1
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De Tito S, Turacchio G, Valente C. Negative Staining Electron Microscopy for Morpho-Functional Characterization of Purified Golgi Membranes from Mammalian Cells. Methods Mol Biol 2022; 2557:225-234. [PMID: 36512218 DOI: 10.1007/978-1-0716-2639-9_14] [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: 12/15/2022]
Abstract
The Golgi apparatus is a highly dynamic organelle that controls lipid and protein sorting in the endocytic and exocytic cellular pathways. Perturbation of the lipid homeostasis or of the molecular machineries that regulate membrane remodeling/trafficking events on the Golgi membranes can dramatically change the morphology and functions of the Golgi apparatus. So far, several approaches have been described to characterize and define the Golgi morphology in intact cells and in vitro. Here, we describe the application of negative staining (NS) electron microscopy (EM) on purified Golgi membranes from HeLa cells. This approach allows to quantify and functionally characterize membrane remodeling events upon specific treatments that alter the Golgi morphology.
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Affiliation(s)
- Stefano De Tito
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy.,Molecular Cell Biology of Autophagy, The Francis Crick Institute, London, UK
| | - Gabriele Turacchio
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy.
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2
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Vélez M. How Does the Spatial Confinement of FtsZ to a Membrane Surface Affect Its Polymerization Properties and Function? Front Microbiol 2022; 13:757711. [PMID: 35592002 PMCID: PMC9111741 DOI: 10.3389/fmicb.2022.757711] [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: 08/12/2021] [Accepted: 01/27/2022] [Indexed: 11/15/2022] Open
Abstract
FtsZ is the cytoskeletal protein that organizes the formation of the septal ring and orchestrates bacterial cell division. Its association to the membrane is essential for its function. In this mini-review I will address the question of how this association can interfere with the structure and dynamic properties of the filaments and argue that its dynamics could also remodel the underlying lipid membrane through its activity. Thus, lipid rearrangement might need to be considered when trying to understand FtsZ’s function. This new element could help understand how FtsZ assembly coordinates positioning and recruitment of the proteins forming the septal ring inside the cell with the activity of the machinery involved in peptidoglycan synthesis located in the periplasmic space.
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Affiliation(s)
- Marisela Vélez
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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3
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Song D, Zhang N, Ma Y, Zhang S, Chen W, Guo T, Ma S. Acridinium-conjugated aromatic heterocycles as highly potent FtsZ inhibitors: Design, synthesis, and biological evaluation. Arch Pharm (Weinheim) 2022; 355:e2100400. [PMID: 35267210 DOI: 10.1002/ardp.202100400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 11/05/2022]
Abstract
The epidemic of multidrug resistance (MDR) is a serious threat to public health, and new classes of antibiotics with novel mechanisms of action are in critical need. We rationally designed and efficiently synthesized three series of new chemical entities with potential antibacterial activity targeting filamenting temperature-sensitive mutant Z (FtsZ). Evaluation of these compounds against a panel of Gram-positive bacteria including MDR and vancomycin-resistant Enterococcus strains indicated that most compounds showed enhanced antibacterial efficacy, comparable or even superior to the reference drugs. The newly synthesized compounds proved to be substrates of the Escherichia coli efflux pump AcrB, thus affecting the activity. Their structure-activity relationships were summarized in detail. The most potent compound 10f quickly eliminated bacteria in a bactericidal mode, with low susceptibility to induce bacterial resistance. Further mechanistic studies with the BsFtsZ protein revealed that 10f functioned as an effective FtsZ inhibitor through altering the dynamics of FtsZ self-polymerization via a stimulatory mechanism, which leads to inhibition of cell division and cell death. Besides, 10f not only displayed no obvious cytotoxicity to mammalian cells but also had a high efficacy in a murine model of bacteremia in vivo. Regarded as a whole, our findings highlight 10f as a promising new FtsZ-targeting bactericidal agent.
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Affiliation(s)
- Di Song
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Nan Zhang
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Yangchun Ma
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Shenyan Zhang
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Weijin Chen
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Ting Guo
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Shutao Ma
- Key Laboratory of Chemical Biology (Ministry of Education), Department of Medicinal Chemistry, School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
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4
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Guo L, Yang L, Qi Y, Niyazi G, Huang L, Gou L, Wang Z, Zhang L, Liu D, Wang X, Chen H, Kong MG. Cold Atmospheric-Pressure Plasma Caused Protein Damage in Methicillin-Resistant Staphylococcus aureus Cells in Biofilms. Microorganisms 2021; 9:microorganisms9051072. [PMID: 34067642 PMCID: PMC8156483 DOI: 10.3390/microorganisms9051072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 01/16/2023] Open
Abstract
Biofilms formed by multidrug-resistant bacteria are a major cause of hospital-acquired infections. Cold atmospheric-pressure plasma (CAP) is attractive for sterilization, especially to disrupt biofilms formed by multidrug-resistant bacteria. However, the underlying molecular mechanism is not clear. In this study, CAP effectively reduced the living cells in the biofilms formed by methicillin-resistant Staphylococcus aureus, and 6 min treatment with CAP reduced the S. aureus cells in biofilms by 3.5 log10. The treatment with CAP caused the polymerization of SaFtsZ and SaClpP proteins in the S. aureus cells of the biofilms. In vitro analysis demonstrated that recombinant SaFtsZ lost its self-assembly capability, and recombinant SaClpP lost its peptidase activity after 2 min of treatment with CAP. Mass spectrometry showed oxidative modifications of a cluster of peaks differing by 16 Da, 31 Da, 32 Da, 47 Da, 48 Da, 62 Da, and 78 Da, induced by reactive species of CAP. It is speculated that the oxidative damage to proteins in S. aureus cells was induced by CAP, which contributed to the reduction of biofilms. This study elucidates the biological effect of CAP on the proteins in bacterial cells of biofilms and provides a basis for the application of CAP in the disinfection of biofilms.
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Affiliation(s)
- Li Guo
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
- Correspondence: (L.G.); (D.L.)
| | - Lu Yang
- School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (L.Y.); (G.N.)
| | - Yu Qi
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
| | - Gulimire Niyazi
- School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China; (L.Y.); (G.N.)
| | - Lingling Huang
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
| | - Lu Gou
- School of Physics, Xi’an Jiaotong University, Xi’an 710049, China; (L.G.); (L.Z.)
| | - Zifeng Wang
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
| | - Lei Zhang
- School of Physics, Xi’an Jiaotong University, Xi’an 710049, China; (L.G.); (L.Z.)
| | - Dingxin Liu
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
- Correspondence: (L.G.); (D.L.)
| | - Xiaohua Wang
- State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi’an Jiaotong University, Xi’an 710049, China; (Y.Q.); (L.H.); (Z.W.); (X.W.)
| | - Hailan Chen
- Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (H.C.); (M.G.K.)
| | - Michael G. Kong
- Frank Reidy Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (H.C.); (M.G.K.)
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA
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5
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Zorrilla S, Monterroso B, Robles-Ramos MÁ, Margolin W, Rivas G. FtsZ Interactions and Biomolecular Condensates as Potential Targets for New Antibiotics. Antibiotics (Basel) 2021; 10:antibiotics10030254. [PMID: 33806332 PMCID: PMC7999717 DOI: 10.3390/antibiotics10030254] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 12/18/2022] Open
Abstract
FtsZ is an essential and central protein for cell division in most bacteria. Because of its ability to organize into dynamic polymers at the cell membrane and recruit other protein partners to form a “divisome”, FtsZ is a leading target in the quest for new antibacterial compounds. Strategies to potentially arrest the essential and tightly regulated cell division process include perturbing FtsZ’s ability to interact with itself and other divisome proteins. Here, we discuss the available methodologies to screen for and characterize those interactions. In addition to assays that measure protein-ligand interactions in solution, we also discuss the use of minimal membrane systems and cell-like compartments to better approximate the native bacterial cell environment and hence provide a more accurate assessment of a candidate compound’s potential in vivo effect. We particularly focus on ways to measure and inhibit under-explored interactions between FtsZ and partner proteins. Finally, we discuss recent evidence that FtsZ forms biomolecular condensates in vitro, and the potential implications of these assemblies in bacterial resistance to antibiotic treatment.
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Affiliation(s)
- Silvia Zorrilla
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (M.-Á.R.-R.); (G.R.)
- Correspondence: (S.Z.); (B.M.); Tel.: +34-91-837-3112 (S.Z. & B.M.)
| | - Begoña Monterroso
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (M.-Á.R.-R.); (G.R.)
- Correspondence: (S.Z.); (B.M.); Tel.: +34-91-837-3112 (S.Z. & B.M.)
| | - Miguel-Ángel Robles-Ramos
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (M.-Á.R.-R.); (G.R.)
| | - William Margolin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas, Houston, TX 77030, USA;
| | - Germán Rivas
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), 28040 Madrid, Spain; (M.-Á.R.-R.); (G.R.)
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6
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FtsZ inhibitors as a new genera of antibacterial agents. Bioorg Chem 2019; 91:103169. [PMID: 31398602 DOI: 10.1016/j.bioorg.2019.103169] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 07/28/2019] [Accepted: 07/29/2019] [Indexed: 11/21/2022]
Abstract
The continuous emergence and rapid spread of a multidrug-resistant strain of bacterial pathogens have demanded the discovery and development of new antibacterial agents. A highly conserved prokaryotic cell division protein FtsZ is considered as a promising target by inhibiting bacterial cytokinesis. Inhibition of FtsZ assembly restrains the cell-division complex known as divisome, which results in filamentation, leading to lysis of the cell. This review focuses on details relating to the structure, function, and influence of FtsZ in bacterial cytokinesis. It also summarizes on the recent perspective of the known natural and synthetic inhibitors directly acting on FtsZ protein, with prominent antibacterial activities. A series of benzamides, trisubstituted benzimidazoles, isoquinolene, guanine nucleotides, zantrins, carbonylpyridine, 4 and 5-Substituted 1-phenyl naphthalenes, sulindac, vanillin analogues were studied here and recognized as FtsZ inhibitors that act either by disturbing FtsZ polymerization and/or GTPase activity. Doxorubicin, from a U.S. FDA, approved drug library displayed strong interaction with FtsZ. Several of the molecules discussed, include the prodrugs of benzamide based compound PC190723 (TXA-709 and TXA707). These molecules have exhibited the most prominent antibacterial activity against several strains of Staphylococcus aureus with minimal toxicity and good pharmacokinetics properties. The evidence of research reports and patent documentations on FtsZ protein has disclosed distinct support in the field of antibacterial drug discovery. The pressing need and interest shall facilitate the discovery of novel clinical molecules targeting FtsZ in the upcoming days.
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7
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Surface Orientation and Binding Strength Modulate Shape of FtsZ on Lipid Surfaces. Int J Mol Sci 2019; 20:ijms20102545. [PMID: 31137602 PMCID: PMC6566678 DOI: 10.3390/ijms20102545] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/15/2019] [Accepted: 05/23/2019] [Indexed: 01/16/2023] Open
Abstract
We have used a simple model system to test the prediction that surface attachment strength of filaments presenting a torsion would affect their shape and properties. FtsZ from E. coli containing one cysteine in position 2 was covalently attached to a lipid bilayer containing maleimide lipids either in their head group (to simulate tight attachment) or at the end of a polyethylene glycol molecule attached to the head group (to simulate loose binding). We found that filaments tightly attached grew straight, growing from both ends, until they formed a two-dimensional lattice. Further monomer additions to their sides generated a dense layer of oriented filaments that fully covered the lipid membrane. After this point the surface became unstable and the bilayer detached from the surface. Filaments with a loose binding were initially curved and later evolved into straight thicker bundles that destabilized the membrane after reaching a certain surface density. Previously described theoretical models of FtsZ filament assembly on surfaces that include lateral interactions, spontaneous curvature, torsion, anchoring to the membrane, relative geometry of the surface and the filament ‘living-polymer’ condition in the presence of guanosine triphosphate (GTP) can offer some clues about the driving forces inducing these filament rearrangements.
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8
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Mateos-Gil P, Tarazona P, Vélez M. Bacterial cell division: modeling FtsZ assembly and force generation from single filament experimental data. FEMS Microbiol Rev 2019; 43:73-87. [PMID: 30376053 DOI: 10.1093/femsre/fuy039] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/26/2018] [Indexed: 12/24/2022] Open
Abstract
The bacterial cytoskeletal protein FtsZ binds and hydrolyzes GTP, self-aggregates into dynamic filaments and guides the assembly of the septal ring on the inner side of the membrane at midcell. This ring constricts the cell during division and is present in most bacteria. Despite exhaustive studies undertaken in the last 25 years after its discovery, we do not yet know the mechanism by which this GTP-dependent self-aggregating protein exerts force on the underlying membrane. This paper reviews recent experiments and theoretical models proposed to explain FtsZ filament dynamic assembly and force generation. It highlights how recent observations of single filaments on reconstituted model systems and computational modeling are contributing to develop new multiscale models that stress the importance of previously overlooked elements as monomer internal flexibility, filament twist and flexible anchoring to the cell membrane. These elements contribute to understand the rich behavior of these GTP consuming dynamic filaments on surfaces. The aim of this review is 2-fold: (1) to summarize recent multiscale models and their implications to understand the molecular mechanism of FtsZ assembly and force generation and (2) to update theoreticians with recent experimental results.
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Affiliation(s)
- Pablo Mateos-Gil
- Institute of Molecular Biology and Biotechnology, FO.R.T.H, Vassilika Vouton, 70013 Heraklion, Greece
| | - Pedro Tarazona
- Condensed Matter Physics Center (IFIMAC) and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Marisela Vélez
- Instituto de Catálisis y Petroleoquímica CSIC, c/ Marie Curie 2, Cantoblanco, 28049 Madrid, Spain
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9
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Schoenemann KM, Krupka M, Rowlett VW, Distelhorst SL, Hu B, Margolin W. Gain-of-function variants of FtsA form diverse oligomeric structures on lipids and enhance FtsZ protofilament bundling. Mol Microbiol 2018; 109:676-693. [PMID: 29995995 DOI: 10.1111/mmi.14069] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2018] [Indexed: 01/19/2023]
Abstract
Escherichia coli requires FtsZ, FtsA and ZipA proteins for early stages of cell division, the latter two tethering FtsZ polymers to the cytoplasmic membrane. Hypermorphic mutants of FtsA such as FtsA* (R286W) map to the FtsA self-interaction interface and can bypass the need for ZipA. Purified FtsA forms closed minirings on lipid monolayers that antagonize bundling of FtsZ protofilaments, whereas FtsA* forms smaller oligomeric arcs that enable bundling. Here, we examined three additional FtsA*-like mutant proteins for their ability to form oligomers on lipid monolayers and bundle FtsZ. Surprisingly, all three formed distinct structures ranging from mostly arcs (T249M), a mixture of minirings, arcs and straight filaments (Y139D) or short straight double filaments (G50E). All three could form filament sheets at higher concentrations with added ATP. Despite forming these diverse structures, all three mutant proteins acted like FtsA* to enable FtsZ protofilament bundling on lipid monolayers. Synthesis of the FtsA*-like proteins in vivo suppressed the toxic effects of a bundling-defective FtsZ, exacerbated effects of a hyper-bundled FtsZ, and rescued some thermosensitive cell division alleles. Together, the data suggest that conversion of FtsA minirings into any type of non-miniring oligomer can promote progression of cytokinesis through FtsZ bundling and other mechanisms.
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Affiliation(s)
- Kara M Schoenemann
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
| | - Marcin Krupka
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
| | - Veronica W Rowlett
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
| | - Steven L Distelhorst
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
| | - William Margolin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030
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10
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Guan F, Yu J, Yu J, Liu Y, Li Y, Feng XH, Huang KC, Chang Z, Ye S. Lateral interactions between protofilaments of the bacterial tubulin homolog FtsZ are essential for cell division. eLife 2018; 7:35578. [PMID: 29889022 PMCID: PMC6050046 DOI: 10.7554/elife.35578] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/10/2018] [Indexed: 01/01/2023] Open
Abstract
The prokaryotic tubulin homolog FtsZ polymerizes into protofilaments, which further assemble into higher-order structures at future division sites to form the Z-ring, a dynamic structure essential for bacterial cell division. The precise nature of interactions between FtsZ protofilaments that organize the Z-ring and their physiological significance remain enigmatic. In this study, we solved two crystallographic structures of a pair of FtsZ protofilaments, and demonstrated that they assemble in an antiparallel manner through the formation of two different inter-protofilament lateral interfaces. Our in vivo photocrosslinking studies confirmed that such lateral interactions occur in living cells, and disruption of the lateral interactions rendered cells unable to divide. The inherently weak lateral interactions enable FtsZ protofilaments to self-organize into a dynamic Z-ring. These results have fundamental implications for our understanding of bacterial cell division and for developing antibiotics that target this key process.
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Affiliation(s)
- Fenghui Guan
- Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, China.,Life Sciences Institute, Zheijiang University, Hangzhou, China
| | - Jiayu Yu
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Jie Yu
- Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, China.,Life Sciences Institute, Zheijiang University, Hangzhou, China
| | - Yang Liu
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Ying Li
- Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, China
| | - Xin-Hua Feng
- Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, China.,Life Sciences Institute, Zheijiang University, Hangzhou, China
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, United States.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Zengyi Chang
- The State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Sheng Ye
- Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, China.,Life Sciences Institute, Zheijiang University, Hangzhou, China
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11
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Huecas S, Ramírez-Aportela E, Vergoñós A, Núñez-Ramírez R, Llorca O, Díaz JF, Juan-Rodríguez D, Oliva MA, Castellen P, Andreu JM. Self-Organization of FtsZ Polymers in Solution Reveals Spacer Role of the Disordered C-Terminal Tail. Biophys J 2017; 113:1831-1844. [PMID: 29045877 DOI: 10.1016/j.bpj.2017.08.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/28/2017] [Accepted: 08/30/2017] [Indexed: 11/24/2022] Open
Abstract
FtsZ is a self-assembling GTPase that forms, below the inner membrane, the mid-cell Z-ring guiding bacterial division. FtsZ monomers polymerize head to tail forming tubulin-like dynamic protofilaments, whose organization in the Z-ring is an unresolved problem. Rather than forming a well-defined structure, FtsZ protofilaments laterally associate in vitro into polymorphic condensates typically imaged on surfaces. We describe here nanoscale self-organizing properties of FtsZ assemblies in solution that underlie Z-ring assembly, employing time-resolved x-ray scattering and cryo-electron microscopy. We find that FtsZ forms bundles made of loosely bound filaments of variable length and curvature. Individual FtsZ protofilaments further bend upon nucleotide hydrolysis, highlighted by the observation of some large circular structures with 2.5-5° curvature angles between subunits, followed by disassembly end-products consisting of highly curved oligomers and 16-subunit -220 Å diameter mini-rings, here observed by cryo-electron microscopy. Neighbor FtsZ filaments in bundles are laterally spaced 70 Å, leaving a gap in between. In contrast, close contact between filament core structures (∼50 Å spacing) is observed in straight polymers of FtsZ constructs lacking the C-terminal tail, which is known to provide a flexible tether essential for FtsZ functions in cell division. Changing the length of the intrinsically disordered C-tail linker modifies the interfilament spacing. We propose that the linker prevents dynamic FtsZ protofilaments in bundles from sticking to one another, holding them apart at a distance similar to the lateral spacing observed by electron cryotomography in several bacteria and liposomes. According to this model, weak interactions between curved polar FtsZ protofilaments through their the C-tails may facilitate the coherent treadmilling dynamics of membrane-associated FtsZ bundles in reconstituted systems, as well as the recently discovered movement of FtsZ clusters around bacterial Z-rings that is powered by GTP hydrolysis and guides correct septal cell wall synthesis and cell division.
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Affiliation(s)
- Sonia Huecas
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | | | | | | | - Oscar Llorca
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain; Spanish National Cancer Research Center, CNIO, Madrid, Spain
| | | | | | - María A Oliva
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Patricia Castellen
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain; Department of Chemistry, State University of Ponta Grossa, Paraná, Brazil
| | - José M Andreu
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
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12
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Three-Dimensional Superresolution Imaging of the FtsZ Ring during Cell Division of the Cyanobacterium Prochlorococcus. mBio 2017; 8:mBio.00657-17. [PMID: 29162705 PMCID: PMC5698547 DOI: 10.1128/mbio.00657-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Superresolution imaging has revealed subcellular structures and protein interactions in many organisms. However, superresolution microscopy with lateral resolution better than 100 nm has not been achieved in photosynthetic cells due to the interference of a high-autofluorescence background. Here, we developed a photobleaching method to effectively reduce the autofluorescence of cyanobacterial and plant cells. We achieved lateral resolution of ~10 nm with stochastic optical reconstruction microscopy (STORM) in the sphere-shaped cyanobacterium Prochlorococcus and the flowering plant Arabidopsis thaliana. During the cell cycle of Prochlorococcus, we characterized the three-dimensional (3D) organization of the cell division protein FtsZ, which forms a ring structure at the division site and is important for cytokinesis of bacteria and chloroplasts. Although the FtsZ ring assembly process in rod-shaped bacteria has been studied extensively, it has rarely been studied in sphere-shaped bacteria. Similarly to rod-shaped bacteria, our results with Prochlorococcus also showed the assembly of FtsZ clusters into incomplete rings and then complete rings during cell division. Differently from rod-shaped bacteria, the FtsZ ring diameter was not found to decrease during Prochlorococcus cell division. We also discovered a novel double-Z-ring structure, which may be the Z rings of two daughter cells in a predivisional mother cell. Our results showed a quantitative picture of the in vivo Z ring organization of sphere-shaped bacteria. Superresolution microscopy has not been widely used to study photosynthetic cells due to their high-autofluorescence background. Here, we developed a photobleaching method to reduce the autofluorescence of cyanobacteria and plant cells. After photobleaching, we performed superresolution imaging in the cyanobacterium Prochlorococcus and the flowering plant Arabidopsis thaliana with ~10-nm resolution, which is the highest resolution in a photosynthetic cell. With this method, we characterized the 3D organization of the cell division protein FtsZ in Prochlorococcus. We found that the morphological variation of the FtsZ ring during cell division of the sphere-shaped cyanobacterium Prochlorococcus is similar but not identical to that of rod-shaped bacteria. Our method might also be applicable to other photosynthetic organisms.
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13
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Abstract
The cytokinetic division ring of Escherichia coli comprises filaments of FtsZ tethered to the membrane by FtsA and ZipA. Previous results suggested that ZipA is a Z-ring stabilizer, since in vitro experiments it is shown that ZipA enhanced FtsZ assembly and caused the filaments to bundles. However, this function of ZipA has been challenged by recent studies. First, ZipA-induced FtsZ bundling was not significant at pH greater than 7. Second, some FtsA mutants, such as FtsA* were able to bypass the need of ZipA. We reinvestigated the interaction of FtsZ with ZipA in vitro. We found that ZipA not only stabilized and bundled straight filaments of FtsZ-GTP, but also stabilized the highly curved filaments and miniring structures formed by FtsZ-GDP. FtsA* had a similar stabilization of FtsZ-GDP minirings. Our results suggest that ZipA and FtsA* may contribute to constriction by stabilizing this miniring conformation.
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14
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Chen Y, Porter K, Osawa M, Augustus AM, Milam SL, Joshi C, Osteryoung KW, Erickson HP. The Chloroplast Tubulin Homologs FtsZA and FtsZB from the Red Alga Galdieria sulphuraria Co-assemble into Dynamic Filaments. J Biol Chem 2017; 292:5207-5215. [PMID: 28174299 DOI: 10.1074/jbc.m116.767715] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/06/2017] [Indexed: 01/09/2023] Open
Abstract
FtsZ is a homolog of eukaryotic tubulin and is present in almost all bacteria and many archaea, where it is the major cytoskeletal protein in the Z ring, required for cell division. Unlike some other cell organelles of prokaryotic origin, chloroplasts have retained FtsZ as an essential component of the division machinery. However, chloroplast FtsZs have been challenging to study because they are difficult to express and purify. To this end, we have used a FATT tag expression system to produce as soluble proteins the two chloroplast FtsZs from Galdieria sulphuraria, a thermophilic red alga. GsFtsZA and GsFtsZB assembled individually in the presence of GTP, forming large bundles of protofilaments. GsFtsZA also assembled in the presence of GDP, the first member of the FtsZ/tubulin superfamily to do so. Mixtures of GsFtsZA and GsFtsZB assembled protofilament bundles and hydrolyzed GTP at a rate approximately equal to the sum of their individual rates, suggesting a random co-assembly. GsFtsZA assembly by itself in limiting GTP gave polymers that remained stable for a prolonged time. However, when GsFtsZB was added, the co-polymers disassembled with enhanced kinetics, suggesting that the GsFtsZB regulates and enhances disassembly dynamics. GsFtsZA-mts (where mts is a membrane-targeting amphipathic helix) formed Z ring-like helices when expressed in Escherichia coli Co-expression of GsFtsZB (without an mts) gave co-assembly of both into similar helices. In summary, we provide biochemical evidence that GsFtsZA assembles as the primary scaffold of the chloroplast Z ring and that GsFtsZB co-assembly enhances polymer disassembly and dynamics.
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Affiliation(s)
- Yaodong Chen
- From the College of Life Science, Northwest University, Xi'an, ShaanXi, China 710069.,the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
| | - Katie Porter
- the Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824-1312
| | - Masaki Osawa
- the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
| | - Anne Marie Augustus
- the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
| | - Sara L Milam
- the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
| | - Chandra Joshi
- the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
| | - Katherine W Osteryoung
- the Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824-1312
| | - Harold P Erickson
- the Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina 27710-3709, and
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15
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Loose M, Zieske K, Schwille P. Reconstitution of Protein Dynamics Involved in Bacterial Cell Division. Subcell Biochem 2017; 84:419-444. [PMID: 28500535 DOI: 10.1007/978-3-319-53047-5_15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Even simple cells like bacteria have precisely regulated cellular anatomies, which allow them to grow, divide and to respond to internal or external cues with high fidelity. How spatial and temporal intracellular organization in prokaryotic cells is achieved and maintained on the basis of locally interacting proteins still remains largely a mystery. Bulk biochemical assays with purified components and in vivo experiments help us to approach key cellular processes from two opposite ends, in terms of minimal and maximal complexity. However, to understand how cellular phenomena emerge, that are more than the sum of their parts, we have to assemble cellular subsystems step by step from the bottom up. Here, we review recent in vitro reconstitution experiments with proteins of the bacterial cell division machinery and illustrate how they help to shed light on fundamental cellular mechanisms that constitute spatiotemporal order and regulate cell division.
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Affiliation(s)
- Martin Loose
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria.
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16
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Abstract
FtsZ assembles in vitro into protofilaments (pfs) that are one subunit thick and ~50 subunits long. In vivo these pfs assemble further into the Z ring, which, along with accessory division proteins, constricts to divide the cell. We have reconstituted Z rings in liposomes in vitro, using pure FtsZ that was modified with a membrane targeting sequence to directly bind the membrane. This FtsZ-mts assembled Z rings and constricted the liposomes without any accessory proteins. We proposed that the force for constriction was generated by a conformational change from straight to curved pfs. Evidence supporting this mechanism came from switching the membrane tether to the opposite side of the pf. These switched-tether pfs assembled "inside-out" Z rings, and squeezed the liposomes from the outside, as expected for the bending model. We propose three steps for the full process of cytokinesis: (a) pf bending generates a constriction force on the inner membrane, but the rigid peptidoglycan wall initially prevents any invagination; (b) downstream proteins associate to the Z ring and remodel the peptidoglycan, permitting it to follow the constricting FtsZ to a diameter of ~250 nm; the final steps of closure of the septum and membrane fusion are achieved by excess membrane synthesis and membrane fluctuations.
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Affiliation(s)
- Harold P Erickson
- Department of Cell Biology, Duke University, Durham, NC, 27710, USA.
| | - Masaki Osawa
- Department of Cell Biology, Duke University, Durham, NC, 27710, USA
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17
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Abstract
In bacteria and archaea, the most widespread cell division system is based on the tubulin homologue FtsZ protein, whose filaments form the cytokinetic Z-ring. FtsZ filaments are tethered to the membrane by anchors such as FtsA and SepF and are regulated by accessory proteins. One such set of proteins is responsible for Z-ring's spatiotemporal regulation, essential for the production of two equal-sized daughter cells. Here, we describe how our still partial understanding of the FtsZ-based cell division process has been progressed by visualising near-atomic structures of Z-rings and complexes that control Z-ring positioning in cells, most notably the MinCDE and Noc systems that act by negatively regulating FtsZ filaments. We summarise available data and how they inform mechanistic models for the cell division process.
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18
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Schumacher MA. Bacterial Nucleoid Occlusion: Multiple Mechanisms for Preventing Chromosome Bisection During Cell Division. Subcell Biochem 2017; 84:267-298. [PMID: 28500529 DOI: 10.1007/978-3-319-53047-5_9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In most bacteria cell division is driven by the prokaryotic tubulin homolog, FtsZ, which forms the cytokinetic Z ring. Cell survival demands both the spatial and temporal accuracy of this process to ensure that equal progeny are produced with intact genomes. While mechanisms preventing septum formation at the cell poles have been known for decades, the means by which the bacterial nucleoid is spared from bisection during cell division, called nucleoid exclusion (NO), have only recently been deduced. The NO theory was originally posited decades ago based on the key observation that the cell division machinery appeared to be inhibited from forming near the bacterial nucleoid. However, what might drive the NO process was unclear. Within the last 10 years specific proteins have been identified as important mediators of NO. Arguably the best studied NO mechanisms are those employed by the Escherichia coli SlmA and Bacillus subtilis Noc proteins. Both proteins bind specific DNA sequences within selected chromosomal regions to act as timing devices. However, Noc and SlmA contain completely different structural folds and utilize distinct NO mechanisms. Recent studies have identified additional processes and factors that participate in preventing nucleoid septation during cell division. These combined data show multiple levels of redundancy as well as a striking diversity of mechanisms have evolved to protect cells against catastrophic bisection of the nucleoid. Here we discuss these recent findings with particular emphasis on what is known about the molecular underpinnings of specific NO machinery and processes.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, 243 Nanaline H. Duke, Durham, NC, 27710, USA.
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19
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Probing for Binding Regions of the FtsZ Protein Surface through Site-Directed Insertions: Discovery of Fully Functional FtsZ-Fluorescent Proteins. J Bacteriol 2016; 199:JB.00553-16. [PMID: 27795325 DOI: 10.1128/jb.00553-16] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/04/2016] [Indexed: 11/20/2022] Open
Abstract
FtsZ, a bacterial tubulin homologue, is a cytoskeletal protein that assembles into protofilaments that are one subunit thick. These protofilaments assemble further to form a "Z ring" at the center of prokaryotic cells. The Z ring generates a constriction force on the inner membrane and also serves as a scaffold to recruit cell wall remodeling proteins for complete cell division in vivo One model of the Z ring proposes that protofilaments associate via lateral bonds to form ribbons; however, lateral bonds are still only hypothetical. To explore potential lateral bonding sites, we probed the surface of Escherichia coli FtsZ by inserting either small peptides or whole fluorescent proteins (FPs). Among the four lateral surfaces on FtsZ protofilaments, we obtained inserts on the front and back surfaces that were functional for cell division. We concluded that these faces are not sites of essential interactions. Inserts at two sites, G124 and R174, located on the left and right surfaces, completely blocked function, and these sites were identified as possible sites for essential lateral interactions. However, the insert at R174 did not interfere with association of protofilaments into sheets and bundles in vitro Another goal was to find a location within FtsZ that supported insertion of FP reporter proteins while allowing the FtsZ-FPs to function as the sole source of FtsZ. We discovered one internal site, G55-Q56, where several different FPs could be inserted without impairing function. These FtsZ-FPs may provide advances for imaging Z-ring structure by superresolution techniques. IMPORTANCE One model for the Z-ring structure proposes that protofilaments are assembled into ribbons by lateral bonds between FtsZ subunits. Our study excluded the involvement of the front and back faces of the protofilament in essential interactions in vivo but pointed to two potential lateral bond sites, on the right and left sides. We also identified an FtsZ loop where various fluorescent proteins could be inserted without blocking function; these FtsZ-FPs functioned as the sole source of FtsZ. This advance provides improved tools for all fluorescence imaging of the Z ring and may be especially important for superresolution imaging.
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20
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Leisch N, Pende N, Weber PM, Gruber-Vodicka HR, Verheul J, Vischer NOE, Abby SS, Geier B, den Blaauwen T, Bulgheresi S. Asynchronous division by non-ring FtsZ in the gammaproteobacterial symbiont of Robbea hypermnestra. Nat Microbiol 2016; 2:16182. [PMID: 27723729 DOI: 10.1038/nmicrobiol.2016.182] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/26/2016] [Indexed: 11/10/2022]
Abstract
The reproduction mode of uncultivable microorganisms deserves investigation as it can largely diverge from conventional transverse binary fission. Here, we show that the rod-shaped gammaproteobacterium thriving on the surface of the Robbea hypermnestra nematode divides by FtsZ-based, non-synchronous invagination of its poles-that is, the host-attached and fimbriae-rich pole invaginates earlier than the distal one. We conclude that, in a naturally occurring animal symbiont, binary fission is host-oriented and does not require native FtsZ to polymerize into a ring at any septation stage.
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Affiliation(s)
- Nikolaus Leisch
- Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.,Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany
| | - Nika Pende
- Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Philipp M Weber
- Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | | | - Jolanda Verheul
- Bacterial Cell Biology, Swammerdam Institute of Life Sciences, Faculty of Science, University of Amsterdam, Boelelaan 1108, 1081 HZ Amsterdam, Netherlands
| | - Norbert O E Vischer
- Bacterial Cell Biology, Swammerdam Institute of Life Sciences, Faculty of Science, University of Amsterdam, Boelelaan 1108, 1081 HZ Amsterdam, Netherlands
| | - Sophie S Abby
- Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Benedikt Geier
- Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany
| | - Tanneke den Blaauwen
- Bacterial Cell Biology, Swammerdam Institute of Life Sciences, Faculty of Science, University of Amsterdam, Boelelaan 1108, 1081 HZ Amsterdam, Netherlands
| | - Silvia Bulgheresi
- Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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21
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Lyu Z, Coltharp C, Yang X, Xiao J. Influence of FtsZ GTPase activity and concentration on nanoscale Z-ring structure in vivo revealed by three-dimensional Superresolution imaging. Biopolymers 2016; 105:725-34. [PMID: 27310678 PMCID: PMC4958570 DOI: 10.1002/bip.22895] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/10/2016] [Accepted: 06/13/2016] [Indexed: 12/18/2022]
Abstract
FtsZ is an essential bacterial cytoskeletal protein that assembles into a ring-like structure (Z-ring) at midcell to carry out cytokinesis. In vitro, FtsZ exhibits polymorphism in polymerizing into different forms of filaments based on its GTPase activity, concentration, and buffer condition. In vivo, the Z-ring appeared to be punctate and heterogeneously organized, although continuous, homogenous Z-ring structures have also been observed. Understanding how the Z-ring is organized in vivo is important because it provides a structural basis for the functional role of the Z-ring in cytokinesis. Here, we assess the effects of both GTPase activity and FtsZ concentration on the organization of the Z-ring in vivo using three-dimensional (3D) superresolution microscopy. We found that the Z-ring became more homogenous when assembled in the presence of a GTPase-deficient mutant, and upon overexpression of either wt or mutant FtsZ. These results suggest that the in vivo organization of the Z-ring is largely dependent on the intrinsic polymerization properties of FtsZ, which are significantly influenced by the GTPase activity and concentration of FtsZ. Our work provides a unifying theme to reconcile previous observations of different Z-ring structures, and supports a model in which the wt Z-ring comprises loosely associated, heterogeneously distributed FtsZ clusters. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 725-734, 2016.
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Affiliation(s)
- Zhixin Lyu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD
| | - Carla Coltharp
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD
| | - Xinxing Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD
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22
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Rowlett VW, Margolin W. The bacterial divisome: ready for its close-up. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0028. [PMID: 26370940 DOI: 10.1098/rstb.2015.0028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacterial cells divide by targeting a transmembrane protein machine to the division site and regulating its assembly and disassembly so that cytokinesis occurs at the correct time in the cell cycle. The structure and dynamics of this machine (divisome) in bacterial model systems are coming more clearly into focus, thanks to incisive cell biology methods in combination with biochemical and genetic approaches. The main conserved structural element of the machine is the tubulin homologue FtsZ, which assembles into a circumferential ring at the division site that is stabilized and anchored to the inner surface of the cytoplasmic membrane by FtsZ-binding proteins. Once this ring is in place, it recruits a series of transmembrane proteins that ultimately trigger cytokinesis. This review will survey the methods used to characterize the structure of the bacterial divisome, focusing mainly on the Escherichia coli model system, as well as the challenges that remain. These methods include recent super-resolution microscopy, cryo-electron tomography and synthetic reconstitution.
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Affiliation(s)
- Veronica W Rowlett
- Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
| | - William Margolin
- Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
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23
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TerBush AD, Porzondek CA, Osteryoung KW. Functional Analysis of the Chloroplast Division Complex Using Schizosaccharomyces pombe as a Heterologous Expression System. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:275-289. [PMID: 26917361 DOI: 10.1017/s1431927616000143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chloroplast division is driven by a macromolecular complex that assembles at the midplastid. The FtsZ ring (Z ring) is the central structure in this complex, and is composed of the functionally distinct cytoskeletal proteins FtsZ1 and FtsZ2. Recent studies in the heterologous Schizosaccharomyces pombe system showed that Arabidopsis FtsZ1 and FtsZ2 filaments have distinct assembly and turnover characteristics. To further analyze these FtsZs, we employed this system to compare the assembly and dynamic properties of FtsZ1 and FtsZ2 lacking their N- and/or C-termini with those of their full-length counterparts. Our data provide evidence that the N-terminus of FtsZ2 is critical for its structural dominance over FtsZ1, and that the N- and C-termini promote polymer bundling and turnover of both FtsZs and contribute to their distinct behaviors. We also assessed how ARC6 affects FtsZ2 filament dynamics, and found that it interacts with and stabilizes FtsZ2 filaments in S. pombe independent of its presumed Z-ring tethering function in planta. Finally, we generated FtsZ1-FtsZ2 coexpression constructs to facilitate reconstitution of more complex interaction networks. Our experiments yield new insight into factors influencing FtsZ behavior and highlight the utility of S. pombe for analyzing chloroplast FtsZs and their assembly regulators.
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Affiliation(s)
- Allan D TerBush
- 1Biochemistry and Molecular Biology Graduate Program,Michigan State University,East Lansing,MI 48824,USA
| | - Chris A Porzondek
- 3Biochemistry and Molecular Biology Undergraduate Program,Michigan State University,East Lansing,MI 48824,USA
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24
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Abstract
Bacterial cytokinesis is accomplished by the essential 'divisome' machinery. The most widely conserved divisome component, FtsZ, is a tubulin homolog that polymerizes into the 'FtsZ-ring' ('Z-ring'). Previous in vitro studies suggest that Z-ring contraction serves as a major constrictive force generator to limit the progression of cytokinesis. Here, we applied quantitative superresolution imaging to examine whether and how Z-ring contraction limits the rate of septum closure during cytokinesis in Escherichia coli cells. Surprisingly, septum closure rate was robust to substantial changes in all Z-ring properties proposed to be coupled to force generation: FtsZ's GTPase activity, Z-ring density, and the timing of Z-ring assembly and disassembly. Instead, the rate was limited by the activity of an essential cell wall synthesis enzyme and further modulated by a physical divisome-chromosome coupling. These results challenge a Z-ring-centric view of bacterial cytokinesis and identify cell wall synthesis and chromosome segregation as limiting processes of cytokinesis.
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25
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Schumacher MA, Zeng W, Huang KH, Tchorzewski L, Janakiraman A. Structural and Functional Analyses Reveal Insights into the Molecular Properties of the Escherichia coli Z Ring Stabilizing Protein, ZapC. J Biol Chem 2015; 291:2485-98. [PMID: 26655719 DOI: 10.1074/jbc.m115.697037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli cell division is driven by the tubulin-like GTPase, FtsZ, which forms the cytokinetic Z-ring. The Z-ring serves as a dynamic platform for the assembly of the multiprotein divisome, which catalyzes membrane cleavage to create equal daughter cells. Several proteins effect FtsZ assembly, thereby providing spatiotemporal control over cell division. One important class of FtsZ interacting/regulatory proteins is the Z-ring-associated proteins, Zaps, which typically modulate Z-ring formation by increasing lateral interactions between FtsZ protofilaments. Strikingly, these Zap proteins show no discernable sequence similarity, suggesting that they likely harbor distinct structures and mechanisms. The 19.8-kDa ZapC in particular shows no homology to any known protein. To gain insight into ZapC function, we determined its structure to 2.15 Å and performed genetic and biochemical studies. ZapC is a monomer composed of two domains, an N-terminal α/β region and a C-terminal twisted β barrel-like domain. The structure contains two pockets, one on each domain. The N-domain pocket is lined with residues previously implicated to be important for ZapC function as an FtsZ bundler. The adjacent C-domain pocket contains a hydrophobic center surrounded by conserved basic residues. Mutagenesis analyses indicate that this pocket is critical for FtsZ binding. An extensive FtsZ binding surface is consistent with the fact that, unlike many FtsZ regulators, ZapC binds the large FtsZ globular core rather than C-terminal tail, and the presence of two adjacent pockets suggests possible mechanisms for ZapC-mediated FtsZ bundling.
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Affiliation(s)
- Maria A Schumacher
- From the Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710,
| | - Wenjie Zeng
- From the Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710
| | - Kuo-Hsiang Huang
- Department of Biology, The City College of CUNY, New York, New York 10031, and The Graduate Center of CUNY, New York, New York 10016
| | - Lukasz Tchorzewski
- Department of Biology, The City College of CUNY, New York, New York 10031, and
| | - Anuradha Janakiraman
- Department of Biology, The City College of CUNY, New York, New York 10031, and The Graduate Center of CUNY, New York, New York 10016
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26
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Remodeling of the Z-Ring Nanostructure during the Streptococcus pneumoniae Cell Cycle Revealed by Photoactivated Localization Microscopy. mBio 2015; 6:mBio.01108-15. [PMID: 26286692 PMCID: PMC4542196 DOI: 10.1128/mbio.01108-15] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ovococci form a morphological group that includes several human pathogens (enterococci and streptococci). Their shape results from two modes of cell wall insertion, one allowing division and one allowing elongation. Both cell wall synthesis modes rely on a single cytoskeletal protein, FtsZ. Despite the central role of FtsZ in ovococci, a detailed view of the in vivo nanostructure of ovococcal Z-rings has been lacking thus far, limiting our understanding of their assembly and architecture. We have developed the use of photoactivated localization microscopy (PALM) in the ovococcus human pathogen Streptococcus pneumoniae by engineering spDendra2, a photoconvertible fluorescent protein optimized for this bacterium. Labeling of endogenously expressed FtsZ with spDendra2 revealed the remodeling of the Z-ring’s morphology during the division cycle at the nanoscale level. We show that changes in the ring’s axial thickness and in the clustering propensity of FtsZ correlate with the advancement of the cell cycle. In addition, we observe double-ring substructures suggestive of short-lived intermediates that may form upon initiation of septal cell wall synthesis. These data are integrated into a model describing the architecture and the remodeling of the Z-ring during the cell cycle of ovococci. The Gram-positive human pathogen S. pneumoniae is responsible for 1.6 million deaths per year worldwide and is increasingly resistant to various antibiotics. FtsZ is a cytoskeletal protein polymerizing at midcell into a ring-like structure called the Z-ring. FtsZ is a promising new antimicrobial target, as its inhibition leads to cell death. A precise view of the Z-ring architecture in vivo is essential to understand the mode of action of inhibitory drugs (see T. den Blaauwen, J. M. Andreu, and O. Monasterio, Bioorg Chem 55:27–38, 2014, doi:10.1016/j.bioorg.2014.03.007, for a review on FtsZ inhibitors). This is notably true in ovococcoid bacteria like S. pneumoniae, in which FtsZ is the only known cytoskeletal protein. We have used superresolution microscopy to obtain molecular details of the pneumococcus Z-ring that have so far been inaccessible with conventional microscopy. This study provides a nanoscale description of the Z-ring architecture and remodeling during the division of ovococci.
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27
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Ramírez-Aportela E, López-Blanco JR, Andreu JM, Chacón P. Understanding nucleotide-regulated FtsZ filament dynamics and the monomer assembly switch with large-scale atomistic simulations. Biophys J 2015; 107:2164-76. [PMID: 25418101 DOI: 10.1016/j.bpj.2014.09.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/23/2014] [Accepted: 09/30/2014] [Indexed: 01/08/2023] Open
Abstract
Bacterial cytoskeletal protein FtsZ assembles in a head-to-tail manner, forming dynamic filaments that are essential for cell division. Here, we study their dynamics using unbiased atomistic molecular simulations from representative filament crystal structures. In agreement with experimental data, we find different filament curvatures that are supported by a nucleotide-regulated hinge motion between consecutive FtsZ monomers. Whereas GTP-FtsZ filaments bend and twist in a preferred orientation, thereby burying the nucleotide, the differently curved GDP-FtsZ filaments exhibit a heterogeneous distribution of open and closed interfaces between monomers. We identify a coordinated Mg(2+) ion as the key structural element in closing the nucleotide site and stabilizing GTP filaments, whereas the loss of the contacts with loop T7 from the next monomer in GDP filaments leads to open interfaces that are more prone to depolymerization. We monitored the FtsZ monomer assembly switch, which involves opening/closing of the cleft between the C-terminal domain and the H7 helix, and observed the relaxation of isolated and filament minus-end monomers into the closed-cleft inactive conformation. This result validates the proposed switch between the low-affinity monomeric closed-cleft conformation and the active open-cleft FtsZ conformation within filaments. Finally, we observed how the antibiotic PC190723 suppresses the disassembly switch and allosterically induces closure of the intermonomer interfaces, thus stabilizing the filament. Our studies provide detailed structural and dynamic insights into modulation of both the intrinsic curvature of the FtsZ filaments and the molecular switch coupled to the high-affinity end-wise association of FtsZ monomers.
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Affiliation(s)
- Erney Ramírez-Aportela
- Department of Biological Physical Chemistry, Instituto de Química-Física Rocasolano, CSIC, Madrid, Spain; Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - José Ramón López-Blanco
- Department of Biological Physical Chemistry, Instituto de Química-Física Rocasolano, CSIC, Madrid, Spain
| | - José Manuel Andreu
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Pablo Chacón
- Department of Biological Physical Chemistry, Instituto de Química-Física Rocasolano, CSIC, Madrid, Spain.
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Broughton CE, Roper DI, Van Den Berg HA, Rodger A. Bacterial cell division: experimental and theoretical approaches to the divisome. Sci Prog 2015; 98:313-45. [PMID: 26790174 PMCID: PMC10365498 DOI: 10.3184/003685015x14461391862881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cell division is a key event in the bacterial life cycle. It involves constriction at the midcell, so that one cell can give rise to two daughter cells. This constriction is mediated by a ring composed offibrous multimers of the protein FtsZ. However a host of additional factors is involved in the formation and dynamics of this "Z-ring" and this complicated apparatus is collectively known as the "divisome". We review the literature, with an emphasis on mathematical modelling, and show how such theoretical efforts have helped experimentalists to make sense of the at times bewildering data, and plan further experiments.
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Szwedziak P, Wang Q, Bharat TAM, Tsim M, Löwe J. Architecture of the ring formed by the tubulin homologue FtsZ in bacterial cell division. eLife 2014; 3:e04601. [PMID: 25490152 PMCID: PMC4383033 DOI: 10.7554/elife.04601] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/08/2014] [Indexed: 12/16/2022] Open
Abstract
Membrane constriction is a prerequisite for cell division. The most common membrane
constriction system in prokaryotes is based on the tubulin homologue FtsZ, whose
filaments in E. coli are anchored to the membrane by FtsA and enable
the formation of the Z-ring and divisome. The precise architecture of the FtsZ ring
has remained enigmatic. In this study, we report three-dimensional arrangements of
FtsZ and FtsA filaments in C. crescentus and E.
coli cells and inside constricting liposomes by means of electron
cryomicroscopy and cryotomography. In vivo and in vitro, the Z-ring is composed of a
small, single-layered band of filaments parallel to the membrane, creating a
continuous ring through lateral filament contacts. Visualisation of the in vitro
reconstituted constrictions as well as a complete tracing of the helical paths of the
filaments with a molecular model favour a mechanism of FtsZ-based membrane
constriction that is likely to be accompanied by filament sliding. DOI:http://dx.doi.org/10.7554/eLife.04601.001 Cell division is the process by which new cells are made. It is therefore vital for
the growth and development, and the regeneration and repair of damaged tissues. When
bacterial and animal cells divide, they must constrict their membrane inwards to
split a single cell into two. In most bacteria, this constriction is guided by a
ring-like structure that contains filaments of a protein called FtsZ. During cell
division, this structure forms around the inside edge of the cell and when it
contracts, it pulls the membrane inwards and causes the cell to constrict and
eventually divide. In recent years, this arrangement of FtsZ filaments has been intensively
investigated, giving rise to various theories about how it is made and how it works:
for example, some recent studies suggested that FtsZ does not form a continuous ring.
Nevertheless, many details about the cell division process remain unknown. Szwedziak, Wang et al. have now investigated this protein ring in two species of
bacteria by turning to advanced forms of microscopy to closely observe its structure
and how it works. This included mapping the ring in three dimensions. Contrary to
earlier reports that the FtsZ ring is discontinuous, in both a bacterium called
Caulobacter crescentus and another called Escherichia
coli, the ring forms a continuous shape made up of overlapping
filaments. Szwedziak, Wang et al. then increased the levels of two of the ring's main
components: the FtsZ protein that forms the filaments and a protein that anchors
these filaments to the cell membrane. This caused the modified cells to constrict and
divide at extra sites, which resulted in the formation of abnormally small cells.
These findings suggest that these two ring components by themselves are able to
generate both the structures and force required for cell constriction. This is
supported by the fact that when they were introduced into artificial cell-like
structures, these proteins spontaneously self-organised into rings and triggered
constriction where they formed. Szwedziak, Wang et al. propose that constriction only starts once the FtsZ protein
forms a closed ring and that the ring's overlapping filaments slide along each other
to further decrease its diameter and constrict the cell. The degree of filament
overlap likely also increases with constriction, requiring filaments to be shortened
to maintain sliding. This shortening, along with sliding, could provide a mechanism
by which to drive the constriction process. This work will be followed by even more detailed studies in order to understand the
process of bacterial cell division at the atomic scale and how the cell's wall is
reshaped during the process. In the long run, intricate knowledge of how a bacterial
cell divides might enable the design of new classes of antibiotics targeting the
molecular machinery involved. DOI:http://dx.doi.org/10.7554/eLife.04601.002
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Affiliation(s)
- Piotr Szwedziak
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Qing Wang
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Tanmay A M Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Matthew Tsim
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Jan Löwe
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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Barclay TG, Constantopoulos K, Matisons J. Nanotubes Self-Assembled from Amphiphilic Molecules via Helical Intermediates. Chem Rev 2014; 114:10217-91. [DOI: 10.1021/cr400085m] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Thomas G. Barclay
- Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide, South Australia 5042, Australia
| | - Kristina Constantopoulos
- Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide, South Australia 5042, Australia
| | - Janis Matisons
- Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide, South Australia 5042, Australia
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31
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Jagannathan S, Hsu JCC, Reid DW, Chen Q, Thompson WJ, Moseley AM, Nicchitta CV. Multifunctional roles for the protein translocation machinery in RNA anchoring to the endoplasmic reticulum. J Biol Chem 2014; 289:25907-24. [PMID: 25063809 DOI: 10.1074/jbc.m114.580688] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Signal sequence-encoding mRNAs undergo translation-dependent localization to the endoplasmic reticulum (ER) and at the ER are anchored via translation on Sec61-bound ribosomes. Recent investigations into the composition and membrane association characteristics of ER-associated mRNAs have, however, revealed both ribosome-dependent (indirect) and ribosome-independent (direct) modes of mRNA association with the ER. These findings raise important questions regarding our understanding of how mRNAs are selected, localized, and anchored to the ER. Using semi-intact tissue culture cells, we performed a polysome solubilization screen and identified conditions that distinguish polysomes engaged in the translation of distinct cohorts of mRNAs. To gain insight into the molecular basis of direct mRNA anchoring to the ER, we performed RNA-protein UV photocross-linking studies in rough microsomes and demonstrate that numerous ER integral membrane proteins display RNA binding activity. Quantitative proteomic analyses of HeLa cytosolic and ER-bound polysome fractions identified translocon components as selective polysome-interacting proteins. Notably, the Sec61 complex was highly enriched in polysomes engaged in the translation of endomembrane organelle proteins, whereas translocon accessory proteins, such as ribophorin I, were present in all subpopulations of ER-associated polysomes. Analyses of the protein composition of oligo(dT)-selected UV photocross-linked ER protein-RNA adducts identified Sec61α,β and ribophorin I as ER-poly(A) mRNA-binding proteins, suggesting unexpected roles for the protein translocation and modification machinery in mRNA anchoring to the ER. In summary, we propose that multiple mechanisms of mRNA and ribosome association with ER operate to enable an mRNA transcriptome-wide function for the ER in protein synthesis.
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Affiliation(s)
| | | | | | - Qiang Chen
- From the Departments of Cell Biology and
| | - Will J Thompson
- the Duke Proteomics Core Facility, Duke University Medical Center, Durham, North Carolina 27710
| | - Arthur M Moseley
- the Duke Proteomics Core Facility, Duke University Medical Center, Durham, North Carolina 27710
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32
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MinCDE exploits the dynamic nature of FtsZ filaments for its spatial regulation. Proc Natl Acad Sci U S A 2014; 111:E1192-200. [PMID: 24707052 DOI: 10.1073/pnas.1317764111] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In Escherichia coli, a contractile ring (Z-ring) is formed at midcell before cytokinesis. This ring consists primarily of FtsZ, a tubulin-like GTPase, that assembles into protofilaments similar to those in microtubules but different in their suprastructures. The Min proteins MinC, MinD, and MinE are determinants of Z-ring positioning in E. coli. MinD and MinE oscillate from pole to pole, and genetic and biochemical evidence concludes that MinC positions the Z-ring by coupling its assembly to the oscillations by direct inhibitory interaction. The mechanism of inhibition of FtsZ polymerization and, thus, positioning by MinC, however, is not understood completely. Our in vitro reconstitution experiments suggest that the Z-ring consists of dynamic protofilament bundles in which monomers constantly are exchanged throughout, stochastically creating protofilament ends along the length of the filament. From the coreconstitution of FtsZ with MinCDE, we propose that MinC acts on the filaments in two ways: by increasing the detachment rate of FtsZ-GDP within the filaments and by reducing the attachment rate of FtsZ monomers to filaments by occupying binding sites on the FtsZ filament lattice. Furthermore, our data show that the MinCDE system indeed is sufficient to cause spatial regulation of FtsZ, required for Z-ring positioning.
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High throughput 3D super-resolution microscopy reveals Caulobacter crescentus in vivo Z-ring organization. Proc Natl Acad Sci U S A 2014; 111:4566-71. [PMID: 24616530 DOI: 10.1073/pnas.1313368111] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We created a high-throughput modality of photoactivated localization microscopy (PALM) that enables automated 3D PALM imaging of hundreds of synchronized bacteria during all stages of the cell cycle. We used high-throughput PALM to investigate the nanoscale organization of the bacterial cell division protein FtsZ in live Caulobacter crescentus. We observed that FtsZ predominantly localizes as a patchy midcell band, and only rarely as a continuous ring, supporting a model of "Z-ring" organization whereby FtsZ protofilaments are randomly distributed within the band and interact only weakly. We found evidence for a previously unidentified period of rapid ring contraction in the final stages of the cell cycle. We also found that DNA damage resulted in production of high-density continuous Z-rings, which may obstruct cytokinesis. Our results provide a detailed quantitative picture of in vivo Z-ring organization.
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34
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Form and function of the bacterial cytokinetic ring. Curr Opin Cell Biol 2014; 26:19-27. [DOI: 10.1016/j.ceb.2013.08.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/29/2013] [Accepted: 08/30/2013] [Indexed: 01/01/2023]
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35
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Buss J, Coltharp C, Huang T, Pohlmeyer C, Wang SC, Hatem C, Xiao J. In vivo organization of the FtsZ-ring by ZapA and ZapB revealed by quantitative super-resolution microscopy. Mol Microbiol 2013; 89:1099-120. [PMID: 23859153 PMCID: PMC3894617 DOI: 10.1111/mmi.12331] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2013] [Indexed: 12/13/2022]
Abstract
In most bacterial cells, cell division is dependent on the polymerization of the FtsZ protein to form a ring-like structure (Z-ring) at the midcell. Despite its essential role, the molecular architecture of the Z-ring remains elusive. In this work we examine the roles of two FtsZ-associated proteins, ZapA and ZapB, in the assembly dynamics and structure of the Z-ring in Escherichia coli cells. In cells deleted of zapA or zapB, we observed abnormal septa and highly dynamic FtsZ structures. While details of these FtsZ structures are difficult to discern under conventional fluorescence microscopy, single-molecule-based super-resolution imaging method Photoactivated Localization Microscopy (PALM) reveals that these FtsZ structures arise from disordered arrangements of FtsZ clusters. Quantitative analysis finds these clusters are larger and comprise more molecules than a single FtsZ protofilament, and likely represent a distinct polymeric species that is inherent to the assembly pathway of the Z-ring. Furthermore, we find these clusters are not due to the loss of ZapB-MatP interaction in ΔzapA and ΔzapB cells. Our results suggest that the main function of ZapA and ZapB in vivo may not be to promote the association of individual protofilaments but to align FtsZ clusters that consist of multiple FtsZ protofilaments.
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Affiliation(s)
- Jackson Buss
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Carla Coltharp
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Tao Huang
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Chris Pohlmeyer
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shih-Chin Wang
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Christine Hatem
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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36
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Jiménez M, Martos A, Cabré EJ, Raso A, Rivas G. Giant vesicles: a powerful tool to reconstruct bacterial division assemblies in cell-like compartments. Environ Microbiol 2013; 15:3158-68. [DOI: 10.1111/1462-2920.12214] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Mercedes Jiménez
- Centro de Investigaciones Biológicas; CSIC; c/Ramiro de Maeztu 9 28040 Madrid Spain
| | - Ariadna Martos
- Max Planck Institute of Biochemistry; Am Klopferspitz 18 D-82152 Martinsried Germany
| | - Elisa J. Cabré
- Centro de Investigaciones Biológicas; CSIC; c/Ramiro de Maeztu 9 28040 Madrid Spain
| | - Ana Raso
- Centro de Investigaciones Biológicas; CSIC; c/Ramiro de Maeztu 9 28040 Madrid Spain
- Max Planck Institute of Biochemistry; Am Klopferspitz 18 D-82152 Martinsried Germany
| | - Germán Rivas
- Centro de Investigaciones Biológicas; CSIC; c/Ramiro de Maeztu 9 28040 Madrid Spain
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37
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Milam SL, Erickson HP. Rapid in vitro assembly of Caulobacter crescentus FtsZ protein at pH 6.5 and 7.2. J Biol Chem 2013; 288:23675-9. [PMID: 23824192 DOI: 10.1074/jbc.m113.491845] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FtsZ from most bacteria assembles rapidly in vitro, reaching a steady-state plateau in 5-10 s after addition of GTP. A recent study used a novel dynamic light-scattering technique to assay the assembly of FtsZ from Caulobacter crescentus (CcFtsZ) and reported that assembly required 10 min, ∼100 times slower than for related bacteria. Previous studies had indicated normal, rapid assembly of CcFtsZ. We have reinvestigated the assembly kinetics using a mutant L72W, where assembly of subunits into protofilaments results in a significant increase in tryptophan fluorescence. We found that assembly reached a plateau in 5-10 s and showed no change in the following 10 min. This was confirmed by 90° light scattering and negative-stain electron microscopy. The very slow kinetics in the dynamic light-scattering study may be related to a refractory state induced when the FtsZ protein is stored without nucleotide, a phenomenon that we had observed in a previous study of EcFtsZ. We conclude that CcFtsZ is not an outlier, but shows rapid assembly kinetics similar to FtsZ from related bacteria.
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Affiliation(s)
- Sara L Milam
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27701-3709, USA
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38
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Gardner KAJA, Moore DA, Erickson HP. The C-terminal linker of Escherichia coli FtsZ functions as an intrinsically disordered peptide. Mol Microbiol 2013; 89:264-75. [PMID: 23714328 DOI: 10.1111/mmi.12279] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2013] [Indexed: 11/28/2022]
Abstract
The tubulin homologue FtsZ provides the cytoskeletal framework and constriction force for bacterial cell division. FtsZ has an 50-amino-acid (aa) linker between the protofilament-forming globular domain and the C-terminal (Ct) peptide that binds FtsA and ZipA, tethering FtsZ to the membrane. This Ct-linker is widely divergent across bacterial species and thought to be an intrinsically disordered peptide (IDP). We confirmed that the Ct-linkers from three bacterial species behaved as IDPs in vitro by circular dichroism and trypsin proteolysis. We made chimeras, swapping the Escherichia coli linker for Ct-linkers from other bacteria, and even for an unrelated IDP from human α-adducin. Most substitutions allowed for normal cell division, suggesting that sequence of the IDP did not matter. With few exceptions, almost any sequence appears to work. Length, however, was important: IDPs shorter than 43 or longer than 95 aa had compromised or no function. We conclude that the Ct-linker functions as a flexible tether between the globular domain of FtsZ in the protofilament, and its attachment to FtsA/ZipA at the membrane. Modelling the Ct-linker as a worm-like chain, we predict that it functions as a stiff entropic spring linking the bending protofilaments to the membrane.
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39
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Rico AI, Krupka M, Vicente M. In the beginning, Escherichia coli assembled the proto-ring: an initial phase of division. J Biol Chem 2013; 288:20830-20836. [PMID: 23740256 DOI: 10.1074/jbc.r113.479519] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cell division in Escherichia coli begins by assembling three proteins, FtsZ, FtsA, and ZipA, to form a proto-ring at midcell. These proteins nucleate an assembly of at least 35 components, the divisome. The structuring of FtsZ to form a ring and the processes that effect constriction have been explained by alternative but not mutually exclusive mechanisms. We discuss how FtsA and ZipA provide anchoring of the cytoplasmic FtsZ to the membrane and how a temporal sequence of alternative protein interactions may operate in the maturation and stability of the proto-ring. How the force needed for constriction is generated and how the proto-ring proteins relate to peptidoglycan synthesis remain as the main challenges for future research.
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Affiliation(s)
- Ana Isabel Rico
- From the Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain
| | - Marcin Krupka
- From the Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain
| | - Miguel Vicente
- From the Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain.
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40
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Abstract
Far from being simple 'bags' of enzymes, bacteria are richly endowed with ultrastructures that challenge and expand standard definitions of the cytoskeleton. Here we review rods, rings, twisted pairs, tubes, sheets, spirals, moving patches, meshes and composites, and suggest defining the term 'bacterial cytoskeleton' as all cytoplasmic protein filaments and their superstructures that move or scaffold (stabilize/position/recruit) other cellular materials. The evolution of each superstructure has been driven by specific functional requirements. As a result, while homologous proteins with different functions have evolved to form surprisingly divergent superstructures, those of unrelated proteins with similar functions have converged.
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Affiliation(s)
- Martin Pilhofer
- Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, 1200 E California Blvd, M/C 114-96, Pasadena, CA, USA.
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41
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TerBush AD, Osteryoung KW. Distinct functions of chloroplast FtsZ1 and FtsZ2 in Z-ring structure and remodeling. J Cell Biol 2012; 199:623-37. [PMID: 23128242 PMCID: PMC3494859 DOI: 10.1083/jcb.201205114] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 10/12/2012] [Indexed: 12/19/2022] Open
Abstract
FtsZ, a cytoskeletal GTPase, forms a contractile ring for cell division in bacteria and chloroplast division in plants. Whereas bacterial Z rings are composed of a single FtsZ, those in chloroplasts contain two distinct FtsZ proteins, FtsZ1 and FtsZ2, whose functional relationship is poorly understood. We expressed fluorescently tagged FtsZ1 and FtsZ2 in fission yeast to investigate their intrinsic assembly and dynamic properties. FtsZ1 and FtsZ2 formed filaments with differing morphologies when expressed separately. FRAP showed that FtsZ2 filaments were less dynamic than FtsZ1 filaments and that GTPase activity was essential for FtsZ2 filament turnover but may not be solely responsible for FtsZ1 turnover. When coexpressed, the proteins colocalized, consistent with coassembly, but exhibited an FtsZ2-like morphology. However, FtsZ1 increased FtsZ2 exchange into coassembled filaments. Our findings suggest that FtsZ2 is the primary determinant of chloroplast Z-ring structure, whereas FtsZ1 facilitates Z-ring remodeling. We also demonstrate that ARC3, a regulator of chloroplast Z-ring positioning, functions as an FtsZ1 assembly inhibitor.
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Affiliation(s)
- Allan D. TerBush
- Biochemistry and Molecular Biology Graduate Program and Department of Plant Biology, Michigan State University, East Lansing, MI 48824
| | - Katherine W. Osteryoung
- Biochemistry and Molecular Biology Graduate Program and Department of Plant Biology, Michigan State University, East Lansing, MI 48824
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