: 03/24/2016] [Indexed: 11/25/2022]
Abstract
Membrane proteins represent a significant proportion of total bacterial proteins and perform vital cellular functions ranging from exchanging metabolites and genetic material, secretion and sorting, sensing signal molecules, and cell division. Many of these functions are carried out at distinct foci on the bacterial membrane, and this subcellular localization can be coordinated by a number of factors, including lipid microdomains, protein-protein interactions, and membrane curvature. Elucidating the mechanisms behind focal protein localization in bacteria informs not only protein structure-function correlation, but also how to disrupt the protein function to limit virulence. Here we review recent advances describing a functional role for subcellular localization of membrane proteins involved in genetic transfer, secretion and sorting, cell division and growth, and signaling.
Collapse
Affiliation(s)
- Sumitra D Mitra
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Irina Afonina
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
| |
Collapse
|
26
|
Spatial Organization of Cell Wall-Anchored Proteins at the Surface of Gram-Positive Bacteria. Curr Top Microbiol Immunol 2016; 404:177-201. [DOI: 10.1007/82_2016_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
27
|
Kopečná J, Pilný J, Krynická V, Tomčala A, Kis M, Gombos Z, Komenda J, Sobotka R. Lack of Phosphatidylglycerol Inhibits Chlorophyll Biosynthesis at Multiple Sites and Limits Chlorophyllide Reutilization in Synechocystis sp. Strain PCC 6803. PLANT PHYSIOLOGY 2015; 169:1307-17. [PMID: 26269547 PMCID: PMC4587476 DOI: 10.1104/pp.15.01150] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/11/2015] [Indexed: 05/20/2023]
Abstract
The negatively charged lipid phosphatidylglycerol (PG) constitutes up to 10% of total lipids in photosynthetic membranes, and its deprivation in cyanobacteria is accompanied by chlorophyll (Chl) depletion. Indeed, radioactive labeling of the PG-depleted ΔpgsA mutant of Synechocystis sp. strain PCC 6803, which is not able to synthesize PG, proved the inhibition of Chl biosynthesis caused by restriction on the formation of 5-aminolevulinic acid and protochlorophyllide. Although the mutant accumulated chlorophyllide, the last Chl precursor, we showed that it originated from dephytylation of existing Chl and not from the block in the Chl biosynthesis. The lack of de novo-produced Chl under PG depletion was accompanied by a significantly weakened biosynthesis of both monomeric and trimeric photosystem I (PSI) complexes, although the decrease in cellular content was manifested only for the trimeric form. However, our analysis of ΔpgsA mutant, which lacked trimeric PSI because of the absence of the PsaL subunit, suggested that the virtual stability of monomeric PSI is a result of disintegration of PSI trimers. Interestingly, the loss of trimeric PSI was accompanied by accumulation of monomeric PSI associated with the newly synthesized CP43 subunit of photosystem II. We conclude that the absence of PG results in the inhibition of Chl biosynthetic pathway, which impairs synthesis of PSI, despite the accumulation of chlorophyllide released from the degraded Chl proteins. Based on the knowledge about the role of PG in prokaryotes, we hypothesize that the synthesis of Chl and PSI complexes are colocated in a membrane microdomain requiring PG for integrity.
Collapse
Affiliation(s)
- Jana Kopečná
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Jan Pilný
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Vendula Krynická
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Aleš Tomčala
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Mihály Kis
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Zoltan Gombos
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Josef Komenda
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| | - Roman Sobotka
- Institute of Microbiology, Centre Algatech, 37981 Trebon, Czech Republic (J.Kop., J.P., V.K., J.Kom., R.S.);Faculty of Science, University of South Bohemia, 37005 Ceske Budejovice, Czech Republic (V.K., A.T., J.Kom., R.S.);Biology Centre, Institute of Parasitology, 37005 Ceske Budejovice, Czech Republic (A.T.); andInstitute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary (M.K., Z.G.)
| |
Collapse
|
28
|
Minimal Peptidoglycan (PG) Turnover in Wild-Type and PG Hydrolase and Cell Division Mutants of Streptococcus pneumoniae D39 Growing Planktonically and in Host-Relevant Biofilms. J Bacteriol 2015; 197:3472-85. [PMID: 26303829 DOI: 10.1128/jb.00541-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/15/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED We determined whether there is turnover of the peptidoglycan (PG) cell wall of the ovococcus bacterial pathogen Streptococcus pneumoniae (pneumococcus). Pulse-chase experiments on serotype 2 strain D39 radiolabeled with N-acetylglucosamine revealed little turnover and release of PG breakdown products during growth compared to published reports of PG turnover in Bacillus subtilis. PG dynamics were visualized directly by long-pulse-chase-new-labeling experiments using two colors of fluorescent d-amino acid (FDAA) probes to microscopically detect regions of new PG synthesis. Consistent with minimal PG turnover, hemispherical regions of stable "old" PG persisted in D39 and TIGR4 (serotype 4) cells grown in rich brain heart infusion broth, in D39 cells grown in chemically defined medium containing glucose or galactose as the carbon source, and in D39 cells grown as biofilms on a layer of fixed human epithelial cells. In contrast, B. subtilis exhibited rapid sidewall PG turnover in similar FDAA-labeling experiments. High-performance liquid chromatography (HPLC) analysis of biochemically released peptides from S. pneumoniae PG validated that FDAAs incorporated at low levels into pentamer PG peptides and did not change the overall composition of PG peptides. PG dynamics were also visualized in mutants lacking PG hydrolases that mediate PG remodeling, cell separation, or autolysis and in cells lacking the MapZ and DivIVA division regulators. In all cases, hemispheres of stable old PG were maintained. In PG hydrolase mutants exhibiting aberrant division plane placement, FDAA labeling revealed patches of inert PG at turns and bulge points. We conclude that growing S. pneumoniae cells exhibit minimal PG turnover compared to the PG turnover in rod-shaped cells. IMPORTANCE PG cell walls are unique to eubacteria, and many bacterial species turn over and recycle their PG during growth, stress, colonization, and virulence. Consequently, PG breakdown products serve as signals for bacteria to induce antibiotic resistance and as activators of innate immune responses. S. pneumoniae is a commensal bacterium that colonizes the human nasopharynx and opportunistically causes serious respiratory and invasive diseases. The results presented here demonstrate a distinct demarcation between regions of old PG and regions of new PG synthesis and minimal turnover of PG in S. pneumoniae cells growing in culture or in host-relevant biofilms. These findings suggest that S. pneumoniae minimizes the release of PG breakdown products by turnover, which may contribute to evasion of the innate immune system.
Collapse
|
29
|
Matsumoto K, Hara H, Fishov I, Mileykovskaya E, Norris V. The membrane: transertion as an organizing principle in membrane heterogeneity. Front Microbiol 2015; 6:572. [PMID: 26124753 PMCID: PMC4464175 DOI: 10.3389/fmicb.2015.00572] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/25/2015] [Indexed: 01/05/2023] Open
Abstract
The bacterial membrane exhibits a significantly heterogeneous distribution of lipids and proteins. This heterogeneity results mainly from lipid-lipid, protein-protein, and lipid-protein associations which are orchestrated by the coupled transcription, translation and insertion of nascent proteins into and through membrane (transertion). Transertion is central not only to the individual assembly and disassembly of large physically linked groups of macromolecules (alias hyperstructures) but also to the interactions between these hyperstructures. We review here these interactions in the context of the processes in Bacillus subtilis and Escherichia coli of nutrient sensing, membrane synthesis, cytoskeletal dynamics, DNA replication, chromosome segregation, and cell division.
Collapse
Affiliation(s)
- Kouji Matsumoto
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, SaitamaJapan
| | - Hiroshi Hara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, SaitamaJapan
| | - Itzhak Fishov
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-ShevaIsrael
| | - Eugenia Mileykovskaya
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at HoustonHouston, TX, USA
| | - Vic Norris
- Laboratory of Microbiology Signals and Microenvironment EA 4312, Department of Science, University of Rouen, Mont-Saint-AignanFrance
| |
Collapse
|
30
|
The essential features and modes of bacterial polar growth. Trends Microbiol 2015; 23:347-53. [PMID: 25662291 DOI: 10.1016/j.tim.2015.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/19/2014] [Accepted: 01/07/2015] [Indexed: 01/25/2023]
Abstract
Polar growth represents a surprising departure from the canonical dispersed cell growth model. However, we know relatively little of the underlying mechanisms governing polar growth or the requisite suite of factors that direct polar growth. Underscoring how classic doctrine can be turned on its head, the peptidoglycan layer of polar-growing bacteria features unusual crosslinks and in some species the quintessential cell division proteins FtsA and FtsZ are recruited to the growing poles. Remarkably, numerous medically important pathogens utilize polar growth, accentuating the need for intensive research in this area. Here we review models of polar growth in bacteria based on recent research in the Actinomycetales and Rhizobiales, with emphasis on Mycobacterium and Agrobacterium species.
Collapse
|
31
|
Lewis NE, Brady LJ. Breaking the bacterial protein targeting and translocation model: oral organisms as a case in point. Mol Oral Microbiol 2014; 30:186-97. [PMID: 25400073 DOI: 10.1111/omi.12088] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2014] [Indexed: 12/19/2022]
Abstract
Insights into the membrane biogenesis of oral and throat bacteria have highlighted key differences in protein localization by the general secretion pathway compared with the well-studied Escherichia coli model system. These intriguing novelties have advanced our understanding of both how these microorganisms have adapted to survive and cause disease in the oral cavity, and the field of protein translocation as a whole. This review focuses on findings that highlight where oral bacteria differ from the E. coli paradigm, why these differences are biologically important, and what questions remain about the differences in pathway function. The majority of insight into protein translocation in microbes of the oral cavity has come from streptococcal species, which will be the main topic of this review. However, other bacteria will be discussed when relevant. An overview of the E. coli model of protein targeting and translocation is provided for comparison.
Collapse
Affiliation(s)
- N E Lewis
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | | |
Collapse
|
32
|
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 PMCID: PMC4209751 DOI: 10.1111/mmi.12745] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
Collapse
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
| |
Collapse
|
33
|
Schneewind O, Missiakas D. Sec-secretion and sortase-mediated anchoring of proteins in Gram-positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:1687-97. [PMID: 24269844 PMCID: PMC4031296 DOI: 10.1016/j.bbamcr.2013.11.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/01/2013] [Accepted: 11/13/2013] [Indexed: 01/17/2023]
Abstract
Signal peptide-driven secretion of precursor proteins directs polypeptides across the plasma membrane of bacteria. Two pathways, Sec- and SRP-dependent, converge at the SecYEG translocon to thread unfolded precursor proteins across the membrane, whereas folded preproteins are routed via the Tat secretion pathway. Gram-positive bacteria lack an outer membrane and are surrounded by a rigid layer of peptidoglycan. Interactions with their environment are mediated by proteins that are retained in the cell wall, often through covalent attachment to the peptidoglycan. In this review, we describe the mechanisms for both Sec-dependent secretion and sortase-dependent assembly of proteins in the envelope of Gram-positive bacteria. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
Collapse
Affiliation(s)
- Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA.
| | | |
Collapse
|
34
|
Abstract
In the past decade, Clostridium difficile has emerged as an important gut pathogen. Symptoms of C. difficile infection range from mild diarrhea to pseudomembranous colitis. Besides the two main virulence factors toxin A and toxin B, other virulence factors are likely to play a role in the pathogenesis of the disease. In other Gram-positive and Gram-negative pathogenic bacteria, conserved high-temperature requirement A (HtrA)-like proteases have been shown to have a role in protein homeostasis and quality control. This affects the functionality of virulence factors and the resistance of bacteria to (host-induced) environmental stresses. We found that the C. difficile 630 genome encodes a single HtrA-like protease (CD3284; HtrA) and have analyzed its role in vivo and in vitro through the creation of an isogenic ClosTron-based htrA mutant of C. difficile strain 630Δerm (wild type). In contrast to the attenuated phenotype seen with htrA deletion in other pathogens, this mutant showed enhanced virulence in the Golden Syrian hamster model of acute C. difficile infection. Microarray data analysis showed a pleiotropic effect of htrA on the transcriptome of C. difficile, including upregulation of the toxin A gene. In addition, the htrA mutant showed reduced spore formation and adherence to colonic cells. Together, our data show that htrA can modulate virulence in C. difficile.
Collapse
|
35
|
Schweizer I, Peters K, Stahlmann C, Hakenbeck R, Denapaite D. Penicillin-binding protein 2x of Streptococcus pneumoniae: the mutation Ala707Asp within the C-terminal PASTA2 domain leads to destabilization. Microb Drug Resist 2014; 20:250-7. [PMID: 24841912 DOI: 10.1089/mdr.2014.0082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Streptococcus pneumoniae penicillin-binding protein 2x (PBP2x) is an enzyme involved in the last stages of peptidoglycan assembly and essential for bacterial growth and survival. PBP2x localizes to the division site, a process that depends on its Penicillin-Binding Protein And Serine-Threonine-kinase Associated (PASTA) domains, which was previously demonstrated via GFP-PBP2x in living cells. During this study a mutant strain was isolated in which the GFP-PBP2x fusion protein did not localize at division sites and it contained reduced amounts of the full-length GFP-PBP2x. We now show that this defect is due to a point mutation within the C-terminal PASTA2 domain of PBP2x. The mutant protein was analyzed in detail in terms of beta-lactam binding, functionality, and localization in live cells. We demonstrate that the mutation affects the GFP-tagged PBP2x variant severely and renders it susceptible to the protease/chaperone HtrA.
Collapse
Affiliation(s)
- Inga Schweizer
- Department of Microbiology, University of Kaiserslautern , Kaiserslautern, Germany
| | | | | | | | | |
Collapse
|
36
|
Peters K, Schweizer I, Beilharz K, Stahlmann C, Veening JW, Hakenbeck R, Denapaite D. Streptococcus pneumoniae PBP2x mid-cell localization requires the C-terminal PASTA domains and is essential for cell shape maintenance. Mol Microbiol 2014; 92:733-55. [DOI: 10.1111/mmi.12588] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Katharina Peters
- Department of Microbiology; University of Kaiserslautern; Paul-Ehrlich Straße 23 D-67663 Kaiserslautern Germany
| | - Inga Schweizer
- Department of Microbiology; University of Kaiserslautern; Paul-Ehrlich Straße 23 D-67663 Kaiserslautern Germany
| | - Katrin Beilharz
- Molecular Genetics Group; Groningen Biomolecular Sciences and Biotechnology Institute; Centre for Synthetic Biology; University of Groningen; Nijenborgh 7 9747 AG Groningen The Netherlands
| | - Christoph Stahlmann
- Department of Microbiology; University of Kaiserslautern; Paul-Ehrlich Straße 23 D-67663 Kaiserslautern Germany
| | - Jan-Willem Veening
- Molecular Genetics Group; Groningen Biomolecular Sciences and Biotechnology Institute; Centre for Synthetic Biology; University of Groningen; Nijenborgh 7 9747 AG Groningen The Netherlands
| | - Regine Hakenbeck
- Department of Microbiology; University of Kaiserslautern; Paul-Ehrlich Straße 23 D-67663 Kaiserslautern Germany
- Stiftung Alfried Krupp Kolleg Greifswald; D-17487 Greifswald Germany
| | - Dalia Denapaite
- Department of Microbiology; University of Kaiserslautern; Paul-Ehrlich Straße 23 D-67663 Kaiserslautern Germany
| |
Collapse
|
37
|
Revilla-Guarinos A, Alcántara C, Rozès N, Voigt B, Zúñiga M. Characterization of the response to low pH of Lactobacillus casei
ΔRR12, a mutant strain with low D-alanylation activity and sensitivity to low pH. J Appl Microbiol 2014; 116:1250-61. [DOI: 10.1111/jam.12442] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 11/08/2013] [Accepted: 01/06/2014] [Indexed: 01/08/2023]
Affiliation(s)
- A. Revilla-Guarinos
- Dpto. Biotecnología de Alimentos; Consejo Superior de Investigaciones Científicas (CSIC); Instituto de Agroquímica y Tecnología de Alimentos (IATA); Paterna Valencia Spain
| | - C. Alcántara
- Dpto. Biotecnología de Alimentos; Consejo Superior de Investigaciones Científicas (CSIC); Instituto de Agroquímica y Tecnología de Alimentos (IATA); Paterna Valencia Spain
| | - N. Rozès
- Dpt. Bioquímica i Biotecnología; Facultat d'Enologia; Universitat Rovira i Virgili; Tarragona Spain
| | - B. Voigt
- Institute for Microbiology; University of Greifswald; Greifswald Germany
| | - M. Zúñiga
- Dpto. Biotecnología de Alimentos; Consejo Superior de Investigaciones Científicas (CSIC); Instituto de Agroquímica y Tecnología de Alimentos (IATA); Paterna Valencia Spain
| |
Collapse
|
38
|
Woappi Y, Gabani P, Singh A, Singh OV. Antibiotrophs: The complexity of antibiotic-subsisting and antibiotic-resistant microorganisms. Crit Rev Microbiol 2014; 42:17-30. [PMID: 24495094 DOI: 10.3109/1040841x.2013.875982] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Widespread overuse of antibiotics has led to the emergence of numerous antibiotic-resistant bacteria; among these are antibiotic-subsisting strains capable of surviving in environments with antibiotics as the sole carbon source. This unparalleled expansion of antibiotic resistance reveals the potent and diversified resistance abilities of certain bacterial strains. Moreover, these strains often possess hypermutator phenotypes and virulence transmissibility competent for genomic and proteomic propagation and pathogenicity. Pragmatic and prospicient approaches will be necessary to develop efficient therapeutic methods against such bacteria and to understand the extent of their genomic adaptability. This review aims to reveal the niches of these antibiotic-catabolizing microbes and assesses the underlying factors linking natural microbial antibiotic production, multidrug resistance, and antibiotic-subsistence.
Collapse
Affiliation(s)
- Yvon Woappi
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Prashant Gabani
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Arya Singh
- b Department of Computer Science , Texas State University , San Marcos , TX , USA
| | - Om V Singh
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| |
Collapse
|
39
|
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 PMCID: PMC4120849 DOI: 10.1111/mmi.12408] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
Collapse
Affiliation(s)
- Adrian D. Land
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Ho-Ching T. Tsui
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Ozden Kocaoglu
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
| | - Stephen A. Vella
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Sidney L. Shaw
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Susan K. Keen
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
| | - Lok-To Sham
- 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
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN 47405
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, IN 47405
| |
Collapse
|
40
|
Salzano AM, Novi G, Arioli S, Corona S, Mora D, Scaloni A. Mono-dimensional blue native-PAGE and bi-dimensional blue native/urea-PAGE or/SDS-PAGE combined with nLC–ESI-LIT-MS/MS unveil membrane protein heteromeric and homomeric complexes in Streptococcus thermophilus. J Proteomics 2013; 94:240-61. [DOI: 10.1016/j.jprot.2013.09.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/04/2013] [Accepted: 09/14/2013] [Indexed: 02/06/2023]
|
41
|
de Stoppelaar SF, Bootsma HJ, Zomer A, Roelofs JJTH, Hermans PWM, van ’t Veer C, van der Poll T. Streptococcus pneumoniae serine protease HtrA, but not SFP or PrtA, is a major virulence factor in pneumonia. PLoS One 2013; 8:e80062. [PMID: 24244609 PMCID: PMC3823867 DOI: 10.1371/journal.pone.0080062] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 10/08/2013] [Indexed: 12/11/2022] Open
Abstract
Streptococcus (S.) pneumoniae is a common causative pathogen in pneumonia. Serine protease orthologs expressed by a variety of bacteria have been found of importance for virulence. Previous studies have identified two serine proteases in S. pneumoniae, HtrA (high-temperature requirement A) and PrtA (cell wall-associated serine protease A), that contributed to virulence in models of pneumonia and intraperitoneal infection respectively. We here sought to identify additional S. pneumoniae serine proteases and determine their role in virulence. The S. pneumoniae D39 genome contains five putative serine proteases, of which HtrA, Subtilase Family Protein (SFP) and PrtA were selected for insertional mutagenesis because they are predicted to be secreted and surface exposed. Mutant D39 strains lacking serine proteases were constructed by in-frame insertion deletion mutagenesis. Pneumonia was induced by intranasal infection of mice with wild-type or mutant D39. After high dose infection, only D39ΔhtrA showed reduced virulence, as reflected by strongly reduced bacterial loads, diminished dissemination and decreased lung inflammation. D39ΔprtA induced significantly less lung inflammation together with smaller infiltrated lung surface, but without influencing bacterial loads. After low dose infection, D39ΔhtrA again showed strongly reduced bacterial loads; notably, pneumococcal burdens were also modestly lower in lungs after infection with D39Δsfp. These data confirm the important role for HtrA in S. pneumoniae virulence. PrtA contributes to lung damage in high dose pneumonia; it does not however contribute to bacterial outgrowth in pneumococcal pneumonia. SFP may facilitate S. pneumoniae growth after low dose infection.
Collapse
Affiliation(s)
- Sacha F. de Stoppelaar
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- * E-mail:
| | - Hester J. Bootsma
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Aldert Zomer
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
- Center for Molecular and Biomolecular Informatics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joris J. T. H. Roelofs
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter W. M. Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cornelis van ’t Veer
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Tom van der Poll
- Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Center for Experimental and Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Division of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
42
|
Focal targeting by human β-defensin 2 disrupts localized virulence factor assembly sites in Enterococcus faecalis. Proc Natl Acad Sci U S A 2013; 110:20230-5. [PMID: 24191013 DOI: 10.1073/pnas.1319066110] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Virulence factor secretion and assembly occurs at spatially restricted foci in some Gram-positive bacteria. Given the essentiality of the general secretion pathway in bacteria and the contribution of virulence factors to disease progression, the foci that coordinate these processes are attractive antimicrobial targets. In this study, we show in Enterococcus faecalis that SecA and Sortase A, required for the attachment of virulence factors to the cell wall, localize to discrete domains near the septum or nascent septal site as the bacteria proceed through the cell cycle. We also demonstrate that cationic human β-defensins interact with E. faecalis at discrete septal foci, and this exposure disrupts sites of localized secretion and sorting. Modification of anionic lipids by multiple peptide resistance factor, a protein that confers antimicrobial peptide resistance by electrostatic repulsion, renders E. faecalis more resistant to killing by defensins and less susceptible to focal targeting by the cationic antimicrobial peptides. These data suggest a paradigm in which focal targeting by antimicrobial peptides is linked to their killing efficiency and to disruption of virulence factor assembly.
Collapse
|
43
|
Carroll IM, Ringel-Kulka T, Ferrier L, Wu MC, Siddle JP, Bueno L, Ringel Y. Fecal protease activity is associated with compositional alterations in the intestinal microbiota. PLoS One 2013; 8:e78017. [PMID: 24147109 PMCID: PMC3798377 DOI: 10.1371/journal.pone.0078017] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 09/16/2013] [Indexed: 12/23/2022] Open
Abstract
Objective Intestinal proteases carry out a variety of functions in the gastrointestinal (GI) tract. Studies have reported that elevated enteric proteases in patients with GI disease can alter intestinal physiology, however the origin (human vs. microbial) of elevated proteases in patients with GI disease is unclear. Aim The aim of this study was to investigate the association between protease activity and the microbiota in human fecal samples. Design In order to capture a wide range of fecal protease (FP) activity stool samples were collected from 30 IBS patients and 24 healthy controls. The intestinal microbiota was characterized using 454 high throughput pyro-sequencing of the 16S rRNA gene. The composition and diversity of microbial communities were determined and compared using the Quantitative Insights Into Microbial Ecology (QIIME) pipeline. FP activity levels were determined using an ELISA-based method. FP activity was ranked and top and bottom quartiles (n=13 per quartile) were identified as having high and low FP activity, respectively. Results The overall diversity of the intestinal microbiota displayed significant clustering separation (p = 0.001) between samples with high vs. low FP activity. The Lactobacillales, Lachnospiraceae, and Streptococcaceae groups were positively associated with FP activity across the entire study population, whilst the Ruminococcaceae family and an unclassified Coriobacteriales family were negatively associated with FP activity. Conclusions These data demonstrate significant associations between specific intestinal bacterial groups and fecal protease activity and provide a basis for further causative studies investigating the role of enteric microbes and GI diseases.
Collapse
Affiliation(s)
- Ian M. Carroll
- Division of Gastroenterology and Hepatology, Department of Medicine, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Tamar Ringel-Kulka
- Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Laurent Ferrier
- INRA, UMR1331 Toxalim, Neuro-Gastroenterology & Nutrition group, Toulouse, France
| | - Michael C. Wu
- Department of Biostatistics, Gillings School of Global Public Health, the University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jennica P. Siddle
- Division of Gastroenterology and Hepatology, Department of Medicine, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Lionel Bueno
- INRA, UMR1331 Toxalim, Neuro-Gastroenterology & Nutrition group, Toulouse, France
| | - Yehuda Ringel
- Division of Gastroenterology and Hepatology, Department of Medicine, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
44
|
An association between peptidoglycan synthesis and organization of the Streptococcus pyogenes ExPortal. mBio 2013; 4:e00485-13. [PMID: 24065630 PMCID: PMC3781834 DOI: 10.1128/mbio.00485-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ExPortal of Streptococcus pyogenes is a focal microdomain of the cytoplasmic membrane that clusters the translocons of the general secretory pathway with accessory factors to facilitate the maturation of secreted polypeptides. While it is known that the ExPortal is enriched in anionic lipids, the mechanisms that organize the ExPortal are poorly understood. In the present study, we examined the role of the cell wall in organizing and maintaining the ExPortal. Removal of the cell wall resulted in a loss of ExPortal focal integrity accompanied by the circumferential redistribution of ExPortal lipid and protein components. A similar loss occurred upon treatment with gallidermin, a nonpermeabilizing lantibiotic that targets the lipid II precursor of peptidoglycan synthesis, and this treatment disrupted the secretion of several ExPortal substrates. Furthermore, several enzymes involved in the membrane-associated steps of lipid II synthesis, including MraY and MurN, were found to localize to a single discrete focus in the membrane that was coincident with the focal location of the secretory translocons and the anionic lipid microdomain. These data suggest that the ExPortal is associated with the site of peptidoglycan precursor synthesis and that peptidoglycan biogenesis influences ExPortal organization. These data add to an emerging literature indicating that cell wall biogenesis, cell division, and protein secretion are spatially coorganized processes. Since Gram-positive bacteria lack a periplasmic space, they lack a protected compartment to spatially coordinate interaction between newly secreted proteins and the factors required to process them. This represents a significant problem for pathogens that depend on the secretion of toxins and cell wall-associated adhesins to cause disease. Streptococci solve this dilemma by restricting secretion and processing factors to a defined region of the membrane. However, the mechanisms that promote restriction are not understood. In this study, we show that restriction of these factors in the pathogen Streptococcus pyogenes is intimately linked with the presence of the cell wall and its synthesis. Furthermore, several cell wall synthesis proteins are also restricted to the site of protein secretion. This study contributes to our understanding of how the Gram-positive cell is organized to coordinate protein secretion and biogenesis with cell wall synthesis and to the ongoing development of antibiotics that target these processes.
Collapse
|
45
|
Gagne AL, Stevens KE, Cassone M, Pujari A, Abiola OE, Chang DJ, Sebert ME. Competence in Streptococcus pneumoniae is a response to an increasing mutational burden. PLoS One 2013; 8:e72613. [PMID: 23967325 PMCID: PMC3742669 DOI: 10.1371/journal.pone.0072613] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/11/2013] [Indexed: 12/22/2022] Open
Abstract
Competence for genetic transformation in Streptococcus pneumoniae has previously been described as a quorum-sensing trait regulated by a secreted peptide pheromone. Recently we demonstrated that competence is also activated by reduction in the accuracy of protein biosynthesis. We have now investigated whether errors upstream of translation in the form of random genomic mutations can provide a similar stimulus. Here we show that generation of a mutator phenotype in S. pneumoniae through deletions of mutX, hexA or hexB enhanced the expression of competence. Similarly, chemical mutagenesis with the nucleotide analog dPTP promoted development of competence. To investigate the relationship between mutational load and the activation of competence, replicate lineages of the mutX strain were serially passaged under conditions of relaxed selection allowing random accumulation of secondary mutations. Competence increased with propagation in these lineages but not in control lineages having wild-type mutX. Resequencing of these derived strains revealed between 1 and 9 single nucleotide polymorphisms (SNPs) per lineage, which were broadly distributed across the genome and did not involve known regulators of competence. Notably, the frequency of competence development among the sequenced strains correlated significantly with the number of nonsynonymous mutations that had been acquired. Together, these observations provide support for the hypothesis that competence in S. pneumoniae is regulated in response to the accumulated burden of coding mutations in the bacterial genome. In contrast to previously described DNA damage response systems that are activated by physical lesions in the chromosome, this pneumococcal pathway may represent a unique stress response system that monitors the coding integrity of the genome.
Collapse
Affiliation(s)
- Alyssa L. Gagne
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Kathleen E. Stevens
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Marco Cassone
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Amit Pujari
- School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Olufunke E. Abiola
- School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Diana J. Chang
- School of Arts and Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michael E. Sebert
- Division of Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
46
|
Massidda O, Nováková L, Vollmer W. From models to pathogens: how much have we learned about Streptococcus pneumoniae cell division? Environ Microbiol 2013; 15:3133-57. [PMID: 23848140 DOI: 10.1111/1462-2920.12189] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/08/2013] [Accepted: 06/09/2013] [Indexed: 12/22/2022]
Abstract
Streptococcus pneumoniae is an oval-shaped Gram-positive coccus that lives in intimate association with its human host, both as a commensal and pathogen. The seriousness of pneumococcal infections and the spread of multi-drug resistant strains call for new lines of intervention. Bacterial cell division is an attractive target to develop antimicrobial drugs. This review discusses the recent advances in understanding S. pneumoniae growth and division, in comparison with the best studied rod-shaped models, Escherichia coli and Bacillus subtilis. To maintain their shape, these bacteria propagate by peripheral and septal peptidoglycan synthesis, involving proteins that assemble into distinct complexes called the elongasome and the divisome, respectively. Many of these proteins are conserved in S. pneumoniae, supporting the notion that the ovococcal shape is also achieved by rounds of elongation and division. Importantly, S. pneumoniae and close relatives with similar morphology differ in several aspects from the model rods. Overall, the data support a model in which a single large machinery, containing both the peripheral and septal peptidoglycan synthesis complexes, assembles at midcell and governs growth and division. The mechanisms generating the ovococcal or coccal shape in lactic-acid bacteria have likely evolved by gene reduction from a rod-shaped ancestor of the same group.
Collapse
Affiliation(s)
- Orietta Massidda
- Department of Surgical Sciences, University of Cagliari, Via Porcell, 4, 09100, Cagliari, Italy
| | | | | |
Collapse
|
47
|
Brega S, Caliot E, Trieu-Cuot P, Dramsi S. SecA localization and SecA-dependent secretion occurs at new division septa in group B Streptococcus. PLoS One 2013; 8:e65832. [PMID: 23762438 PMCID: PMC3676364 DOI: 10.1371/journal.pone.0065832] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/29/2013] [Indexed: 11/19/2022] Open
Abstract
Exported proteins of Streptococcus agalactiae (GBS), which include proteins localized to the bacterial surface or secreted into the extracellular environment, are key players for commensal and pathogenic interactions in the mammalian host. These proteins are transported across the cytoplasmic membrane via the general SecA secretory pathway and those containing the so-called LPXTG sorting motif are covalently attached to the peptidoglycan by sortase A. How SecA, sortase A, and LPXTG proteins are spatially distributed in GBS is not known. In the close relative Streptococcus pyogenes, it was shown that presence of the YSIRKG/S motif (literally YSIRKX3Gx2S) in the signal peptide (SP) constitutes the targeting information for secretion at the septum. Here, using conventional and deconvolution immunofluorescence analyses, we have studied in GBS strain NEM316 the localization of SecA, SrtA, and the secreted protein Bsp whose signal peptide contains a canonical YSIRKG/S motif (YSLRKykfGlaS). Replacing the SP of Bsp with four other SPs containing or not the YSIRKG/S motif did not alter the localized secretion of Bsp at the equatorial ring. Our results indicate that secretion and cell wall-anchoring machineries are localized at the division septum. Cell wall- anchored proteins displayed polar (PilB, Gbs0791), punctuate (CspA) or uniform distribution (Alp2) on the bacterial surface. De novo secretion of Gbs0791 following trypsin treatment indicates that it is secreted at the septum, then redistributed along the lateral sides, and finally accumulated to the poles. We conclude that the ±YSIRK SP rule driving compartimentalized secretion is not true in S. agalactiae.
Collapse
Affiliation(s)
- Sara Brega
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Elise Caliot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram positif, Paris, France
- CNRS, ERL 3526, Paris, France
- * E-mail:
| |
Collapse
|
48
|
Differential localization of the streptococcal accessory sec components and implications for substrate export. J Bacteriol 2012. [PMID: 23204472 DOI: 10.1128/jb.01742-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The accessory Sec system of Streptococcus gordonii is comprised of SecY2, SecA2, and five proteins (Asp1 through -5) that are required for the export of a serine-rich glycoprotein, GspB. We have previously shown that a number of the Asps interact with GspB, SecA2, or each other. To further define the roles of these Asps in export, we examined their subcellular localization in S. gordonii and in Escherichia coli expressing the streptococcal accessory Sec system. In particular, we assessed how the locations of these accessory Sec proteins were altered by the presence of other components. Using fluorescence microscopy, we found in E. coli that SecA2 localized within multiple foci at the cell membrane, regardless of whether other accessory Sec proteins were expressed. Asp2 alone localized to the cell poles but formed a similar punctate pattern at the membrane when SecA2 was present. Asp1 and Asp3 localized diffusely in the cytosol when expressed alone or with SecA2. However, these proteins redistributed to the membrane in a punctate arrangement when all of the accessory Sec components were present. Cell fractionation studies with S. gordonii further corroborated these microscopy results. Collectively, these findings indicate that Asp1 to -3 are not integral membrane proteins that form structural parts of the translocation channel. Instead, SecA2 serves as a docking site for Asp2, which in turn attracts a complex of Asp1 and Asp3 to the membrane. These protein interactions may be important for the trafficking of GspB to the cell membrane and its subsequent translocation.
Collapse
|
49
|
Bierne H, Dramsi S. Spatial positioning of cell wall-anchored virulence factors in Gram-positive bacteria. Curr Opin Microbiol 2012; 15:715-23. [PMID: 23141759 DOI: 10.1016/j.mib.2012.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 01/14/2023]
Abstract
Many virulence factors of Gram-positive bacteria are anchored to the peptidoglycan by a sorting signal. While surface display mechanisms are well characterized, less is known about the spatial and temporal organization of these proteins in the bacterial envelope. This review summarizes recent studies on the rod-shaped Listeria monocytogenes, ovococcal Streptococcus pyogenes and spherical Staphylococcus aureus bacteria that provide insights into the compartmentalization of the surface and distribution of peptidoglycan-anchored proteins in space and time. We discuss models that support mechanistic bases for localization of proteins at the poles, septum or lateral sites. The results indicate that deployment of virulence factors by pathogenic bacteria is a dynamic process tightly connected to secretion, cell morphogenesis, cell division rate and gene expression levels.
Collapse
Affiliation(s)
- Hélène Bierne
- Institut Pasteur, Unité des Interactions Bactéries Cellules, Paris, F-75015, France.
| | | |
Collapse
|
50
|
Cassone M, Gagne AL, Spruce LA, Seeholzer SH, Sebert ME. The HtrA protease from Streptococcus pneumoniae digests both denatured proteins and the competence-stimulating peptide. J Biol Chem 2012; 287:38449-59. [PMID: 23012372 DOI: 10.1074/jbc.m112.391482] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HtrA protease of Streptococcus pneumoniae functions both in a general stress response role and as an error sensor that specifically represses genetic competence when the overall level of biosynthetic errors in cellular proteins is low. However, the mechanism through which HtrA inhibits development of competence has been unknown. We found that HtrA digested the pneumococcal competence-stimulating peptide (CSP) and constituted the primary extracytoplasmic CSP-degrading activity in cultures of S. pneumoniae. Mass spectrometry demonstrated that cleavage predominantly followed residue Phe-8 of the CSP-1 isoform of the peptide within its central hydrophobic patch, and in competition assays, both CSP-1 and CSP-2 interacted with HtrA with similar efficiencies. More generally, analysis of β-casein digestion and of digestion within HtrA itself revealed a preference for substrates with non-polar residues at the P1 site. Consistent with a specificity for exposed hydrophobic residues, competition from native BSA only weakly inhibited digestion of CSP, but denaturation converted BSA into a strong competitive inhibitor of such proteolysis. Together these findings support a model in which digestion of CSP by HtrA is reduced in the presence of other unfolded proteins that serve as alternative targets for degradation. Such competition may provide a mechanism by which HtrA functions in a quality control capacity to monitor the frequency of biosynthetic errors that result in protein misfolding.
Collapse
Affiliation(s)
- Marco Cassone
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | |
Collapse
|