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Martínez-Torró C, Torres-Puig S, Marcos-Silva M, Huguet-Ramón M, Muñoz-Navarro C, Lluch-Senar M, Serrano L, Querol E, Piñol J, Pich OQ. Functional Characterization of the Cell Division Gene Cluster of the Wall-less Bacterium Mycoplasma genitalium. Front Microbiol 2021; 12:695572. [PMID: 34589065 PMCID: PMC8475190 DOI: 10.3389/fmicb.2021.695572] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/10/2021] [Indexed: 12/03/2022] Open
Abstract
It is well-established that FtsZ drives peptidoglycan synthesis at the division site in walled bacteria. However, the function and conservation of FtsZ in wall-less prokaryotes such as mycoplasmas are less clear. In the genome-reduced bacterium Mycoplasma genitalium, the cell division gene cluster is limited to four genes: mraZ, mraW, MG_223, and ftsZ. In a previous study, we demonstrated that ftsZ was dispensable for growth of M. genitalium under laboratory culture conditions. Herein, we show that the entire cell division gene cluster of M. genitalium is non-essential for growth in vitro. Our analyses indicate that loss of the mraZ gene alone is more detrimental for growth of M. genitalium than deletion of ftsZ or the entire cell division gene cluster. Transcriptional analysis revealed a marked upregulation of ftsZ in the mraZ mutant. Stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics confirmed the overexpression of FtsZ in MraZ-deprived cells. Of note, we found that ftsZ expression was upregulated in non-adherent cells of M. genitalium, which arise spontaneously at relatively high rates. Single cell analysis using fluorescent markers showed that FtsZ localization varied throughout the cell cycle of M. genitalium in a coordinated manner with the chromosome and the terminal organelle (TMO). In addition, our results indicate a possible role for the RNA methyltransferase MraW in the regulation of FtsZ expression at the post-transcriptional level. Altogether, this study provides an extensive characterization of the cell division gene cluster of M. genitalium and demonstrates the existence of regulatory elements controlling FtsZ expression at the temporal and spatial level in mycoplasmas.
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Affiliation(s)
- Carlos Martínez-Torró
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sergi Torres-Puig
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marina Marcos-Silva
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marta Huguet-Ramón
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Carmen Muñoz-Navarro
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Maria Lluch-Senar
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Luis Serrano
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Enrique Querol
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Jaume Piñol
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Oscar Q. Pich
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain
- Laboratori de Recerca en Microbiologia i Malalties Infeccioses, Institut d’Investigació i Innovació Parc Taulí (I3PT), Hospital Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain
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Khare S, Hsin J, Sorto NA, Nepomuceno GM, Shaw JT, Shi H, Huang KC. FtsZ-Independent Mechanism of Division Inhibition by the Small Molecule PC190723 in Escherichia coli. ACTA ACUST UNITED AC 2020; 3:e1900021. [PMID: 32648693 DOI: 10.1002/adbi.201900021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/07/2019] [Indexed: 11/12/2022]
Abstract
While cell division is a critical process in cellular proliferation, very few antibiotics have been identified that target the bacterial cell-division machinery. Recent studies have shown that the small molecule PC190723 inhibits cell division in several Gram-positive bacteria, with a hypothesized mechanism of action involving direct targeting of the tubulin homolog FtsZ, which is essential for division in virtually all bacterial species. Here, it is shown that PC190723 also inhibits cell division in the Gram-negative bacterium Escherichia coli if the outer membrane permeability barrier is compromised genetically or chemically. The results show that the equivalent FtsZ mutations conferring PC190723 resistance in Staphylococcus aureus do not protect E. coli against PC190723, and that suppressors of PC190723 sensitivity in E. coli, which do not generically decrease outer membrane permeability, do not map to FtsZ or other division proteins. These suppressors display a wide range of morphological and growth phenotypes, and one exhibits a death phenotype in the stationary phase similar to that of a mutant with disrupted lipid homeostasis. Finally, a complementing FtsZ-msfGFP fusion is used to show that PC190723 does not affect the Z-ring structure. Taken together, the findings suggest that PC190723 inhibits growth and division in E. coli without targeting FtsZ. This study highlights the importance of utilizing a combination of genetic, chemical, and single-cell approaches to dissect the mechanisms of action of new antibiotics, which are not necessarily conserved across bacterial species.
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Affiliation(s)
- Somya Khare
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Jen Hsin
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Nohemy A Sorto
- Department of Chemistry, University of California at Davis, Davis, CA, 95616, USA
| | | | - Jared T Shaw
- Department of Chemistry, University of California at Davis, Davis, CA, 95616, USA
| | - Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.,Department of Microbiology and Immunology, Stanford University, Stanford, CA, 94305, USA.,Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
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Ranjit DK, Liechti GW, Maurelli AT. Chlamydial MreB Directs Cell Division and Peptidoglycan Synthesis in Escherichia coli in the Absence of FtsZ Activity. mBio 2020; 11:e03222-19. [PMID: 32071268 PMCID: PMC7029139 DOI: 10.1128/mbio.03222-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/06/2020] [Indexed: 12/28/2022] Open
Abstract
Cell division is the ultimate process for the propagation of bacteria, and FtsZ is an essential protein used by nearly all bacteria for this function. Chlamydiae belong to a small group of bacteria that lack the universal cell division protein FtsZ but still divide by binary fission. Chlamydial MreB is a member of the shape-determining MreB/Mbl family of proteins responsible for rod shape morphology in Escherichia coliChlamydia also encodes a homolog of RodZ, an MreB assembly cytoskeletal protein that links MreB to cell wall synthesis proteins. We hypothesized that MreB directs cell division in Chlamydia and that chlamydial MreB could replace FtsZ function for cell division in E. coli Overexpression of chlamydial mreB-rodZ in E. coli induced prominent morphological changes with production of large swollen or oval bacteria, eventually resulting in bacterial lysis. Low-level expression of chlamydial mreB-rodZ restored viability of a lethal ΔmreB mutation in E. coli, although the bacteria lost their typical rod shape and grew as rounded cells. When FtsZ activity was inhibited by overexpression of SulA in the ΔmreB mutant of E. coli complemented with chlamydial mreB-rodZ, spherical E. coli grew and divided. Localization studies using a fluorescent fusion chlamydial MreB protein indicated that chlamydial RodZ directs chlamydial MreB to the E. coli division septum. These results demonstrate that chlamydial MreB, in partnership with chlamydial RodZ, acts as a cell division protein. Our findings suggest that an mreB-rodZ-based mechanism allows Chlamydia to divide without the universal division protein FtsZ.IMPORTANCE The study of Chlamydia growth and cell division is complicated by its obligate intracellular nature and biphasic lifestyle. Chlamydia also lacks the universal division protein FtsZ. We employed the cell division system of Escherichia coli as a surrogate to identify chlamydial cell division proteins. We demonstrate that chlamydial MreB, together with chlamydial RodZ, forms a cell division and growth complex that can replace FtsZ activity and support cell division in E. coli Chlamydial RodZ plays a major role in directing chlamydial MreB localization to the cell division site. It is likely that the evolution of chlamydial MreB and RodZ to form a functional cell division complex allowed Chlamydia to dispense with its FtsZ-based cell division machinery during genome reduction. Thus, MreB-RodZ represents a possible mechanism for cell division in other bacteria lacking FtsZ.
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Affiliation(s)
- Dev K Ranjit
- Emerging Pathogens Institute and Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
| | - George W Liechti
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Anthony T Maurelli
- Emerging Pathogens Institute and Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
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Osawa M, Erickson HP. Turgor Pressure and Possible Constriction Mechanisms in Bacterial Division. Front Microbiol 2018; 9:111. [PMID: 29445369 PMCID: PMC5797765 DOI: 10.3389/fmicb.2018.00111] [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: 11/19/2017] [Accepted: 01/17/2018] [Indexed: 12/15/2022] Open
Abstract
Bacterial cytokinesis begins with the assembly of FtsZ into a Z ring at the center of the cell. The Z-ring constriction in Gram-negative bacteria may occur in an environment where the periplasm and the cytoplasm are isoosmotic, but in Gram-positive bacteria the constriction may have to overcome a substantial turgor pressure. We address three potential sources of invagination force. (1) FtsZ itself may generate force by curved protofilaments bending the attached membrane. This is sufficient to constrict liposomes in vitro. However, this force is on the order of a few pN, and would not be enough to overcome turgor. (2) Cell wall (CW) synthesis may generate force by pushing the plasma membrane from the outside. However, this would probably require some kind of Brownian ratchet to separate the CW and membrane sufficiently to allow a glycan strand to slip in. The elastic element is not obvious. (3) Excess membrane production has the potential to contribute significantly to the invagination force. If the excess membrane is produced under the CW, it would force the membrane to bleb inward. We propose here that a combination of FtsZ pulling from the inside, and excess membrane pushing membrane inward may generate a substantial constriction force at the division site. This combined force generation mechanism may be sufficient to overcome turgor pressure. This would abolish the need for a Brownian ratchet for CW growth, and would permit CW to operate by reinforcing the constrictions generated by FtsZ and excess membrane.
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Affiliation(s)
- Masaki Osawa
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
| | - Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, United States
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5
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ARC6-mediated Z ring-like structure formation of prokaryote-descended chloroplast FtsZ in Escherichia coli. Sci Rep 2017; 7:3492. [PMID: 28615720 PMCID: PMC5471200 DOI: 10.1038/s41598-017-03698-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/04/2017] [Indexed: 12/04/2022] Open
Abstract
Plant chloroplasts proliferate through binary fission, and the stromal-side molecules that are involved in chloroplast division are bacterial derivatives. As in bacteria, the prokaryotic tubulin homolog FtsZ assembles into a ring-like structure (Z ring) at mid-chloroplast, and this process is followed by constriction. However, the properties of chloroplast FtsZs remain unclarified. Here, we employed Escherichia coli as a novel heterologous system for expressing chloroplast FtsZs and their regulatory components. Fluorescently labelled Arabidopsis FtsZ2 efficiently assembled into long filaments in E. coli cells, and artificial membrane tethering conferred FtsZ2 filaments with the ability to form Z ring-like structures resembling the bacterial Z ring. A negative regulator of chloroplast FtsZ assembly, ARC3, retained its inhibitory effects on FtsZ2 filamentation and Z ring-like structure formation in E. coli cells. Thus, we provide a novel heterologous system by using bacterial cells to study the regulation of the chloroplast divisome. Furthermore, we demonstrated that the FtsZ2-interacting protein ARC6, which is a potential candidate for Z ring tethering to the chloroplast inner envelope membrane, genuinely targeted FtsZ2 to the membrane components and supported its morphological shift from linear filaments to Z ring-like structures in a manner dependent on the C-terminal ARC6-interacting domain of FtsZ2.
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6
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Gardner KAJA, Osawa M, Erickson HP. Whole genome re-sequencing to identify suppressor mutations of mutant and foreign Escherichia coli FtsZ. PLoS One 2017; 12:e0176643. [PMID: 28445510 PMCID: PMC5405962 DOI: 10.1371/journal.pone.0176643] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/13/2017] [Indexed: 01/07/2023] Open
Abstract
FtsZ is an essential protein for bacterial cell division, where it forms the cytoskeletal scaffold and may generate the constriction force. We have found previously that some mutant and foreign FtsZ that do not complement an ftsZ null can function for cell division in E. coli upon acquisition of a suppressor mutation somewhere in the genome. We have now identified, via whole genome re-sequencing, single nucleotide polymorphisms in 11 different suppressor strains. Most of the mutations are in genes of various metabolic pathways, which may modulate cell division indirectly. Mutations in three genes, ispA, accD and nlpI, may be more directly involved in cell division. In addition to the genomic suppressor mutations, we identified intragenic suppressors of three FtsZ point mutants (R174A, E250K and L272V).
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Affiliation(s)
- Kiani A. J. Arkus Gardner
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Masaki Osawa
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Harold P. Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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7
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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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8
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Vedyaykin AD, Sabantsev AV, Khodorkovskii MA, Kayumov AR, Vishnyakov IE. Recombinant FtsZ Proteins from Mollicutes Interact with Escherichia coli Division Machinery. BIONANOSCIENCE 2016. [DOI: 10.1007/s12668-016-0248-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Bohuszewicz O, Liu J, Low HH. Membrane remodelling in bacteria. J Struct Biol 2016; 196:3-14. [PMID: 27265614 PMCID: PMC6168058 DOI: 10.1016/j.jsb.2016.05.010] [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: 03/07/2016] [Revised: 05/20/2016] [Accepted: 05/26/2016] [Indexed: 01/10/2023]
Abstract
In bacteria the ability to remodel membrane underpins basic cell processes such as growth, and more sophisticated adaptations like inter-cell crosstalk, organelle specialisation, and pathogenesis. Here, selected examples of membrane remodelling in bacteria are presented and the diverse mechanisms for inducing membrane fission, fusion, and curvature discussed. Compared to eukaryotes, relatively few curvature-inducing proteins have been characterised so far. Whilst it is likely that many such proteins remain to be discovered, it also reflects the importance of alternative membrane remodelling strategies in bacteria where passive mechanisms for generating curvature are utilised.
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Affiliation(s)
- Olga Bohuszewicz
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Jiwei Liu
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Harry H Low
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK.
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Housman M, Milam SL, Moore DA, Osawa M, Erickson HP. FtsZ Protofilament Curvature Is the Opposite of Tubulin Rings. Biochemistry 2016; 55:4085-91. [PMID: 27368355 DOI: 10.1021/acs.biochem.6b00479] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
FtsZ protofilaments (pfs) form the bacterial cytokinetic Z ring. Previous work suggested that a conformational change from straight to curved pfs generated the constriction force. In the simplest model, the C-terminal membrane tether is on the outside of the curved pf, facing the membrane. Tubulin, a homologue of FtsZ, also forms pfs with a curved conformation. However, it is well-established that tubulin rings have the C terminus on the inside of the ring. Could FtsZ and tubulin rings have the opposite curvature? In this study, we explored the FtsZ curvature direction by fusing large protein tags to the FtsZ termini. Thin section electron microscopy showed that the C-terminal tag was on the outside, consistent with the bending pf model. This has interesting implications for the evolution of tubulin. Tubulin likely began with the curvature of FtsZ, but evolution managed to reverse direction to produce outward-curving rings, which are useful for pulling chromosomes.
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Affiliation(s)
- Max Housman
- Department of Cell Biology, Duke University, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Sara L Milam
- Department of Cell Biology, Duke University, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Desmond A Moore
- Department of Cell Biology, Duke University, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Masaki Osawa
- Department of Cell Biology, Duke University, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Harold P Erickson
- Department of Cell Biology, Duke University, Duke University Medical Center , Durham, North Carolina 27710, United States
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11
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González de Prado Salas P, Tarazona P. Collective effects of torsion in FtsZ filaments. Phys Rev E 2016; 93:042407. [PMID: 27176329 DOI: 10.1103/physreve.93.042407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Indexed: 11/07/2022]
Abstract
Recent evidence points to the presence of torsion in FtsZ bonds. In addition, experiments with FtsZ mutants on surfaces resulted in new aggregates that cannot be explained by older models for FtsZ dynamics. We use an interaction model for FtsZ derived from molecular dynamics simulations and expand a fine-grained lattice model used to describe FtsZ aggregates on a surface. This new model includes different anchoring angles for the monomers and allows bond twist, two ingredients that oppose each other resulting in a more dynamic and interesting system. We study the role and importance of these conflicting elements and how the aggregates are characterized by the different interaction parameters.
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Affiliation(s)
| | - Pedro Tarazona
- Departamento de Física Teórica de la Materia Condensada, Condensed Matter Physics Institute (IFIMAC) and Instituto de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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12
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Balish MF, Distelhorst SL. Potential Molecular Targets for Narrow-Spectrum Agents to Combat Mycoplasma pneumoniae Infection and Disease. Front Microbiol 2016; 7:205. [PMID: 26941728 PMCID: PMC4766277 DOI: 10.3389/fmicb.2016.00205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/08/2016] [Indexed: 12/17/2022] Open
Abstract
As Mycoplasma pneumoniae macrolide resistance grows and spreads worldwide, it is becoming more important to develop new drugs to prevent infection or limit disease. Because other mycoplasma species have acquired resistance to other classes of antibiotics, it is reasonable to presume that M. pneumoniae can do the same, so switching to commonly used antibiotics like fluoroquinolones will not result in forms of therapy with long-term utility. Moreover, broad-spectrum antibiotics can have serious consequences for the patient, as these drugs may have severe impacts on the natural microbiota of the individual, compromising the health of the patient either short-term or long-term. Therefore, developing narrow-spectrum antibiotics that effectively target only M. pneumoniae and no more than a small portion of the microbiota is likely to yield impactful, positive results that can be used perhaps indefinitely to combat M. pneumoniae. Development of these agents requires a deep understanding of the basic biology of M. pneumoniae, in many areas deeper than what is currently known. In this review, we discuss potential targets for new, narrow-spectrum agents and both the positive and negative aspects of selecting these targets, which include toxic molecules, metabolic pathways, and attachment and motility. By gathering this information together, we anticipate that it will be easier for researchers to evaluate topics of priority for study of M. pneumoniae.
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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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The FtsZ-like protein FtsZm of Magnetospirillum gryphiswaldense likely interacts with its generic homolog and is required for biomineralization under nitrate deprivation. J Bacteriol 2013; 196:650-9. [PMID: 24272781 DOI: 10.1128/jb.00804-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Midcell selection, septum formation, and cytokinesis in most bacteria are orchestrated by the eukaryotic tubulin homolog FtsZ. The alphaproteobacterium Magnetospirillum gryphiswaldense (MSR-1) septates asymmetrically, and cytokinesis is linked to splitting and segregation of an intracellular chain of membrane-enveloped magnetite crystals (magnetosomes). In addition to a generic, full-length ftsZ gene, MSR-1 contains a truncated ftsZ homolog (ftsZm) which is located adjacent to genes controlling biomineralization and magnetosome chain formation. We analyzed the role of FtsZm in cell division and biomineralization together with the full-length MSR-1 FtsZ protein. Our results indicate that loss of FtsZm has a strong effect on microoxic magnetite biomineralization which, however, could be rescued by the presence of nitrate in the medium. Fluorescence microscopy revealed that FtsZm-mCherry does not colocalize with the magnetosome-related proteins MamC and MamK but is confined to asymmetric spots at midcell and at the cell pole, coinciding with the FtsZ protein position. In Escherichia coli, both FtsZ homologs form distinct structures but colocalize when coexpressed, suggesting an FtsZ-dependent recruitment of FtsZm. In vitro analyses indicate that FtsZm is able to interact with the FtsZ protein. Together, our data suggest that FtsZm shares key features with its full-length homolog but is involved in redox control for magnetite crystallization.
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15
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Keffer JL, Huecas S, Hammill JT, Wipf P, Andreu JM, Bewley CA. Chrysophaentins are competitive inhibitors of FtsZ and inhibit Z-ring formation in live bacteria. Bioorg Med Chem 2013; 21:5673-8. [PMID: 23932448 PMCID: PMC3768135 DOI: 10.1016/j.bmc.2013.07.033] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 07/06/2013] [Accepted: 07/16/2013] [Indexed: 12/17/2022]
Abstract
The bacterial cell division protein FtsZ polymerizes in a GTP-dependent manner to form a Z-ring that marks the plane of division. As a validated antimicrobial target, considerable efforts have been devoted to identify small molecule FtsZ inhibitors. We recently discovered the chrysophaentins, a novel suite of marine natural products that inhibit FtsZ activity in vitro. These natural products along with a synthetic hemi-chrysophaentin exhibit strong antimicrobial activity toward a broad spectrum of Gram-positive pathogens. To define their mechanisms of FtsZ inhibition and determine their in vivo effects in live bacteria, we used GTPase assays and fluorescence anisotropy to show that hemi-chrysophaentin competitively inhibits FtsZ activity. Furthermore, we developed a model system using a permeable Escherichia coli strain, envA1, together with an inducible FtsZ-yellow fluorescent protein construct to show by fluorescence microscopy that both chrysophaentin A and hemi-chrysophaentin disrupt Z-rings in live bacteria. We tested the E. coli system further by reproducing phenotypes observed for zantrins Z1 and Z3, and demonstrate that the alkaloid berberine, a reported FtsZ inhibitor, exhibits auto-fluorescence, making it incompatible with systems that employ GFP or YFP tagged FtsZ. These studies describe unique examples of nonnucleotide, competitive FtsZ inhibitors that disrupt FtsZ in vivo, together with a model system that should be useful for in vivo testing of FtsZ inhibitor leads that have been identified through in vitro screens but are unable to penetrate the Gram-negative outer membrane.
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Affiliation(s)
- Jessica L. Keffer
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Sonia Huecas
- Centro de Investigaciones Biologicas, CSIC, Madrid, Spain
| | - Jared T. Hammill
- Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Peter Wipf
- Centro de Investigaciones Biologicas, CSIC, Madrid, Spain
| | - Jose M. Andreu
- Centro de Investigaciones Biologicas, CSIC, Madrid, Spain
| | - Carole A. Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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16
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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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17
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Lutkenhaus J, Pichoff S, Du S. Bacterial cytokinesis: From Z ring to divisome. Cytoskeleton (Hoboken) 2012; 69:778-90. [PMID: 22888013 DOI: 10.1002/cm.21054] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 11/07/2022]
Abstract
Ancestral homologues of the major eukaryotic cytoskeletal families, tubulin and actin, play critical roles in cytokinesis of bacterial cells. FtsZ is the ancestral homologue of tubulin and assembles into the Z ring that determines the division plane. FtsA, a member of the actin family, is involved in coordinating cell wall synthesis during cytokinesis. FtsA assists in the formation of the Z ring and also has a critical role in recruiting downstream division proteins to the Z ring to generate the divisome that divides the cell. Spatial regulation of cytokinesis occurs at the stage of Z ring assembly and regulation of cell size occurs at this stage or during Z ring maturation.
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Affiliation(s)
- Joe Lutkenhaus
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas.
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18
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Buske PJ, Levin PA. Extreme C terminus of bacterial cytoskeletal protein FtsZ plays fundamental role in assembly independent of modulatory proteins. J Biol Chem 2012; 287:10945-57. [PMID: 22298780 DOI: 10.1074/jbc.m111.330324] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Bacterial cell division typically requires assembly of the cytoskeletal protein FtsZ into a ring (Z-ring) at the nascent division site that serves as a foundation for assembly of the division apparatus. High resolution imaging suggests that the Z-ring consists of short, single-stranded polymers held together by lateral interactions. Several proteins implicated in stabilizing the Z-ring enhance lateral interactions between FtsZ polymers in vitro. Here we report that residues at the C terminus of Bacillus subtilis FtsZ (C-terminal variable region (CTV)) are both necessary and sufficient for stimulating lateral interactions in vitro in the absence of modulatory proteins. Swapping the 6-residue CTV from B. subtilis FtsZ with the 4-residue CTV from Escherichia coli FtsZ completely abolished lateral interactions between chimeric B. subtilis FtsZ polymers. The E. coli FtsZ chimera readily formed higher order structures normally seen only in the presence of molecular crowding agents. CTV-mediated lateral interactions are important for the integrity of the Z-ring because B. subtilis cells expressing the B. subtilis FtsZ chimera had a low frequency of FtsZ ring formation and a high degree of filamentation relative to wild-type cells. Site-directed mutagenesis of the B. subtilis CTV suggests that electrostatic forces are an important determinant of lateral interaction potential.
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Affiliation(s)
- Paul J Buske
- Department of Biology, Washington University, Saint Louis, Missouri 63130, USA
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19
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Abstract
The bacterial tubulin homologue FtsZ forms a ring-like structure called the Z ring that drives cytokinesis. We showed previously that FtsZ-YFP-mts, which has a short amphipathic helix (mts) on its C terminus that inserts into the membrane, can assemble contractile Z rings in tubular liposomes without any other protein. Here we study mts-FtsZ-YFP, where the membrane tether is switched to the opposite side of the protofilament. This assembled 'inside-out' Z rings that wrapped around the outside surface of tubular liposomes. The inside-out Z rings were highly dynamic, and generated a constriction force that squeezed the tubular liposomes from outside. This is consistent with models where the constriction force is generated by curved protofilaments bending the membrane. We used this system to test how GTP hydrolysis by FtsZ is involved in Z-ring constriction. Without GTP hydrolysis, Z rings could still assemble and generate an initial constriction. However, the constriction quickly stopped, suggesting that Z rings became rigidly stabilized in the absence of GTP hydrolysis. We propose that remodelling of the Z ring, mediated by GTP hydrolysis and exchange of subunits, is necessary for the continuous constriction.
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Affiliation(s)
- Masaki Osawa
- Department of Cell Biology, 3079, Duke University Medical Center, Durham, NC 27710-3709, USA.
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20
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FtsZ in bacterial cytokinesis: cytoskeleton and force generator all in one. Microbiol Mol Biol Rev 2011; 74:504-28. [PMID: 21119015 DOI: 10.1128/mmbr.00021-10] [Citation(s) in RCA: 460] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
FtsZ, a bacterial homolog of tubulin, is well established as forming the cytoskeletal framework for the cytokinetic ring. Recent work has shown that purified FtsZ, in the absence of any other division proteins, can assemble Z rings when incorporated inside tubular liposomes. Moreover, these artificial Z rings can generate a constriction force, demonstrating that FtsZ is its own force generator. Here we review light microscope observations of how Z rings assemble in bacteria. Assembly begins with long-pitch helices that condense into the Z ring. Once formed, the Z ring can transition to short-pitch helices that are suggestive of its structure. FtsZ assembles in vitro into short protofilaments that are ∼30 subunits long. We present models for how these protofilaments might be further assembled into the Z ring. We discuss recent experiments on assembly dynamics of FtsZ in vitro, with particular attention to how two regulatory proteins, SulA and MinC, inhibit assembly. Recent efforts to develop antibacterial drugs that target FtsZ are reviewed. Finally, we discuss evidence of how FtsZ generates a constriction force: by protofilament bending into a curved conformation.
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21
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Yao D, Buchan A, Suzuki MT. In situ activity of NAC11-7 roseobacters in coastal waters off the Chesapeake Bay based on ftsZ expression. Environ Microbiol 2011; 13:1032-41. [DOI: 10.1111/j.1462-2920.2010.02408.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Mingorance J, Rivas G, Vélez M, Gómez-Puertas P, Vicente M. Strong FtsZ is with the force: mechanisms to constrict bacteria. Trends Microbiol 2010; 18:348-56. [PMID: 20598544 DOI: 10.1016/j.tim.2010.06.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 05/10/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022]
Abstract
FtsZ, the best-known prokaryotic division protein, assembles at midcell with other proteins forming a ring during septation. Widely conserved in bacteria, FtsZ represents the ancestor of tubulin. In the presence of GTP it forms polymers able to associate into multi-stranded flexible structures. FtsZ research is aimed at determining the role of the Z-ring in division, describing the polymerization and potential force-generating mechanisms and evaluating the roles of nucleotide exchange and hydrolysis. Systems to reconstruct the FtsZ ring in vitro have been described and some of its mechanical properties have been reproduced using in silico modeling. We discuss current research in FtsZ, some of the controversies, and finally propose further research needed to complete a model of FtsZ action that reconciles its in vitro properties with its role in division.
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Affiliation(s)
- Jesús Mingorance
- Unidad de Investigación y Servicio de Microbiología, Hospital Universitario La Paz (IdiPAZ), Paseo de La Castellana, 261, 28046 Madrid, Spain.
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23
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Abstract
Bacterial cytoskeletal elements are involved in an astonishing spectrum of cellular functions, from cell shape determination to cell division, plasmid segregation, the positioning of membrane-associated proteins and membrane structures, and other aspects of bacterial physiology. Interestingly, these functions are not necessarily conserved, neither between different bacterial species nor between bacteria and eukaryotic cells. The flexibility of cytoskeletal elements in performing different tasks is amazing and emphasises their very early development during evolution. This review focuses on the dynamics of cytoskeletal elements from bacteria.
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Affiliation(s)
- Peter L Graumann
- Mikrobiology, Faculty for Biology, University of Freiburg, Freiburg, Germany.
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24
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Cell division is dispensable but not irrelevant in Streptomyces. Curr Opin Microbiol 2009; 12:689-98. [PMID: 19889570 DOI: 10.1016/j.mib.2009.10.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 10/06/2009] [Accepted: 10/09/2009] [Indexed: 11/21/2022]
Abstract
In part, members of the genus Streptomyces have been studied because they produce many important secondary metabolites with antibiotic activity and for the interest in their relatively elaborate life cycle. These sporulating filamentous bacteria are remarkably synchronous for division and genome segregation in specialized aerial hyphae. Streptomycetes share some, but not all, of the division genes identified in the historic model rod-shaped organisms. Curiously, normally essential cell division genes are dispensable for growth and viability of Streptomyces coelicolor. Mainly, cell division plays a more important role in the developmental phase of life than during vegetative growth. Dispensability provides an advantageous genetic system to probe the mechanisms of division proteins, especially those with functions that are poorly understood.
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25
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Maggi S, Massidda O, Luzi G, Fadda D, Paolozzi L, Ghelardini P. Division protein interaction web: identification of a phylogenetically conserved common interactome between Streptococcus pneumoniae and Escherichia coli. Microbiology (Reading) 2008; 154:3042-3052. [DOI: 10.1099/mic.0.2008/018697-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Silvia Maggi
- Dipartimento di Biologia, Università Tor Vergata, Roma, Italy
| | - Orietta Massidda
- Dipartimento di Scienze e Tecnologie Biomediche, Sez. Microbiologia Medica, Cagliari, Italy
| | - Giuseppe Luzi
- Dipartimento di Medicina Interna, Facoltà di Medicina, Università La Sapienza, Roma, Italy
| | - Daniela Fadda
- Dipartimento di Scienze e Tecnologie Biomediche, Sez. Microbiologia Medica, Cagliari, Italy
| | | | - Patrizia Ghelardini
- Istituto di Biologia e Patologia Molecolare del CNR, Roma, Italy
- Dipartimento di Biologia, Università Tor Vergata, Roma, Italy
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26
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Surovtsev IV, Morgan JJ, Lindahl PA. Kinetic modeling of the assembly, dynamic steady state, and contraction of the FtsZ ring in prokaryotic cytokinesis. PLoS Comput Biol 2008; 4:e1000102. [PMID: 18604268 PMCID: PMC2432035 DOI: 10.1371/journal.pcbi.1000102] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 05/21/2008] [Indexed: 11/19/2022] Open
Abstract
Cytokinesis in prokaryotes involves the assembly of a polymeric ring composed of FtsZ protein monomeric units. The Z ring forms at the division plane and is attached to the membrane. After assembly, it maintains a stable yet dynamic steady state. Once induced, the ring contracts and the membrane constricts. In this work, we present a computational deterministic biochemical model exhibiting this behavior. The model is based on biochemical features of FtsZ known from in vitro studies, and it quantitatively reproduces relevant in vitro data. An essential part of the model is a consideration of interfacial reactions involving the cytosol volume, where monomeric FtsZ is dispersed, and the membrane surface in the cell's mid-zone where the ring is assembled. This approach allows the same chemical model to simulate either in vitro or in vivo conditions by adjusting only two geometrical parameters. The model includes minimal reactions, components, and assumptions, yet is able to reproduce sought-after in vivo behavior, including the rapid assembly of the ring via FtsZ-polymerization, the formation of a dynamic steady state in which GTP hydrolysis leads to the exchange of monomeric subunits between cytoplasm and the ring, and finally the induced contraction of the ring. The model gives a quantitative estimate for coupling between the rate of GTP hydrolysis and of FtsZ subunit turnover between the assembled ring and the cytoplasmic pool as observed. Membrane constriction is chemically driven by the strong tendency of GTP-bound FtsZ to self-assembly. The model suggests a possible mechanism of membrane contraction without a motor protein. The portion of the free energy of GTP hydrolysis released in cyclization is indirectly used in this energetically unfavorable process. The model provides a limit to the mechanistic complexity required to mimic ring behavior, and it highlights the importance of parallel in vitro and in vivo modeling.
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Affiliation(s)
- Ivan V. Surovtsev
- Departments of Chemistry and Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Jeffrey J. Morgan
- Department of Mathematics, University of Houston, Houston, Texas, United States of America
| | - Paul A. Lindahl
- Departments of Chemistry and Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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27
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Dajkovic A, Lan G, Sun SX, Wirtz D, Lutkenhaus J. MinC Spatially Controls Bacterial Cytokinesis by Antagonizing the Scaffolding Function of FtsZ. Curr Biol 2008; 18:235-44. [DOI: 10.1016/j.cub.2008.01.042] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 12/21/2007] [Accepted: 01/04/2008] [Indexed: 10/22/2022]
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28
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Abstract
The eukaryotic cytoskeleton appears to have evolved from ancestral precursors related to prokaryotic FtsZ and MreB. FtsZ and MreB show 40-50% sequence identity across different bacterial and archaeal species. Here I suggest that this represents the limit of divergence that is consistent with maintaining their functions for cytokinesis and cell shape. Previous analyses have noted that tubulin and actin are highly conserved across eukaryotic species, but so divergent from their prokaryotic relatives as to be hardly recognizable from sequence comparisons. One suggestion for this extreme divergence of tubulin and actin is that it occurred as they evolved very different functions from FtsZ and MreB. I will present new arguments favoring this suggestion, and speculate on pathways. Moreover, the extreme conservation of tubulin and actin across eukaryotic species is not due to an intrinsic lack of variability, but is attributed to their acquisition of elaborate mechanisms for assembly dynamics and their interactions with multiple motor and binding proteins. A new structure-based sequence alignment identifies amino acids that are conserved from FtsZ to tubulins. The highly conserved amino acids are not those forming the subunit core or protofilament interface, but those involved in binding and hydrolysis of GTP.
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Affiliation(s)
- Harold P Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710-3709, USA.
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29
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Maple J, Møller SG. Plastid division coordination across a double-membraned structure. FEBS Lett 2007; 581:2162-7. [PMID: 17350001 DOI: 10.1016/j.febslet.2007.02.062] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2006] [Revised: 02/19/2007] [Accepted: 02/26/2007] [Indexed: 11/16/2022]
Abstract
Chloroplasts still retain components of the bacterial cell division machinery and research over the past decade has led to an understanding of how these stromal division proteins assemble and function as a complex chloroplast division machinery. However, during evolution plant chloroplasts have acquired a number of cytosolic division proteins, indicating that unlike the cyanobacterial ancestors of plastids, chloroplast division in higher plants require a second division machinery located on the chloroplast outer envelope membrane. Here we review the current understanding of the stromal and cytosolic plastid division machineries and speculate how two protein machineries coordinate their activities across a double-membraned structure.
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Affiliation(s)
- Jodi Maple
- Centre for Organelle Research, Department of Mathematics and Natural Sciences, University of Stavanger, N-4036 Stavanger, Norway
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