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Cameron TA, Margolin W. Insights into the assembly and regulation of the bacterial divisome. Nat Rev Microbiol 2024; 22:33-45. [PMID: 37524757 PMCID: PMC11102604 DOI: 10.1038/s41579-023-00942-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2023] [Indexed: 08/02/2023]
Abstract
The ability to split one cell into two is fundamental to all life, and many bacteria can accomplish this feat several times per hour with high accuracy. Most bacteria call on an ancient homologue of tubulin, called FtsZ, to localize and organize the cell division machinery, the divisome, into a ring-like structure at the cell midpoint. The divisome includes numerous other proteins, often including an actin homologue (FtsA), that interact with each other at the cytoplasmic membrane. Once assembled, the protein complexes that comprise the dynamic divisome coordinate membrane constriction with synthesis of a division septum, but only after overcoming checkpoints mediated by specialized protein-protein interactions. In this Review, we summarize the most recent evidence showing how the divisome proteins of Escherichia coli assemble at the cell midpoint, interact with each other and regulate activation of septum synthesis. We also briefly discuss the potential of divisome proteins as novel antibiotic targets.
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Affiliation(s)
- Todd A Cameron
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX, USA
| | - William Margolin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, Houston, TX, USA.
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2
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Ramm B, Heermann T, Schwille P. The E. coli MinCDE system in the regulation of protein patterns and gradients. Cell Mol Life Sci 2019; 76:4245-4273. [PMID: 31317204 PMCID: PMC6803595 DOI: 10.1007/s00018-019-03218-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/27/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022]
Abstract
Molecular self-organziation, also regarded as pattern formation, is crucial for the correct distribution of cellular content. The processes leading to spatiotemporal patterns often involve a multitude of molecules interacting in complex networks, so that only very few cellular pattern-forming systems can be regarded as well understood. Due to its compositional simplicity, the Escherichia coli MinCDE system has, thus, become a paradigm for protein pattern formation. This biological reaction diffusion system spatiotemporally positions the division machinery in E. coli and is closely related to ParA-type ATPases involved in most aspects of spatiotemporal organization in bacteria. The ATPase MinD and the ATPase-activating protein MinE self-organize on the membrane as a reaction matrix. In vivo, these two proteins typically oscillate from pole-to-pole, while in vitro they can form a variety of distinct patterns. MinC is a passenger protein supposedly operating as a downstream cue of the system, coupling it to the division machinery. The MinCDE system has helped to extract not only the principles underlying intracellular patterns, but also how they are shaped by cellular boundaries. Moreover, it serves as a model to investigate how patterns can confer information through specific and non-specific interactions with other molecules. Here, we review how the three Min proteins self-organize to form patterns, their response to geometric boundaries, and how these patterns can in turn induce patterns of other molecules, focusing primarily on experimental approaches and developments.
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Affiliation(s)
- Beatrice Ramm
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Tamara Heermann
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
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3
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The Bacterial DNA Binding Protein MatP Involved in Linking the Nucleoid Terminal Domain to the Divisome at Midcell Interacts with Lipid Membranes. mBio 2019; 10:mBio.00376-19. [PMID: 31138739 PMCID: PMC6538776 DOI: 10.1128/mbio.00376-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The division of an E. coli cell into two daughter cells with equal genomic information and similar size requires duplication and segregation of the chromosome and subsequent scission of the envelope by a protein ring, the Z-ring. MatP is a DNA binding protein that contributes both to the positioning of the Z-ring at midcell and the temporal control of nucleoid segregation. Our integrated in vivo and in vitro analysis provides evidence that MatP can interact with lipid membranes reproducing the phospholipid mixture in the E. coli inner membrane, without concomitant recruitment of the short DNA sequences specifically targeted by MatP. This observation strongly suggests that the membrane may play a role in the regulation of the function and localization of MatP, which could be relevant for the coordination of the two fundamental processes in which this protein participates, nucleoid segregation and cell division. Division ring formation at midcell is controlled by various mechanisms in Escherichia coli, one of them being the linkage between the chromosomal Ter macrodomain and the Z-ring mediated by MatP, a DNA binding protein that organizes this macrodomain and contributes to the prevention of premature chromosome segregation. Here we show that, during cell division, just before splitting the daughter cells, MatP seems to localize close to the cytoplasmic membrane, suggesting that this protein might interact with lipids. To test this hypothesis, we investigated MatP interaction with lipids in vitro. We found that, when encapsulated inside vesicles and microdroplets generated by microfluidics, MatP accumulates at phospholipid bilayers and monolayers matching the lipid composition in the E. coli inner membrane. MatP binding to lipids was independently confirmed using lipid-coated microbeads and biolayer interferometry assays, which suggested that the recognition is mainly hydrophobic. Interaction of MatP with the lipid membranes also occurs in the presence of the DNA sequences specifically targeted by the protein, but there is no evidence of ternary membrane/protein/DNA complexes. We propose that the association of MatP with lipids may modulate its spatiotemporal localization and its recognition of other ligands.
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4
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Wettmann L, Kruse K. The Min-protein oscillations in Escherichia coli: an example of self-organized cellular protein waves. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0111. [PMID: 29632263 DOI: 10.1098/rstb.2017.0111] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2017] [Indexed: 01/09/2023] Open
Abstract
In the rod-shaped bacterium Escherichia coli, selection of the cell centre as the division site involves pole-to-pole oscillations of the proteins MinC, MinD and MinE. This spatio-temporal pattern emerges from interactions among the Min proteins and with the cytoplasmic membrane. Combining experimental studies in vivo and in vitro together with theoretical analysis has led to a fairly good understanding of Min-protein self-organization. In different geometries, the system can, in addition to standing waves, also produce travelling planar and spiral waves as well as coexisting stable stationary distributions. Today it stands as one of the best-studied examples of cellular self-organization of proteins.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Lukas Wettmann
- Theoretische Physik, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany
| | - Karsten Kruse
- Departments of Biochemistry and Theoretical Physics, NCCR Chemical Biology, University of Geneva, 1211 Geneva, Switzerland
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5
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Yang Y, Wu M. Rhythmicity and waves in the cortex of single cells. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0116. [PMID: 29632268 PMCID: PMC5904302 DOI: 10.1098/rstb.2017.0116] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/30/2017] [Indexed: 12/15/2022] Open
Abstract
Emergence of dynamic patterns in the form of oscillations and waves on the cortex of single cells is a fascinating and enigmatic phenomenon. Here we outline various theoretical frameworks used to model pattern formation with the goal of reducing complex, heterogeneous patterns into key parameters that are biologically tractable. We also review progress made in recent years on the quantitative and molecular definitions of these terms, which we believe have begun to transform single-cell dynamic patterns from a purely observational and descriptive subject to more mechanistic studies. Specifically, we focus on the nature of local excitable and oscillation events, their spatial couplings leading to propagating waves and the role of active membrane. Instead of arguing for their functional importance, we prefer to consider such patterns as basic properties of dynamic systems. We discuss how knowledge of these patterns could be used to dissect the structure of cellular organization and how the network-centric view could help define cellular functions as transitions between different dynamical states. Last, we speculate on how these patterns could encode temporal and spatial information. This article is part of the theme issue ‘Self-organization in cell biology’.
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Affiliation(s)
- Yang Yang
- Department of Biological Sciences, Centre for Bioimaging Sciences, Mechanobiology Institute, National University of Singapore, Singapore
| | - Min Wu
- Department of Biological Sciences, Centre for Bioimaging Sciences, Mechanobiology Institute, National University of Singapore, Singapore
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6
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Walsh JC, Angstmann CN, Duggin IG, Curmi PMG. Non-linear Min protein interactions generate harmonics that signal mid-cell division in Escherichia coli. PLoS One 2017; 12:e0185947. [PMID: 29040283 PMCID: PMC5645087 DOI: 10.1371/journal.pone.0185947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/21/2017] [Indexed: 11/18/2022] Open
Abstract
The Min protein system creates a dynamic spatial pattern in Escherichia coli cells where the proteins MinD and MinE oscillate from pole to pole. MinD positions MinC, an inhibitor of FtsZ ring formation, contributing to the mid-cell localization of cell division. In this paper, Fourier analysis is used to decompose experimental and model MinD spatial distributions into time-dependent harmonic components. In both experiment and model, the second harmonic component is responsible for producing a mid-cell minimum in MinD concentration. The features of this harmonic are robust in both experiment and model. Fourier analysis reveals a close correspondence between the time-dependent behaviour of the harmonic components in the experimental data and model. Given this, each molecular species in the model was analysed individually. This analysis revealed that membrane-bound MinD dimer shows the mid-cell minimum with the highest contrast when averaged over time, carrying the strongest signal for positioning the cell division ring. This concurs with previous data showing that the MinD dimer binds to MinC inhibiting FtsZ ring formation. These results show that non-linear interactions of Min proteins are essential for producing the mid-cell positioning signal via the generation of second-order harmonic components in the time-dependent spatial protein distribution.
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Affiliation(s)
- James C. Walsh
- School of Physics, University of New South Wales, Sydney, NSW, Australia
- The Ithree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | | | - Iain G. Duggin
- The Ithree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Paul M. G. Curmi
- School of Physics, University of New South Wales, Sydney, NSW, Australia
- * E-mail:
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7
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MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers. Biochem J 2017; 474:3189-3205. [PMID: 28743721 DOI: 10.1042/bcj20170357] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/10/2017] [Accepted: 07/25/2017] [Indexed: 12/30/2022]
Abstract
Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC-FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD-FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.
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8
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MacCready JS, Schossau J, Osteryoung KW, Ducat DC. Robust Min-system oscillation in the presence of internal photosynthetic membranes in cyanobacteria. Mol Microbiol 2016; 103:483-503. [PMID: 27891682 DOI: 10.1111/mmi.13571] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2016] [Indexed: 11/29/2022]
Abstract
The oscillatory Min system of Escherichia coli defines the cell division plane by regulating the site of FtsZ-ring formation and represents one of the best-understood examples of emergent protein self-organization in nature. The oscillatory patterns of the Min-system proteins MinC, MinD and MinE (MinCDE) are strongly dependent on the geometry of membranes they bind. Complex internal membranes within cyanobacteria could disrupt this self-organization by sterically occluding or sequestering MinCDE from the plasma membrane. Here, it was shown that the Min system in the cyanobacterium Synechococcus elongatus PCC 7942 oscillates from pole-to-pole despite the potential spatial constraints imposed by their extensive thylakoid network. Moreover, reaction-diffusion simulations predict robust oscillations in modeled cyanobacterial cells provided that thylakoid network permeability is maintained to facilitate diffusion, and suggest that Min proteins require preferential affinity for the plasma membrane over thylakoids to correctly position the FtsZ ring. Interestingly, in addition to oscillating, MinC exhibits a midcell localization dependent on MinD and the DivIVA-like protein Cdv3, indicating that two distinct pools of MinC are coordinated in S. elongatus. Our results provide the first direct evidence for Min oscillation outside of E. coli and have broader implications for Min-system function in bacteria and organelles with internal membrane systems.
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Affiliation(s)
- Joshua S MacCready
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Jory Schossau
- Department of Computer Science, Michigan State University, East Lansing, MI, 48824, USA
| | | | - Daniel C Ducat
- Department of Biochemistry, MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
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9
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Abstract
With the realization that bacteria achieve exquisite levels of spatiotemporal organization has come the challenge of discovering the underlying mechanisms. In this review, we describe three classes of such mechanisms, each of which has physical origins: the use of landmarks, the creation of higher-order structures that enable geometric sensing, and the emergence of length scales from systems of chemical reactions coupled to diffusion. We then examine the diversity of geometric cues that exist even in cells with relatively simple geometries, and end by discussing both new technologies that could drive further discovery and the implications of our current knowledge for the behavior, fitness, and evolution of bacteria. The organizational strategies described here are employed in a wide variety of systems and in species across all kingdoms of life; in many ways they provide a general blueprint for organizing the building blocks of life.
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Affiliation(s)
- Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544;
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10
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Nishida Y, Takeuchi H, Morimoto N, Umeda A, Kadota Y, Kira M, Okazaki A, Matsumura Y, Sugiura T. Intrinsic characteristics of Min proteins on the cell division of Helicobacter pylori. FEMS Microbiol Lett 2016; 363:fnw025. [PMID: 26862143 DOI: 10.1093/femsle/fnw025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2016] [Indexed: 01/24/2023] Open
Abstract
Helicobacter pylori divides in the human stomach resulting in persistent infections and causing various disorders. Bacterial cell division is precisely coordinated by many molecules, including FtsZ and Min proteins. However, the role of Min proteins in H. pylori division is poorly understood. We investigated the functional characteristics of Min proteins in wild-type HPK5 and five HPK5-derivative mutants using morphological and genetic approaches. All mutants showed a filamentous shape. However, the bacterial cell growth and viability of three single-gene mutants (minC, minD, minE) were similar to that of the wild-type. The coccoid form number was lowest in the minE-disruptant, indicating that MinE contributes to the coccoid form conversion during the stationary phase. Immunofluorescence microscopic observations showed that FtsZ was dispersedly distributed throughout the bacterial cell irrespective of nucleoid position in only minD-disruptants, indicating that MinD is involved in the nucleoid occlusion system. A chase assay demonstrated that MinC loss suppressed FtsZ-degradation, indicating that FtsZ degrades in a MinC-dependent manner. Molecular interactions between FtsZ and Min proteins were confirmed by immunoprecipitation (IP)-western blotting (WB), suggesting the functional cooperation of these molecules during bacterial cell division. This study describes the intrinsic characteristics of Min proteins and provides new insights into H. pylori cell division.
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Affiliation(s)
- Yoshie Nishida
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Hiroaki Takeuchi
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Norihito Morimoto
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Akiko Umeda
- Department of Clinical Laboratory Medicine, Yamaguchi University, 1-1-1 MinamiKogushi, Ube-city, Yamaguchi 755-8505, Japan
| | - Yoshu Kadota
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Mizuki Kira
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Ami Okazaki
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Yoshihisa Matsumura
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
| | - Tetsuro Sugiura
- Department of Clinical Laboratory Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku-city, Kochi 783-8505, Japan
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11
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Abstract
It is pointed out that the mystery of how biological systems measure their lengths vanishes away if one premises that they have discovered a way to generate linear waves analogous to compressional sound. These can be used to detect length at either large or small scales using echo timing and fringe counting. It is shown that suitable linear chemical potential waves can, in fact, be manufactured by tuning to criticality conventional reaction-diffusion with a small number substance. Min oscillations in Escherichia coli are cited as precedent resonant length measurement using chemical potential waves analogous to laser detection. Mitotic structures in eukaryotes are identified as candidates for such an effect at higher frequency. The engineering principle is shown to be very general and functionally the same as that used by hearing organs.
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12
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Vischer NOE, Verheul J, Postma M, van den Berg van Saparoea B, Galli E, Natale P, Gerdes K, Luirink J, Vollmer W, Vicente M, den Blaauwen T. Cell age dependent concentration of Escherichia coli divisome proteins analyzed with ImageJ and ObjectJ. Front Microbiol 2015; 6:586. [PMID: 26124755 PMCID: PMC4462998 DOI: 10.3389/fmicb.2015.00586] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/28/2015] [Indexed: 11/28/2022] Open
Abstract
The rod-shaped Gram-negative bacterium Escherichia coli multiplies by elongation followed by binary fission. Longitudinal growth of the cell envelope and synthesis of the new poles are organized by two protein complexes called elongasome and divisome, respectively. We have analyzed the spatio-temporal localization patterns of many of these morphogenetic proteins by immunolabeling the wild type strain MC4100 grown to steady state in minimal glucose medium at 28°C. This allowed the direct comparison of morphogenetic protein localization patterns as a function of cell age as imaged by phase contrast and fluorescence wide field microscopy. Under steady state conditions the age distribution of the cells is constant and is directly correlated to cell length. To quantify cell size and protein localization parameters in 1000s of labeled cells, we developed ‘Coli-Inspector,’ which is a project running under ImageJ with the plugin ‘ObjectJ.’ ObjectJ organizes image-analysis tasks using an integrated approach with the flexibility to produce different output formats from existing markers such as intensity data and geometrical parameters. ObjectJ supports the combination of automatic and interactive methods giving the user complete control over the method of image analysis and data collection, with visual inspection tools for quick elimination of artifacts. Coli-inspector was used to sort the cells according to division cycle cell age and to analyze the spatio-temporal localization pattern of each protein. A unique dataset has been created on the concentration and position of the proteins during the cell cycle. We show for the first time that a subset of morphogenetic proteins have a constant cellular concentration during the cell division cycle whereas another set exhibits a cell division cycle dependent concentration variation. Using the number of proteins present at midcell, the stoichiometry of the divisome is discussed.
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Affiliation(s)
- Norbert O E Vischer
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, Netherlands
| | - Jolanda Verheul
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, Netherlands
| | - Marten Postma
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, Netherlands ; Molecular Cytology, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam Amsterdam, Netherlands
| | - Bart van den Berg van Saparoea
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, Netherlands ; Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University Amsterdam, Netherlands
| | - Elisa Galli
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK
| | - Paolo Natale
- Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Kenn Gerdes
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK ; Department of Biology, University of Copenhagen Copenhagen, Denmark
| | - Joen Luirink
- Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University Amsterdam, Netherlands
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK
| | - Miguel Vicente
- Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Tanneke den Blaauwen
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam Amsterdam, Netherlands
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13
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Walsh JC, Angstmann CN, Duggin IG, Curmi PMG. Molecular Interactions of the Min Protein System Reproduce Spatiotemporal Patterning in Growing and Dividing Escherichia coli Cells. PLoS One 2015; 10:e0128148. [PMID: 26018614 PMCID: PMC4446092 DOI: 10.1371/journal.pone.0128148] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/22/2015] [Indexed: 11/24/2022] Open
Abstract
Oscillations of the Min protein system are involved in the correct midcell placement of the divisome during Escherichia coli cell division. Based on molecular interactions of the Min system, we formulated a mathematical model that reproduces Min patterning during cell growth and division. Specifically, the increase in the residence time of MinD attached to the membrane as its own concentration increases, is accounted for by dimerisation of membrane-bound MinD and its interaction with MinE. Simulation of this system generates unparalleled correlation between the waveshape of experimental and theoretical MinD distributions, suggesting that the dominant interactions of the physical system have been successfully incorporated into the model. For cells where MinD is fully-labelled with GFP, the model reproduces the stationary localization of MinD-GFP for short cells, followed by oscillations from pole to pole in larger cells, and the transition to the symmetric distribution during cell filamentation. Cells containing a secondary, GFP-labelled MinD display a contrasting pattern. The model is able to account for these differences, including temporary midcell localization just prior to division, by increasing the rate constant controlling MinD ATPase and heterotetramer dissociation. For both experimental conditions, the model can explain how cell division results in an equal distribution of MinD and MinE in the two daughter cells, and accounts for the temperature dependence of the period of Min oscillations. Thus, we show that while other interactions may be present, they are not needed to reproduce the main characteristics of the Min system in vivo.
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Affiliation(s)
- James C. Walsh
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
- The ithree institute, University of Technology, Sydney NSW 2007, Australia
| | | | - Iain G. Duggin
- The ithree institute, University of Technology, Sydney NSW 2007, Australia
| | - Paul M. G. Curmi
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
- * E-mail:
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14
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Rowlett VW, Margolin W. The Min system and other nucleoid-independent regulators of Z ring positioning. Front Microbiol 2015; 6:478. [PMID: 26029202 PMCID: PMC4429545 DOI: 10.3389/fmicb.2015.00478] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/30/2015] [Indexed: 11/13/2022] Open
Abstract
Rod-shaped bacteria such as E. coli have mechanisms to position their cell division plane at the precise center of the cell, to ensure that the daughter cells are equal in size. The two main mechanisms are the Min system and nucleoid occlusion (NO), both of which work by inhibiting assembly of FtsZ, the tubulin-like scaffold that forms the cytokinetic Z ring. Whereas NO prevents Z rings from constricting over unsegregated nucleoids, the Min system is nucleoid-independent and even functions in cells lacking nucleoids and thus NO. The Min proteins of E. coli and B. subtilis form bipolar gradients that inhibit Z ring formation most at the cell poles and least at the nascent division plane. This article will outline the molecular mechanisms behind Min function in E. coli and B. subtilis, and discuss distinct Z ring positioning systems in other bacterial species.
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Affiliation(s)
- Veronica W Rowlett
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston , Houston, TX, USA
| | - William Margolin
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston , Houston, TX, USA
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15
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Abstract
A mother cell giving rise to offspring usually needs to choose the site of cytokinesis carefully, as this will determine the size and shape of the daughter cells. Rod-shaped bacteria that divide by binary fission, such as Escherichia coli, often mark their cell division sites at their cell midpoint so that daughter cells are roughly equivalent in size and shape. So how does E. coli know where its middle is? Its cell poles are defined by the previous cell division, but, because E. coli grows by incorporating new cell wall and membrane uniformly along its length, the future cell division site at mid-cell is newly made and has no known pre-existing markers. One way to select the new mid-cell site would be to measure the distance from the two opposing cell poles, using a system that could recognize markers at those poles and define the spot furthest from both markers. This would require that both polar markers act negatively on cell division at equivalent intensities. The result would be a concentration gradient, with the lowest concentration of the negative regulator at the cell midpoint, the greatest distance from both cell poles. It turns out that E. coli and some other rod-shaped bacteria select their cell midpoint using such a negatively acting morphogen gradient, set up by the Min system, which is the focus of this Primer. As is true for many fascinating molecular mechanisms, the first inkling came from the behavior of cells in which this system was broken.
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Affiliation(s)
- Veronica Wells Rowlett
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
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16
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MinC, MinD, and MinE drive counter-oscillation of early-cell-division proteins prior to Escherichia coli septum formation. mBio 2013; 4:e00856-13. [PMID: 24327341 PMCID: PMC3870257 DOI: 10.1128/mbio.00856-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Bacterial cell division initiates with the formation of a ring-like structure at the cell center composed of the tubulin homolog FtsZ (the Z-ring), which acts as a scaffold for the assembly of the cell division complex, the divisome. Previous studies have suggested that the divisome is initially composed of FtsZ polymers stabilized by membrane anchors FtsA and ZipA, which then recruit the remaining division proteins. The MinCDE proteins prevent the formation of the Z-ring at poles by oscillating from pole to pole, thereby ensuring that the concentration of the Z-ring inhibitor, MinC, is lowest at the cell center. We show that prior to septum formation, the early-division proteins ZipA, ZapA, and ZapB, along with FtsZ, assemble into complexes that counter-oscillate with respect to MinC, and with the same period. We propose that FtsZ molecules distal from high concentrations of MinC form relatively slowly diffusing filaments that are bound by ZapAB and targeted to the inner membrane by ZipA or FtsA. These complexes may facilitate the early stages of divisome assembly at midcell. As MinC oscillates toward these complexes, FtsZ oligomerization and bundling are inhibited, leading to shorter or monomeric FtsZ complexes, which become less visible by epifluorescence microscopy because of their rapid diffusion. Reconstitution of FtsZ-Min waves on lipid bilayers shows that FtsZ bundles partition away from high concentrations of MinC and that ZapA appears to protect FtsZ from MinC by inhibiting FtsZ turnover. A big issue in biology for the past 100 years has been that of how a cell finds its middle. In Escherichia coli, over 20 proteins assemble at the cell center at the time of division. We show that the MinCDE proteins, which prevent the formation of septa at the cell pole by inhibiting FtsZ, drive the counter-oscillation of early-cell-division proteins ZapA, ZapB, and ZipA, along with FtsZ. We propose that FtsZ forms filaments at the pole where the MinC concentration is the lowest and acts as a scaffold for binding of ZapA, ZapB, and ZipA: such complexes are disassembled by MinC and reform within the MinC oscillation period before accumulating at the cell center at the time of division. The ability of FtsZ to be targeted to the cell center in the form of oligomers bound by ZipA and ZapAB may facilitate the early stages of divisome assembly.
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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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Jamroškovič J, Pavlendová N, Muchová K, Wilkinson AJ, Barák I. An oscillating Min system in Bacillus subtilis influences asymmetrical septation during sporulation. MICROBIOLOGY-SGM 2012; 158:1972-1981. [PMID: 22628484 PMCID: PMC3542138 DOI: 10.1099/mic.0.059295-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Min system plays an important role in ensuring that cell division occurs at mid-cell in rod-shaped bacteria. In Escherichia coli, pole-to-pole oscillation of the Min proteins specifically inhibits polar septation. This system also prevents polar division in Bacillus subtilis during vegetative growth; however, the Min proteins do not oscillate in this organism. The Min system of B. subtilis plays a distinct role during sporulation, a process of differentiation which begins with an asymmetrical cell division. Here, we show that oscillation of the E. coli Min proteins can be reproduced following their introduction into B. subtilis cells. Further, we present evidence that the oscillatory behaviour of the Min system inhibits sporulation. We propose that an alternative Min system mechanism avoiding oscillation is evolutionarily important because oscillation of the Min system is incompatible with efficient asymmetrical septum formation and sporulation.
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Affiliation(s)
- Ján Jamroškovič
- Institute of Molecular Biology, Slovak Academy of Sciences Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Nad'a Pavlendová
- Institute of Molecular Biology, Slovak Academy of Sciences Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Katarína Muchová
- Institute of Molecular Biology, Slovak Academy of Sciences Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Anthony J Wilkinson
- Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, UK
| | - Imrich Barák
- Institute of Molecular Biology, Slovak Academy of Sciences Dúbravská cesta 21, 845 51 Bratislava, Slovakia
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Cellular architecture mediates DivIVA ultrastructure and regulates min activity in Bacillus subtilis. mBio 2011; 2:mBio.00257-11. [PMID: 22108385 PMCID: PMC3225972 DOI: 10.1128/mbio.00257-11] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
UNLABELLED The assembly of the cell division machinery at midcell is a critical step of cytokinesis. Many rod-shaped bacteria position septa using nucleoid occlusion, which prevents division over the chromosome, and the Min system, which prevents division near the poles. Here we examined the in vivo assembly of the Bacillus subtilis MinCD targeting proteins DivIVA, a peripheral membrane protein that preferentially localizes to negatively curved membranes and resembles eukaryotic tropomyosins, and MinJ, which recruits MinCD to DivIVA. We used structured illumination microscopy to demonstrate that both DivIVA and MinJ localize as double rings that flank the septum and first appear early in septal biosynthesis. The subsequent recruitment of MinCD to these double rings would separate the Min proteins from their target, FtsZ, spatially regulating Min activity and allowing continued cell division. Curvature-based localization would also provide temporal regulation, since DivIVA and the Min proteins would localize to midcell after the onset of division. We use time-lapse microscopy and fluorescence recovery after photobleaching to demonstrate that DivIVA rings are highly stable and are constructed from newly synthesized DivIVA molecules. After cell division, DivIVA rings appear to collapse into patches at the rounded cell poles of separated cells, with little or no incorporation of newly synthesized subunits. Thus, changes in cell architecture mediate both the initial recruitment of DivIVA to sites of cell division and the subsequent collapse of these rings into patches (or rings of smaller diameter), while curvature-based localization of DivIVA spatially and temporally regulates Min activity. IMPORTANCE The Min systems of Escherichia coli and Bacillus subtilis both inhibit FtsZ assembly, but one key difference between these two species is that whereas the E. coli Min proteins localize to the poles, the B. subtilis proteins localize to nascent division sites by interaction with DivIVA and MinJ. It is unclear how MinC activity at midcell is regulated to prevent it from interfering with FtsZ engaged in medial cell division. We used superresolution microscopy to demonstrate that DivIVA and MinJ, which localize MinCD, assemble double rings that flank active division sites and septa. This curvature-based localization mechanism holds MinCD away from the FtsZ ring at midcell, and we propose that this spatial organization is the primary mechanism by which MinC activity is regulated to allow division at midcell. Curvature-based localization also conveys temporal regulation, since it ensures that MinC localizes after the onset of division.
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Abstract
One of the most fundamental features of biological systems is probably their ability to self-organize in space and time on different scales. Despite many elaborate theoretical models of how molecular self-organization can come about, only a few experimental systems of biological origin have so far been rigorously described, due mostly to their inherent complexity. The most promising strategy of modern biophysics is thus to identify minimal biological systems showing self-organized emergent behavior. One of the best-understood examples of protein self-organization, which has recently been successfully reconstituted in vitro, is represented by the oscillations of the Min proteins in Escherichia coli. In this review, we summarize the current understanding of the mechanism of Min protein self-organization in vivo and in vitro. We discuss the potential of the Min oscillations to sense the geometry of the cell and suggest that spontaneous protein waves could be a general means of intracellular organization. We hypothesize that cooperative membrane binding and unbinding, e.g., as an energy-dependent switch, may act as an important regulatory mechanism for protein oscillations and pattern formation in the cell.
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Affiliation(s)
- Martin Loose
- Biophysics, BIOTEC, Dresden University of Technology, Dresden, Germany.
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Abstract
Many RNAs, proteins, and organelles are present in such low numbers per cell that random segregation of individual copies causes large "partitioning errors" at cell division. Even symmetrically dividing cells can then by chance produce daughters with very different composition. The size of the errors depends on the segregation mechanism: Control systems can reduce low-abundance errors, but the segregation process can also be subject to upstream sources of randomness or spatial heterogeneities that create large errors despite high abundances. Here we mathematically demonstrate how partitioning errors arise for different types of segregation mechanisms and how errors can be greatly increased by upstream heterogeneity but remarkably hard to avoid through controlled partitioning. We also show that seemingly straightforward experiments cannot be straightforwardly interpreted because very different mechanisms produce identical fits and present an approach to deal with this problem by adding binomial counting noise and testing for convexity or concavity in the partitioning error as a function of the binomial thinning parameter. The results lay a conceptual groundwork for more effective studies of heterogeneity among growing and dividing cells, whether in microbes or in differentiating tissues.
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Affiliation(s)
- Dann Huh
- Department of Systems Biology, Harvard University, Boston, MA 02115; and
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Johan Paulsson
- Department of Systems Biology, Harvard University, Boston, MA 02115; and
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Di Ventura B, Sourjik V. Self-organized partitioning of dynamically localized proteins in bacterial cell division. Mol Syst Biol 2011; 7:457. [PMID: 21206490 PMCID: PMC3049411 DOI: 10.1038/msb.2010.111] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 11/29/2010] [Indexed: 11/29/2022] Open
Abstract
The Min proteins are equally partitioned between daughter cells at division. The mechanism allowing this accurate distribution is intrinsic to the Min system. Individual oscillations appear in each daughter cell before cytokinesis is completed. Diffusion through the gradually constricting septum is key to this process.
One of the central problems of cell division is the proper distribution of all components to the progeny, which is essential to avoid the adverse effects that an unequal distribution—when not actively sought for differentiation purposes—would have on cell growth and regulation. Fast-growing bacterial cells are particularly exposed to this problem, as corrections of inequalities in protein distribution by biosynthesis could be too slow compared with the generation time. Moreover, bacterial proteins are usually stable and, therefore, their levels are not easily adjustable in one generation. Although for homogeneously distributed proteins an equal partitioning at division is readily achieved, dedicated mechanisms must exist to segregate proteins or cellular structures that possess a specific cellular location, but these mechanisms are largely unknown. An extremely challenging case is represented by the Min proteins—MinC, MinD and MinE—that in Escherichia coli oscillate from pole to pole to inhibit the assembly of the cytokinetic ring anywhere except at mid-cell. The oscillations stem solely from local interactions among the proteins at the cytoplasmic membrane. In this work, we show that self-organization is also responsible for the distribution of Min proteins between daughter cells at division. Our combined experimental and computational results demonstrate that the equal protein partitioning stems from interplay between the self-organized oscillations and changes in the cell geometry during division, with no need for any additional regulatory network. Using high-resolution time-lapse microscopy, we detected changes in the Min oscillatory regime that correlate with the amount of septal constriction (Figure 3A, B, E and F). When the cell is unconstricted, oscillations run from pole to pole (Figure 3A). When the constriction reaches a certain degree, typically corresponding to a septum of 600–500 nm, the oscillations change into a ‘half-cell to half-cell' mode during which the fluorescence covers, alternatively, the entire membrane of one daughter cell (Figure 3A, B and E). This mode persists for several minutes and, just before cell division when the septum is smaller than 200 nm, gives way to yet another oscillatory pattern wherein oscillations split and run independently in each daughter cell (Figure 3A, B and F). Our 3D stochastic computer simulations revealed that these different regimes are an outcome of impaired diffusion through the closing septum and that oscillations finally split because protein exchange between the two future daughter cells becomes critically slow, so that independent oscillations on both sides of the septum become the stable solution (Figure 6A and E). FRAP experiments confirmed that the presence of the septum is enough to slow down the passage of molecules from one side of the cell to the other (Figure 6F). As oscillations become independent in each daughter cell before completion of cytokinesis, diffusion through the septum can still occur, which further equilibrates the levels of the Min proteins in the daughter cells (Figure 3C and D and Figure 6B, C and D). In summary, our results suggest that E. coli cells have evolved a very simple and elegant way to ensure equal concentrations of the Min proteins in the progeny, based entirely on the intrinsic self-organizing properties of the Min system. This provides a clear example of self-organizing partitioning, which we expect to be a widely used strategy given its simplicity and low evolutionary cost. How cells manage to get equal distribution of their structures and molecules at cell division is a crucial issue in biology. In principle, a feedback mechanism could always ensure equality by measuring and correcting the distribution in the progeny. However, an elegant alternative could be a mechanism relying on self-organization, with the interplay between system properties and cell geometry leading to the emergence of equal partitioning. The problem is exemplified by the bacterial Min system that defines the division site by oscillating from pole to pole. Unequal partitioning of Min proteins at division could negatively impact system performance and cell growth because of loss of Min oscillations and imprecise mid-cell determination. In this study, we combine live cell and computational analyses to show that known properties of the Min system together with the gradual reduction of protein exchange through the constricting septum are sufficient to explain the observed highly precise spontaneous protein partitioning. Our findings reveal a novel and effective mechanism of protein partitioning in dividing cells and emphasize the importance of self-organization in basic cellular processes.
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Affiliation(s)
- Barbara Di Ventura
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany.
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Differences in MinC/MinD sensitivity between polar and internal Z rings in Escherichia coli. J Bacteriol 2010; 193:367-76. [PMID: 21097625 DOI: 10.1128/jb.01095-10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In Escherichia coli the Z ring has the potential to assemble anywhere along the cell length but is restricted to midcell by the action of negative regulatory systems, including Min. In the current model for the Min system, the MinC/MinD division inhibitory complex is evenly distributed on the membrane and can disrupt Z rings anywhere in the cell; however, MinE spatially regulates MinC/MinD by restricting it to the cell poles, thus allowing Z ring formation at midcell. This model assumes that Z rings formed at different cellular locations have equal sensitivity to MinC/MinD in the absence of MinE. However, here we report evidence that differences in MinC/MinD sensitivity between polar and nonpolar Z rings exists even when there is no MinE. MinC/MinD at proper levels is able to block minicell production in Δmin strains without increasing the cell length, indicating that polar Z rings are preferentially blocked. In the FtsZ-I374V strain (which is resistant to MinC(C)/MinD), wild-type morphology can be easily achieved with MinC/MinD in the absence of MinE. We also show that MinC/MinD at proper levels can rescue the lethal phenotype of a min slmA double deletion mutant, which we think is due to the elimination of polar Z rings (or FtsZ structures), which frees up FtsZ molecules for assembly of Z rings at internal sites to rescue division and growth. Taken together, these data indicate that polar Z rings are more susceptible to MinC/MinD than internal Z rings, even when MinE is absent.
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