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Radler P, Loose M. A dynamic duo: Understanding the roles of FtsZ and FtsA for Escherichia coli cell division through in vitro approaches. Eur J Cell Biol 2024; 103:151380. [PMID: 38218128 DOI: 10.1016/j.ejcb.2023.151380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/22/2023] [Accepted: 12/24/2023] [Indexed: 01/15/2024] Open
Abstract
Bacteria divide by binary fission. The protein machine responsible for this process is the divisome, a transient assembly of more than 30 proteins in and on the surface of the cytoplasmic membrane. Together, they constrict the cell envelope and remodel the peptidoglycan layer to eventually split the cell into two. For Escherichia coli, most molecular players involved in this process have probably been identified, but obtaining the quantitative information needed for a mechanistic understanding can often not be achieved from experiments in vivo alone. Since the discovery of the Z-ring more than 30 years ago, in vitro reconstitution experiments have been crucial to shed light on molecular processes normally hidden in the complex environment of the living cell. In this review, we summarize how rebuilding the divisome from purified components - or at least parts of it - have been instrumental to obtain the detailed mechanistic understanding of the bacterial cell division machinery that we have today.
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Affiliation(s)
- Philipp Radler
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria; University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.
| | - Martin Loose
- Institute for Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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2
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Arslan FN, Hannezo É, Merrin J, Loose M, Heisenberg CP. Adhesion-induced cortical flows pattern E-cadherin-mediated cell contacts. Curr Biol 2024; 34:171-182.e8. [PMID: 38134934 DOI: 10.1016/j.cub.2023.11.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/25/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
Metazoan development relies on the formation and remodeling of cell-cell contacts. Dynamic reorganization of adhesion receptors and the actomyosin cell cortex in space and time plays a central role in cell-cell contact formation and maturation. Nevertheless, how this process is mechanistically achieved when new contacts are formed remains unclear. Here, by building a biomimetic assay composed of progenitor cells adhering to supported lipid bilayers functionalized with E-cadherin ectodomains, we show that cortical F-actin flows, driven by the depletion of myosin-2 at the cell contact center, mediate the dynamic reorganization of adhesion receptors and cell cortex at the contact. E-cadherin-dependent downregulation of the small GTPase RhoA at the forming contact leads to both a depletion of myosin-2 and a decrease of F-actin at the contact center. At the contact rim, in contrast, myosin-2 becomes enriched by the retraction of bleb-like protrusions, resulting in a cortical tension gradient from the contact rim to its center. This tension gradient, in turn, triggers centrifugal F-actin flows, leading to further accumulation of F-actin at the contact rim and the progressive redistribution of E-cadherin from the contact center to the rim. Eventually, this combination of actomyosin downregulation and flows at the contact determines the characteristic molecular organization, with E-cadherin and F-actin accumulating at the contact rim, where they are needed to mechanically link the contractile cortices of the adhering cells.
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Affiliation(s)
- Feyza Nur Arslan
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria; Institute of Bioengineering, École polytechnique fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Édouard Hannezo
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Jack Merrin
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Martin Loose
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
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De Franceschi N, Pezeshkian W, Fragasso A, Bruininks BMH, Tsai S, Marrink SJ, Dekker C. Synthetic Membrane Shaper for Controlled Liposome Deformation. ACS NANO 2022; 17:966-978. [PMID: 36441529 PMCID: PMC9878720 DOI: 10.1021/acsnano.2c06125] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 11/18/2022] [Indexed: 06/16/2023]
Abstract
Shape defines the structure and function of cellular membranes. In cell division, the cell membrane deforms into a "dumbbell" shape, while organelles such as the autophagosome exhibit "stomatocyte" shapes. Bottom-up in vitro reconstitution of protein machineries that stabilize or resolve the membrane necks in such deformed liposome structures is of considerable interest to characterize their function. Here we develop a DNA-nanotechnology-based approach that we call the synthetic membrane shaper (SMS), where cholesterol-linked DNA structures attach to the liposome membrane to reproducibly generate high yields of stomatocytes and dumbbells. In silico simulations confirm the shape-stabilizing role of the SMS. We show that the SMS is fully compatible with protein reconstitution by assembling bacterial divisome proteins (DynaminA, FtsZ:ZipA) at the catenoidal neck of these membrane structures. The SMS approach provides a general tool for studying protein binding to complex membrane geometries that will greatly benefit synthetic cell research.
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Affiliation(s)
- Nicola De Franceschi
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZDelft, The Netherlands
| | - Weria Pezeshkian
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AGGroningen, The Netherlands
- The
Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, 17DK-2100Copenhagen, Denmark
| | - Alessio Fragasso
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZDelft, The Netherlands
| | - Bart M. H. Bruininks
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AGGroningen, The Netherlands
| | - Sean Tsai
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZDelft, The Netherlands
| | - Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute and Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AGGroningen, The Netherlands
| | - Cees Dekker
- Department
of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZDelft, The Netherlands
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Radler P, Baranova N, Caldas P, Sommer C, López-Pelegrín M, Michalik D, Loose M. In vitro reconstitution of Escherichia coli divisome activation. Nat Commun 2022; 13:2635. [PMID: 35550516 PMCID: PMC9098913 DOI: 10.1038/s41467-022-30301-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 04/25/2022] [Indexed: 01/02/2023] Open
Abstract
The actin-homologue FtsA is essential for E. coli cell division, as it links FtsZ filaments in the Z-ring to transmembrane proteins. FtsA is thought to initiate cell constriction by switching from an inactive polymeric to an active monomeric conformation, which recruits downstream proteins and stabilizes the Z-ring. However, direct biochemical evidence for this mechanism is missing. Here, we use reconstitution experiments and quantitative fluorescence microscopy to study divisome activation in vitro. By comparing wild-type FtsA with FtsA R286W, we find that this hyperactive mutant outperforms FtsA WT in replicating FtsZ treadmilling dynamics, FtsZ filament stabilization and recruitment of FtsN. We could attribute these differences to a faster exchange and denser packing of FtsA R286W below FtsZ filaments. Using FRET microscopy, we also find that FtsN binding promotes FtsA self-interaction. We propose that in the active divisome FtsA and FtsN exist as a dynamic copolymer that follows treadmilling filaments of FtsZ. In E. coli, FtsA and FtsZ control the place and time of cell division. Here, the authors use in vitro experiments to show how FtsA can follow FtsZ treadmilling and that downstream proteins form dynamic copolymers with FtsA to initiate division.
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Affiliation(s)
- Philipp Radler
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Natalia Baranova
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria.,University of Vienna, Department of Pharmaceutical Sciences, Vienna, Austria
| | - Paulo Caldas
- UCIBIO-Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade Nova de Lisboa, Caparica, Portugal
| | - Christoph Sommer
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mar López-Pelegrín
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - David Michalik
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Martin Loose
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria.
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Lucidi M, Hristu R, Nichele L, Stanciu GA, Tranca DE, Holban AM, Visca P, Stanciu SG, Cincotti G. STED nanoscopy of KK114-stained pathogenic bacteria. JOURNAL OF BIOPHOTONICS 2020; 13:e202000097. [PMID: 32483852 DOI: 10.1002/jbio.202000097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/11/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Super-resolution microscopy techniques can provide answers to still pending questions on prokaryotic organisms but are yet to be used at their full potential for this purpose. To address this, we evaluate the ability of the rhodamine-like KK114 dye to label various types of bacteria, to enable imaging of fine structural details with stimulated emission depletion microscopy (STED). We assessed fluorescent labeling with KK114 for eleven Gram-positive and Gram-negative bacterial species and observed that this contrast agent binds to their cell membranes. Significant differences in the labeling outputs were noticed across the tested bacterial species, but importantly, KK114-staining allowed the observation of subtle nanometric cell details in some cases. For example, a helix pattern resembling a cytoskeleton arrangement was detected in Bacillus subtilis. Furthermore, we found that KK114 easily penetrates the membrane of bacterial microorganism that lost their viability, which can be useful to discriminate between living and dead cells.
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Affiliation(s)
| | - Radu Hristu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | | | - George A Stanciu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | - Denis E Tranca
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
| | - Alina Maria Holban
- Microbiology and Immunology Department, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Paolo Visca
- Department of Sciences, University Roma Tre, Rome, Italy
| | - Stefan G Stanciu
- Center for Microscopy - Microanalysis and Information Processing, University Politehnica of Bucharest, Bucharest, Romania
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Abstract
The polymerization-depolymerization dynamics of cytoskeletal proteins play essential roles in the self-organization of cytoskeletal structures, in eukaryotic as well as prokaryotic cells. While advances in fluorescence microscopy and in vitro reconstitution experiments have helped to study the dynamic properties of these complex systems, methods that allow to collect and analyze large quantitative datasets of the underlying polymer dynamics are still missing. Here, we present a novel image analysis workflow to study polymerization dynamics of active filaments in a nonbiased, highly automated manner. Using treadmilling filaments of the bacterial tubulin FtsZ as an example, we demonstrate that our method is able to specifically detect, track and analyze growth and shrinkage of polymers, even in dense networks of filaments. We believe that this automated method can facilitate the analysis of a large variety of dynamic cytoskeletal systems, using standard time-lapse movies obtained from experiments in vitro as well as in the living cell. Moreover, we provide scripts implementing this method as supplementary material.
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Baranova N, Radler P, Hernández-Rocamora VM, Alfonso C, López-Pelegrín M, Rivas G, Vollmer W, Loose M. Diffusion and capture permits dynamic coupling between treadmilling FtsZ filaments and cell division proteins. Nat Microbiol 2020; 5:407-417. [PMID: 31959972 PMCID: PMC7048620 DOI: 10.1038/s41564-019-0657-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 12/06/2019] [Indexed: 11/14/2022]
Abstract
Most bacteria accomplish cell division with the help of a dynamic protein complex called the divisome, which spans the cell envelope in the plane of division. Assembly and activation of this machinery is coordinated by the tubulin-related GTPase FtsZ, which was found to form treadmilling filaments on supported bilayers in vitro1 and in live cells where they circle around the cell division site2,3. Treadmilling of FtsZ is thought to actively move proteins around the cell thereby distributing peptidoglycan synthesis and coordinating the inward growth of the septum to form the new poles of the daughter cells4. However, the molecular mechanisms underlying this function are largely unknown. Here, to study how FtsZ polymerization dynamics are coupled to downstream proteins, we reconstituted part of the bacterial cell division machinery using its purified components FtsZ, FtsA and truncated transmembrane proteins essential for cell division. We found that the membrane-bound cytosolic peptides of FtsN and FtsQ co-migrated with treadmilling FtsZ-FtsA filaments, but despite their directed collective behavior, individual peptides showed random motion and transient confinement. Our work suggests that divisome proteins follow treadmilling FtsZ filaments by a diffusion-and-capture mechanism, which can give rise to a moving zone of signaling activity at the division site.
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Affiliation(s)
- Natalia Baranova
- Institute for Science and Technology Austria, Klosterneuburg, Austria
| | - Philipp Radler
- Institute for Science and Technology Austria, Klosterneuburg, Austria
| | | | | | | | - Germán Rivas
- Centro de Investigaciones Biológicas, Madrid, Spain
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Martin Loose
- Institute for Science and Technology Austria, Klosterneuburg, Austria.
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Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA. Nat Commun 2019; 10:5744. [PMID: 31848350 PMCID: PMC6917738 DOI: 10.1038/s41467-019-13702-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/21/2019] [Indexed: 11/25/2022] Open
Abstract
During bacterial cell division, the tubulin-homolog FtsZ forms a ring-like structure at the center of the cell. This Z-ring not only organizes the division machinery, but treadmilling of FtsZ filaments was also found to play a key role in distributing proteins at the division site. What regulates the architecture, dynamics and stability of the Z-ring is currently unknown, but FtsZ-associated proteins are known to play an important role. Here, using an in vitro reconstitution approach, we studied how the well-conserved protein ZapA affects FtsZ treadmilling and filament organization into large-scale patterns. Using high-resolution fluorescence microscopy and quantitative image analysis, we found that ZapA cooperatively increases the spatial order of the filament network, but binds only transiently to FtsZ filaments and has no effect on filament length and treadmilling velocity. Together, our data provides a model for how FtsZ-associated proteins can increase the precision and stability of the bacterial cell division machinery in a switch-like manner. The Z-ring, constituted of the tubulin homolog FtsZ protein, plays an essential role for bacterial cell division. Here the authors use an in vitro reconstitution approach to determine how the regulatory protein ZapA affects FtsZ treadmilling and filament organization into large-scale patterns.
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