1
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Radler P, Loose M. A dynamic duo: Understanding the roles of FtsZ and FtsA for Escherichia coli cell division through in vitro approaches. Eur J Cell Biol 2024; 103:151380. [PMID: 38218128 DOI: 10.1016/j.ejcb.2023.151380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/15/2024] Open
Abstract
Bacteria divide by binary fission. The protein machine responsible for this process is the divisome, a transient assembly of more than 30 proteins in and on the surface of the cytoplasmic membrane. Together, they constrict the cell envelope and remodel the peptidoglycan layer to eventually split the cell into two. For Escherichia coli, most molecular players involved in this process have probably been identified, but obtaining the quantitative information needed for a mechanistic understanding can often not be achieved from experiments in vivo alone. Since the discovery of the Z-ring more than 30 years ago, in vitro reconstitution experiments have been crucial to shed light on molecular processes normally hidden in the complex environment of the living cell. In this review, we summarize how rebuilding the divisome from purified components - or at least parts of it - have been instrumental to obtain the detailed mechanistic understanding of the bacterial cell division machinery that we have today.
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Affiliation(s)
- Philipp Radler
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria; University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.
| | - Martin Loose
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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2
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Morrison JJ, Camberg JL. Building the Bacterial Divisome at the Septum. Subcell Biochem 2024; 104:49-71. [PMID: 38963483 DOI: 10.1007/978-3-031-58843-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Across living organisms, division is necessary for cell survival and passing heritable information to the next generation. For this reason, cell division is highly conserved among eukaryotes and prokaryotes. Among the most highly conserved cell division proteins in eukaryotes are tubulin and actin. Tubulin polymerizes to form microtubules, which assemble into cytoskeletal structures in eukaryotes, such as the mitotic spindle that pulls chromatids apart during mitosis. Actin polymerizes to form a morphological framework for the eukaryotic cell, or cytoskeleton, that undergoes reorganization during mitosis. In prokaryotes, two of the most highly conserved cell division proteins are the tubulin homolog FtsZ and the actin homolog FtsA. In this chapter, the functions of the essential bacterial cell division proteins FtsZ and FtsA and their roles in assembly of the divisome at the septum, the site of cell division, will be discussed. In most bacteria, including Escherichia coli, the tubulin homolog FtsZ polymerizes at midcell, and this step is crucial for recruitment of many other proteins to the division site. For this reason, both FtsZ abundance and polymerization are tightly regulated by a variety of proteins. The actin-like FtsA protein polymerizes and tethers FtsZ polymers to the cytoplasmic membrane. Additionally, FtsA interacts with later stage cell division proteins, which are essential for division and for building the new cell wall at the septum. Recent studies have investigated how actin-like polymerization of FtsA on the lipid membrane may impact division, and we will discuss this and other ways that division in bacteria is regulated through FtsZ and FtsA.
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Affiliation(s)
- Josiah J Morrison
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, USA
| | - Jodi L Camberg
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, USA.
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3
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Models versus pathogens: how conserved is the FtsZ in bacteria? Biosci Rep 2023; 43:232502. [PMID: 36695643 PMCID: PMC9939409 DOI: 10.1042/bsr20221664] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/10/2023] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
Combating anti-microbial resistance by developing alternative strategies is the need of the hour. Cell division, particularly FtsZ, is being extensively studied for its potential as an alternative target for anti-bacterial therapy. Bacillus subtilis and Escherichia coli are the two well-studied models for research on FtsZ, the leader protein of the cell division machinery. As representatives of gram-positive and gram-negative bacteria, respectively, these organisms have provided an extensive outlook into the process of cell division in rod-shaped bacteria. However, research on other shapes of bacteria, like cocci and ovococci, lags behind that of model rods. Even though most regions of FtsZ show sequence and structural conservation throughout bacteria, the differences in FtsZ functioning and interacting partners establish several different modes of division in different bacteria. In this review, we compare the features of FtsZ and cell division in the model rods B. subtilis and E. coli and the four pathogens: Staphylococcus aureus, Streptococcus pneumoniae, Mycobacterium tuberculosis, and Pseudomonas aeruginosa. Reviewing several recent articles on these pathogenic bacteria, we have highlighted the functioning of FtsZ, the unique roles of FtsZ-associated proteins, and the cell division processes in them. Further, we provide a detailed look at the anti-FtsZ compounds discovered and their target bacteria, emphasizing the need for elucidation of the anti-FtsZ mechanism of action in different bacteria. Current challenges and opportunities in the ongoing journey of identifying potent anti-FtsZ drugs have also been described.
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4
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Shinn MK, Cohan MC, Bullock JL, Ruff KM, Levin PA, Pappu RV. Connecting sequence features within the disordered C-terminal linker of Bacillus subtilis FtsZ to functions and bacterial cell division. Proc Natl Acad Sci U S A 2022; 119:e2211178119. [PMID: 36215496 PMCID: PMC9586301 DOI: 10.1073/pnas.2211178119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022] Open
Abstract
Intrinsically disordered regions (IDRs) can function as autoregulators of folded enzymes to which they are tethered. One example is the bacterial cell division protein FtsZ. This includes a folded core and a C-terminal tail (CTT) that encompasses a poorly conserved, disordered C-terminal linker (CTL) and a well-conserved 17-residue C-terminal peptide (CT17). Sites for GTPase activity of FtsZs are formed at the interface between GTP binding sites and T7 loops on cores of adjacent subunits within dimers. Here, we explore the basis of autoregulatory functions of the CTT in Bacillus subtilis FtsZ (Bs-FtsZ). Molecular simulations show that the CT17 of Bs-FtsZ makes statistically significant CTL-mediated contacts with the T7 loop. Statistical coupling analysis of more than 1,000 sequences from FtsZ orthologs reveals clear covariation of the T7 loop and the CT17 with most of the core domain, whereas the CTL is under independent selection. Despite this, we discover the conservation of nonrandom sequence patterns within CTLs across orthologs. To test how the nonrandom patterns of CTLs mediate CTT-core interactions and modulate FtsZ functionalities, we designed Bs-FtsZ variants by altering the patterning of oppositely charged residues within the CTL. Such alterations disrupt the core-CTT interactions, lead to anomalous assembly and inefficient GTP hydrolysis in vitro and protein degradation, aberrant assembly, and disruption of cell division in vivo. Our findings suggest that viable CTLs in FtsZs are likely to be IDRs that encompass nonrandom, functionally relevant sequence patterns that also preserve three-way covariation of the CT17, the T7 loop, and core domain.
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Affiliation(s)
- Min Kyung Shinn
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130
| | - Megan C. Cohan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
| | - Jessie L. Bullock
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | - Kiersten M. Ruff
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130
| | - Petra A. Levin
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130
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5
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Zhang C, Liu W, Deng J, Ma S, Chang Z, Yang J. Structural Insights into the Interaction between Bacillus subtilis SepF Assembly and FtsZ by Solid-State NMR Spectroscopy. J Phys Chem B 2022; 126:5219-5230. [PMID: 35799411 DOI: 10.1021/acs.jpcb.2c02810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In many species of Gram-positive bacteria, SepF participated in the membrane tethering of FtsZ Z-ring during bacteria division. However, atomic-level details of interaction between SepF and FtsZ in an assembled state are lacking. Here, by combining solid-state NMR (SSNMR) with biochemical analyses, the interaction of Bacillus subtilis SepF and the C-terminal domain (CTD) of FtsZ was investigated. We obtained near complete chemical shift assignments of SepF and determined the structural model of the SepF monomer. Interaction with FtsZ-CTD caused further packing of SepF rings, and SSNMR experiments revealed the affected residues locating at α1, α2, β3, and β4 of SepF. Solution NMR experiments of dimeric SepF constructed by point mutation strategy proved a prerequisite role of α-α interface formation in SepF for FtsZ binding. Overall, our results provide structural insights into the mechanisms of SepF-FtsZ interaction for better understanding the function of SepF in bacteria.
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Affiliation(s)
- Chang Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Wenjing Liu
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jing Deng
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Shaojie Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Ziwei Chang
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
| | - Jun Yang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.,National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China
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6
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Viola MG, Perdikari TM, Trebino CE, Rahmani N, Mathews KL, Pena CM, Chua XY, Xuan B, LaBreck CJ, Fawzi NL, Camberg JL. An enhancer sequence in the intrinsically disordered region of
FtsZ
promotes polymer‐guided substrate processing by
ClpXP
protease. Protein Sci 2022; 31:e4306. [PMID: 35481648 PMCID: PMC8996474 DOI: 10.1002/pro.4306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 11/09/2022]
Abstract
The essential bacterial division protein in Escherichia coli, FtsZ, assembles into the FtsZ-ring at midcell and recruits other proteins to the division site to promote septation. A region of the FtsZ amino acid sequence that links the conserved polymerization domain to a C-terminal protein interaction site was predicted to be intrinsically disordered and has been implicated in modulating spacing and architectural arrangements of FtsZ filaments. While the majority of cell division proteins that directly bind to FtsZ engage either the polymerization domain or the C-terminal interaction site, ClpX, the recognition and unfolding component of the bacterial ClpXP proteasome, has a secondary interaction with the predicted intrinsically disordered region (IDR) of FtsZ when FtsZ is polymerized. Here, we use NMR spectroscopy and reconstituted degradation reactions in vitro to demonstrate that this linker region is indeed disordered in solution and, further, that amino acids in the IDR of FtsZ enhance the degradation in polymer-guided interactions.
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Affiliation(s)
- Marissa G. Viola
- Department of Cell and Molecular Biology University of Rhode Island Kingston Rhode Island USA
| | | | - Catherine E. Trebino
- Department of Cell and Molecular Biology University of Rhode Island Kingston Rhode Island USA
| | - Negar Rahmani
- Department of Cell and Molecular Biology University of Rhode Island Kingston Rhode Island USA
| | - Kaylee L. Mathews
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program Brown University Providence Rhode Island USA
| | - Carolina Mejia Pena
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program Brown University Providence Rhode Island USA
| | - Xien Yu Chua
- Department of Molecular Pharmacology, Physiology & Biotechnology Brown University Providence Rhode Island USA
| | - Botai Xuan
- Department of Molecular Pharmacology, Physiology & Biotechnology Brown University Providence Rhode Island USA
| | - Christopher J. LaBreck
- Department of Cell and Molecular Biology University of Rhode Island Kingston Rhode Island USA
| | - Nicolas L. Fawzi
- Department of Molecular Pharmacology, Physiology & Biotechnology Brown University Providence Rhode Island USA
| | - Jodi L. Camberg
- Department of Cell and Molecular Biology University of Rhode Island Kingston Rhode Island USA
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7
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Levin PA, Janakiraman A. Localization, Assembly, and Activation of the Escherichia coli Cell Division Machinery. EcoSal Plus 2021; 9:eESP00222021. [PMID: 34910577 PMCID: PMC8919703 DOI: 10.1128/ecosalplus.esp-0022-2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 11/14/2021] [Indexed: 01/01/2023]
Abstract
Decades of research, much of it in Escherichia coli, have yielded a wealth of insight into bacterial cell division. Here, we provide an overview of the E. coli division machinery with an emphasis on recent findings. We begin with a short historical perspective into the discovery of FtsZ, the tubulin homolog that is essential for division in bacteria and archaea. We then discuss assembly of the divisome, an FtsZ-dependent multiprotein platform, at the midcell septal site. Not simply a scaffold, the dynamic properties of polymeric FtsZ ensure the efficient and uniform synthesis of septal peptidoglycan. Next, we describe the remodeling of the cell wall, invagination of the cell envelope, and disassembly of the division apparatus culminating in scission of the mother cell into two daughter cells. We conclude this review by highlighting some of the open questions in the cell division field, emphasizing that much remains to be discovered, even in an organism as extensively studied as E. coli.
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Affiliation(s)
- Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
- Center for Science & Engineering of Living Systems (CSELS), McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Anuradha Janakiraman
- Department of Biology, The City College of New York, New York, New York, USA
- Programs in Biology and Biochemistry, The Graduate Center of the City University of New York, New York, New York, USA
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8
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DiBiasio EC, Dickinson RA, Trebino CE, Ferreira CN, Morrison JJ, Camberg JL. The Stress-Active Cell Division Protein ZapE Alters FtsZ Filament Architecture to Facilitate Division in Escherichia coli. Front Microbiol 2021; 12:733085. [PMID: 34646253 PMCID: PMC8503651 DOI: 10.3389/fmicb.2021.733085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
During pathogenic infections, bacterial cells experience environmental stress conditions, including low oxygen and thermal stress. Bacterial cells proliferate during infection and divide by a mechanism characterized by the assembly of a large cytoskeletal structure at the division site called the Z-ring. The major protein constituting the Z-ring is FtsZ, a tubulin homolog and GTPase that utilizes the nucleotide to assemble into dynamic polymers. In Escherichia coli, many cell division proteins interact with FtsZ and modulate Z-ring assembly, while others direct cell wall insertion and peptidoglycan remodeling. Here, we show that ZapE, an ATPase that accumulates during late constriction, directly interacts with FtsZ and phospholipids in vitro. In the presence of adenosine triphosphate (ATP), ZapE induces bundling of GTP-induced FtsZ polymers; however, ZapE also binds FtsZ in the absence of GTP. The ZapE mutant protein ZapE(K84A), which is defective for ATP hydrolysis, also interacts with FtsZ and induces FtsZ filament bundling. In vivo, cultures of zapE deletion cells contain a low percentage of filamentous cells, suggesting that they have a modest division defect; however, they are able to grow when exposed to stress, such as high temperature and limited oxygen. When combined with the chromosomal deletion of minC, which encodes an FtsZ disassembly factor, ΔzapE ΔminC cells experience growth delays that slow proliferation at high temperature and prevent recovery. This synthetic slow growth phenotype after exposure to stress suggests that ZapE may function to ensure proliferation during and after stress, and this is exacerbated when cells are also deleted for minC. Expression of either ZapE or ZapE(K84A) complements the aberrant growth phenotypes in vivo suggesting that the division-associated role of ZapE does not require ZapE ATP hydrolysis. These results support that ZapE is a stress-regulated cell division protein that interacts directly with FtsZ and phospholipids, promoting growth and division after exposure to environmental stress.
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Affiliation(s)
- Eric C DiBiasio
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
| | - Rebecca A Dickinson
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
| | - Catherine E Trebino
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
| | - Colby N Ferreira
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
| | - Josiah J Morrison
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
| | - Jodi L Camberg
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI, United States
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9
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Reyes JS, Fuentes-Lemus E, Aspée A, Davies MJ, Monasterio O, López-Alarcón C. M. jannaschii FtsZ, a key protein in bacterial cell division, is inactivated by peroxyl radical-mediated methionine oxidation. Free Radic Biol Med 2021; 166:53-66. [PMID: 33588048 DOI: 10.1016/j.freeradbiomed.2021.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 11/17/2022]
Abstract
Oxidation and inactivation of FtsZ is of interest due to the key role of this protein in bacterial cell division. In the present work, we studied peroxyl radical (from AAPH, 2,2'-azobis(2-methylpropionamidine)dihydrochloride) mediated oxidation of the highly stable FtsZ protein (MjFtsZ) from M. jannaschii, a thermophilic microorganism. MjFtsZ contains eleven Met, and single Tyr and Trp residues which would be expected to be susceptible to oxidation. We hypothesized that exposure of MjFtsZ to AAPH-derived radicals would induce Met oxidation, and cross-linking (via di-Tyr and di-Trp formation), with concomitant loss of its functional polymerization and depolymerization (GTPase) activities. Solutions containing MjFtsZ and AAPH (10 or 100 mM) were incubated at 37 °C for 3 h. Polymerization/depolymerization were assessed by light scattering, while changes in mass were analyzed by SDS-PAGE. Amino acid consumption was quantified by HPLC with fluorescence detection, or direct fluorescence (Trp). Oxidation products and modifications at individual Met residues were quantified by UPLC with mass detection. Oxidation inhibited polymerization-depolymerization activity, and yielded low levels of irreversible protein dimers. With 10 mM AAPH only Trp and Met were consumed giving di-alcohols, kynurenine and di-Trp (from Trp) and the sulfoxide (from Met). With 100 mM AAPH low levels of Tyr oxidation (but not di-Tyr formation) were also observed. Correlation with the functional analyses indicates that Met oxidation, and particularly Met164 is the key driver of MjFtsZ inactivation, probably as a result of the position of this residue at the protein-protein interface of longitudinal interactions and in close proximity to the GTP binding site.
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Affiliation(s)
- Juan Sebastián Reyes
- Departamento de Química Física, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Chile; Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Chile
| | - Eduardo Fuentes-Lemus
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Alexis Aspée
- Departamento de Ciencias Del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Chile
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Octavio Monasterio
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Chile.
| | - Camilo López-Alarcón
- Departamento de Química Física, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Chile.
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10
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Molecular Characterization of the Burkholderia cenocepacia dcw Operon and FtsZ Interactors as New Targets for Novel Antimicrobial Design. Antibiotics (Basel) 2020; 9:antibiotics9120841. [PMID: 33255486 PMCID: PMC7761207 DOI: 10.3390/antibiotics9120841] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 12/20/2022] Open
Abstract
The worldwide spread of antimicrobial resistance highlights the need of new druggable cellular targets. The increasing knowledge of bacterial cell division suggested the potentiality of this pathway as a pool of alternative drug targets, mainly based on the essentiality of these proteins, as well as on the divergence from their eukaryotic counterparts. People suffering from cystic fibrosis are particularly challenged by the lack of antibiotic alternatives. Among the opportunistic pathogens that colonize the lungs of these patients, Burkholderia cenocepacia is a well-known multi-drug resistant bacterium, particularly difficult to treat. Here we describe the organization of its division cell wall (dcw) cluster: we found that 15 genes of the dcw operon can be transcribed as a polycistronic mRNA from mraZ to ftsZ and that its transcription is under the control of a strong promoter regulated by MraZ. B. cenocepacia J2315 FtsZ was also shown to interact with the other components of the divisome machinery, with a few differences respect to other bacteria, such as the direct interaction with FtsQ. Using an in vitro sedimentation assay, we validated the role of SulA as FtsZ inhibitor, and the roles of FtsA and ZipA as tethers of FtsZ polymers. Together our results pave the way for future antimicrobial design based on the divisome as pool of antibiotic cellular targets.
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11
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Nordyke CT, Ahmed YM, Puterbaugh RZ, Bowman GR, Varga K. Intrinsically Disordered Bacterial Polar Organizing Protein Z, PopZ, Interacts with Protein Binding Partners Through an N-terminal Molecular Recognition Feature. J Mol Biol 2020; 432:6092-6107. [PMID: 33058876 DOI: 10.1016/j.jmb.2020.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/18/2020] [Accepted: 09/25/2020] [Indexed: 11/15/2022]
Abstract
The polar organizing protein Z (PopZ) is necessary for the formation of three-dimensional microdomains at the cell poles in Caulobacter crescentus, where it functions as a hub protein that recruits multiple regulatory proteins from the cytoplasm. Although a large portion of the protein is predicted to be natively unstructured, in reconstituted systems PopZ can self-assemble into a macromolecular scaffold that directly binds to at least ten different proteins. Here we report the solution NMR structure of PopZΔ134-177, a truncated form of PopZ that does not self-assemble but retains the ability to interact with heterologous proteins. We show that the unbound form of PopZΔ134-177 is unstructured in solution, with the exception of a small amphipathic α-helix in residues M10-I17, which is included within a highly conserved region near the N-terminal. In applying NMR techniques to map the interactions between PopZΔ134-177 and one of its binding partners, RcdA, we find evidence that the α-helix and adjoining amino acids extending to position E23 serve as the core of the binding motif. Consistent with this, a point mutation at position I17 severely compromises binding. Our results show that a partially structured Molecular Recognition Feature (MoRF) within an intrinsically disordered domain of PopZ contributes to the assembly of polar microdomains, revealing a structural basis for complex network assembly in Alphaproteobacteria that is analogous to those formed by intrinsically disordered hub proteins in other kingdoms.
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Affiliation(s)
- Christopher T Nordyke
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, United States
| | - Yasin M Ahmed
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, United States
| | - Ryan Z Puterbaugh
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, United States
| | - Grant R Bowman
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, United States.
| | - Krisztina Varga
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, United States.
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12
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Swain A, Anil Kumar AV. A stochastic model for dynamics of FtsZ filaments and the formation of Z -ring. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:43. [PMID: 32617695 DOI: 10.1140/epje/i2020-11967-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Understanding the mechanisms responsible for the formation and growth of FtsZ polymers and their subsequent formation of the Z -ring is important for gaining insight into the cell division in prokaryotic cells. In this work, we present a minimal stochastic model that qualitatively reproduces in vitro observations of polymerization, formation of dynamic contractile ring that is stable for a long time and depolymerization shown by FtsZ polymer filaments. In this stochastic model, we explore different mechanisms for ring breaking and hydrolysis. In addition to hydrolysis, which is known to regulate the dynamics of other tubulin polymers like microtubules, we find that the presence of the ring allows for an additional mechanism for regulating the dynamics of FtsZ polymers. Ring breaking dynamics in the presence of hydrolysis naturally induce rescue and catastrophe events in this model irrespective of the mechanism of hydrolysis.
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Affiliation(s)
- Arabind Swain
- School of Physical Sciences, National Institute of Science Education and Research, 752050, Jatni, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, 400094, Mumbai, India
| | - A V Anil Kumar
- School of Physical Sciences, National Institute of Science Education and Research, 752050, Jatni, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, 400094, Mumbai, India
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13
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Silber N, Matos de Opitz CL, Mayer C, Sass P. Cell division protein FtsZ: from structure and mechanism to antibiotic target. Future Microbiol 2020; 15:801-831. [DOI: 10.2217/fmb-2019-0348] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Antimicrobial resistance to virtually all clinically applied antibiotic classes severely limits the available options to treat bacterial infections. Hence, there is an urgent need to develop and evaluate new antibiotics and targets with resistance-breaking properties. Bacterial cell division has emerged as a new antibiotic target pathway to counteract multidrug-resistant pathogens. New approaches in antibiotic discovery and bacterial cell biology helped to identify compounds that either directly interact with the major cell division protein FtsZ, thereby perturbing the function and dynamics of the cell division machinery, or affect the structural integrity of FtsZ by inducing its degradation. The impressive antimicrobial activities and resistance-breaking properties of certain compounds validate the inhibition of bacterial cell division as a promising strategy for antibiotic intervention.
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Affiliation(s)
- Nadine Silber
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Cruz L Matos de Opitz
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Christian Mayer
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Peter Sass
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology & Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, Tübingen 72076, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen 72076, Germany
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14
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Essential dynamic interdependence of FtsZ and SepF for Z-ring and septum formation in Corynebacterium glutamicum. Nat Commun 2020; 11:1641. [PMID: 32242019 PMCID: PMC7118173 DOI: 10.1038/s41467-020-15490-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 03/09/2020] [Indexed: 12/25/2022] Open
Abstract
The mechanisms of Z-ring assembly and regulation in bacteria are poorly understood, particularly in non-model organisms. Actinobacteria, a large bacterial phylum that includes the pathogen Mycobacterium tuberculosis, lack the canonical FtsZ-membrane anchors and Z-ring regulators described for E. coli. Here we investigate the physiological function of Corynebacterium glutamicum SepF, the only cell division-associated protein from Actinobacteria known to interact with the conserved C-terminal tail of FtsZ. We show an essential interdependence of FtsZ and SepF for formation of a functional Z-ring in C. glutamicum. The crystal structure of the SepF–FtsZ complex reveals a hydrophobic FtsZ-binding pocket, which defines the SepF homodimer as the functional unit, and suggests a reversible oligomerization interface. FtsZ filaments and lipid membranes have opposing effects on SepF polymerization, indicating that SepF has multiple roles at the cell division site, involving FtsZ bundling, Z-ring tethering and membrane reshaping activities that are needed for proper Z-ring assembly and function. The mechanisms of Z-ring assembly and regulation in bacteria are poorly understood, particularly in non-model organisms. Here, Sogues et al. study the interaction between FtsZ and SepF in Corynebacterium glutamicum, showing an essential interdependence of these proteins for formation of a functional Z-ring.
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15
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Mir MA, Srinivasan R, Ajitkumar P. MtFtsX a predicted membrane domain of ABC transporter complex MtFtsEX of Mycobacterium tuberculosis interacts with the cell division protein MtFtsZ. Int J Mycobacteriol 2019; 8:281-286. [PMID: 31512605 DOI: 10.4103/ijmy.ijmy_98_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Bacterial cytokinesis is orchestrated by a complex of dozen of proteins called 'divisome' at the mid-cell site. FtsZ, the eukaryotic tubulin homolog, localizes to the mid-cell site where it polymerizes and forms a cytokinetic Z-ring. The Z-ring acts as a docking platform for other proteins to localize. In model organisms, Escherichia coli and Bacillus subtilis, FtsZ is known to interact with several proteins. The role of few of these interactions is known, while of others is yet to be studied. In Mycobacterium tuberculosis, the cell division and its regulation are poorly studied. Although, most of the divisome proteins are conserved in M. tuberculosis, surprisingly the homologues of the protein factors required for membrane association of Z-ring and its stabilization are absent. In E. coli FtsE and FtsX, the constituent ATPase and membrane domains of the ABC transporter complex, localize to the Z-ring immediately after Z-ring stabilizing proteins, ZipA and FtsA. Therefore, investigation of the interaction between MtFtsX and MtFtsZ is demanding. Methods Bacterial two-hybrid system was used to identify the interaction between MtFtsE and MtFtsZ. This interaction was further confirmed by biochemical methods of Ni2+-NTA agarose pull-down and coimmunoprecipitation. Results and Conclusion Here, we demonstrated that MtFtsX interacts with MtFtsZ in vivo and ex-vivo. Further, we showed that self-interacting MtFtsX interacts with MtFtsE. However, we did not find any interaction between MtFtsE and MtFtsZ. These results suggest that the membrane domain MtFtsX of the ABC transporter complex 'MtFtsEX' might be the membrane-tethering and stabilizing factor for Z-ring in M. tuberculosis.
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Affiliation(s)
- Mushtaq Ahmad Mir
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Asir, Saudi Arabia
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, Odisha, India
| | - Parthasarathi Ajitkumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
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16
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Wang M, Fang C, Ma B, Luo X, Hou Z. Regulation of cytokinesis: FtsZ and its accessory proteins. Curr Genet 2019; 66:43-49. [PMID: 31209564 DOI: 10.1007/s00294-019-01005-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/08/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022]
Abstract
Bacterial cell division is a highly controlled process regulated accurately by a diverse array of proteins spatially and temporally working together. Among these proteins, FtsZ is recognized as a cytoskeleton protein because it can assemble into a ring-like structure called Z-ring at midcell. Z-ring recruits downstream proteins, thus forming a multiprotein complex termed the divisome. When the Z-ring scaffold is established and the divisome matures, peptidoglycan (PG) biosynthesis and chromosome segregation are triggered. In this review, we focus on multiple interactions between FtsZ and its accessory proteins in bacterial cell cytokinesis, including FtsZ localization, Z-ring formation and stabilization, PG biosynthesis, and chromosome segregation. Understanding the interactions among these proteins may help discover superior targets on treating bacterial infectious diseases.
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Affiliation(s)
- Mingzhi Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Chao Fang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Bo Ma
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China
| | - Zheng Hou
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, China.
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17
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At the Heart of Bacterial Cytokinesis: The Z Ring. Trends Microbiol 2019; 27:781-791. [PMID: 31171437 DOI: 10.1016/j.tim.2019.04.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/22/2019] [Accepted: 04/29/2019] [Indexed: 11/20/2022]
Abstract
Bacterial cell division is mediated by the divisome which is organized by the Z ring, a cytoskeletal element formed by the polymerization of the tubulin homologue FtsZ. Despite billions of years of bacterial evolution, the Z ring is nearly universal among bacteria that have a cell wall and divide by binary fission. Recent studies have revealed the mechanism of cooperative assembly of FtsZ and that the Z ring consists of patches of FtsZ filaments tethered to the membrane that treadmill to distribute the septal biosynthetic machinery. Here, we summarize these advances and discuss questions raised by these new findings.
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18
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MinC N- and C-Domain Interactions Modulate FtsZ Assembly, Division Site Selection, and MinD-Dependent Oscillation in Escherichia coli. J Bacteriol 2019; 201:JB.00374-18. [PMID: 30455283 DOI: 10.1128/jb.00374-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/15/2018] [Indexed: 11/20/2022] Open
Abstract
The Min system in Escherichia coli, consisting of MinC, MinD, and MinE proteins, regulates division site selection by preventing assembly of the FtsZ-ring (Z-ring) and exhibits polar oscillation in vivo MinC antagonizes FtsZ polymerization, and in vivo, the cellular location of MinC is controlled by a direct association with MinD at the membrane. To further understand the interactions of MinC with FtsZ and MinD, we performed a mutagenesis screen to identify substitutions in minC that are associated with defects in cell division. We identified amino acids in both the N- and C-domains of MinC that are important for direct interactions with FtsZ and MinD in vitro, as well as mutations that modify the observed in vivo oscillation of green fluorescent protein (GFP)-MinC. Our results indicate that there are two distinct surface-exposed sites on MinC that are important for direct interactions with FtsZ, one at a cleft on the surface of the N-domain and a second on the C-domain that is adjacent to the MinD interaction site. Mutation of either of these sites leads to slower oscillation of GFP-MinC in vivo, although the MinC mutant proteins are still capable of a direct interaction with MinD in phospholipid recruitment assays. Furthermore, we demonstrate that interactions between FtsZ and both sites of MinC identified here are important for assembly of FtsZ-MinC-MinD complexes and that the conserved C-terminal end of FtsZ is not required for MinC-MinD complex formation with GTP-dependent FtsZ polymers.IMPORTANCE Bacterial cell division proceeds through the coordinated assembly of the FtsZ-ring, or Z-ring, at the site of division. Assembly of the Z-ring requires polymerization of FtsZ, which is regulated by several proteins in the cell. In Escherichia coli, the Min system, which contains MinC, MinD, and MinE proteins, exhibits polar oscillation and inhibits the assembly of FtsZ at nonseptal locations. Here, we identify regions on the surface of MinC that are important for contacting FtsZ and destabilizing FtsZ polymers.
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19
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Guo H, Huang C, Jiang L, Cheng T, Feng T, Xia Q. Transcriptome analysis of the response of silkworm to drastic changes in ambient temperature. Appl Microbiol Biotechnol 2018; 102:10161-10170. [DOI: 10.1007/s00253-018-9387-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 09/06/2018] [Indexed: 12/11/2022]
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20
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Roseboom W, Nazir MG, Meiresonne NY, Mohammadi T, Verheul J, Buncherd H, Bonvin AMJJ, de Koning LJ, de Koster CG, de Jong L, den Blaauwen T. Mapping the Contact Sites of the Escherichia coli Division-Initiating Proteins FtsZ and ZapA by BAMG Cross-Linking and Site-Directed Mutagenesis. Int J Mol Sci 2018; 19:ijms19102928. [PMID: 30261644 PMCID: PMC6213154 DOI: 10.3390/ijms19102928] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 09/13/2018] [Accepted: 09/19/2018] [Indexed: 12/21/2022] Open
Abstract
Cell division in bacteria is initiated by the polymerization of FtsZ at midcell in a ring-like structure called the Z-ring. ZapA and other proteins assist Z-ring formation and ZapA binds ZapB, which senses the presence of the nucleoids. The FtsZ–ZapA binding interface was analyzed by chemical cross-linking mass spectrometry (CXMS) under in vitro FtsZ-polymerizing conditions in the presence of GTP. Amino acids residue K42 from ZapA was cross-linked to amino acid residues K51 and K66 from FtsZ, close to the interphase between FtsZ molecules in protofilaments. Five different cross-links confirmed the tetrameric structure of ZapA. A number of FtsZ cross-links suggests that its C-terminal domain of 55 residues, thought to be largely disordered, has a limited freedom to move in space. Site-directed mutagenesis of ZapA reveals an interaction site in the globular head of the protein close to K42. Using the information on the cross-links and the mutants that lost the ability to interact with FtsZ, a model of the FtsZ protofilament–ZapA tetramer complex was obtained by information-driven docking with the HADDOCK2.2 webserver.
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Affiliation(s)
- Winfried Roseboom
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Madhvi G Nazir
- Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Nils Y Meiresonne
- Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Tamimount Mohammadi
- Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Jolanda Verheul
- Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Hansuk Buncherd
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
- Faculty of Medical Technology, Prince of Songkla University, Songkhla 90110, Thailand.
| | - Alexandre M J J Bonvin
- Computational Structural Biology, Faculty of Science-Chemistry, University of Utrecht, Padualaan 83584CH Utrecht, The Netherlands.
| | - Leo J de Koning
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Chris G de Koster
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Luitzen de Jong
- Mass Spectrometry of Biomacromolecules, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Tanneke den Blaauwen
- Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
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21
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Sundararajan K, Goley ED. The intrinsically disordered C-terminal linker of FtsZ regulates protofilament dynamics and superstructure in vitro. J Biol Chem 2017; 292:20509-20527. [PMID: 29089389 DOI: 10.1074/jbc.m117.809939] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/17/2017] [Indexed: 11/06/2022] Open
Abstract
The bacterial tubulin FtsZ polymerizes to form a discontinuous ring that drives bacterial cell division by directing local cell wall synthesis. FtsZ comprises a polymerizing GTPase domain, an intrinsically disordered C-terminal linker (CTL), and a C-terminal conserved peptide (CTC). FtsZ protofilaments align circumferentially in the cell, with the CTC mediating attachment to membrane-associated division proteins. The assembly of FtsZ protofilaments into dynamic clusters is critical for cell division, but the interactions between protofilaments and regulatory mechanisms that mediate cluster assembly and dynamics are unknown. Here, we describe a role for the CTL of Caulobacter crescentus FtsZ as an intrinsic regulator of lateral interactions between protofilaments in vitro FtsZ lacking its CTL (ΔCTL) shows a dramatically increased propensity to form long multifilament bundles compared with wild type (WT). ΔCTL also displays a reduced GTP hydrolysis rate compared with WT, but this altered activity does not account for bundle formation, as reducing protofilament turnover in WT is not sufficient to induce bundling. Surprisingly, binding of the membrane-anchoring protein FzlC disrupts ΔCTL bundling in a CTC-dependent manner. Moreover, the CTL affects the ability of the FtsZ curving protein FzlA to promote formation of helical bundles. We conclude that the CTL of FtsZ influences polymer structure and dynamics both through intrinsic effects on lateral interactions and turnover and by influencing extrinsic regulation of FtsZ by binding partners. Our characterization of CTL function provides a biochemical handle for understanding the relationship between FtsZ-ring structure and function in bacterial cytokinesis.
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Affiliation(s)
- Kousik Sundararajan
- From the Department of Biological Chemistry, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | - Erin D Goley
- From the Department of Biological Chemistry, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205
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22
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CbtA toxin of Escherichia coli inhibits cell division and cell elongation via direct and independent interactions with FtsZ and MreB. PLoS Genet 2017; 13:e1007007. [PMID: 28931012 PMCID: PMC5624674 DOI: 10.1371/journal.pgen.1007007] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/02/2017] [Accepted: 09/06/2017] [Indexed: 12/12/2022] Open
Abstract
The toxin components of toxin-antitoxin modules, found in bacterial plasmids, phages, and chromosomes, typically target a single macromolecule to interfere with an essential cellular process. An apparent exception is the chromosomally encoded toxin component of the E. coli CbtA/CbeA toxin-antitoxin module, which can inhibit both cell division and cell elongation. A small protein of only 124 amino acids, CbtA, was previously proposed to interact with both FtsZ, a tubulin homolog that is essential for cell division, and MreB, an actin homolog that is essential for cell elongation. However, whether or not the toxic effects of CbtA are due to direct interactions with these predicted targets is not known. Here, we genetically separate the effects of CbtA on cell elongation and cell division, showing that CbtA interacts directly and independently with FtsZ and MreB. Using complementary genetic approaches, we identify the functionally relevant target surfaces on FtsZ and MreB, revealing that in both cases, CbtA binds to surfaces involved in essential cytoskeletal filament architecture. We show further that each interaction contributes independently to CbtA-mediated toxicity and that disruption of both interactions is required to alleviate the observed toxicity. Although several other protein modulators are known to target FtsZ, the CbtA-interacting surface we identify represents a novel inhibitory target. Our findings establish CbtA as a dual function toxin that inhibits both cell division and cell elongation via direct and independent interactions with FtsZ and MreB. Bacterially encoded toxin-antitoxin systems, which consist of a small toxin protein that is co-produced with a neutralizing antitoxin, are a potential avenue for the identification of novel antibiotic targets. These toxins typically target essential cellular processes, causing growth arrest or cell death when unchecked by the antitoxin. Our study is focused on the CbtA toxin of E. coli, which was known to inhibit both bacterial cell division and also bacterial cell elongation (the process by which rod-shaped bacteria grow prior to cell division). We report that the effects of CbtA on cell division and cell elongation are genetically separable, and that they are due to direct and independent interactions with its targets FtsZ and MreB, essential cytoskeletal proteins that direct cell division and cell elongation, respectively. Our genetic analysis defines the functionally relevant target surfaces on FtsZ and MreB; in the case of FtsZ this surface represents a novel inhibitory target. As a dual-function toxin that independently targets two essential cytoskeletal elements, CbtA could guide the design of dual-function antibiotics whose ability to independently target more than one essential cellular process might impede the development of drug resistance, which is a growing public health threat.
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