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Käshammer L, van den Ent F, Jeffery M, Jean NL, Hale VL, Löwe J. Cryo-EM structure of the bacterial divisome core complex and antibiotic target FtsWIQBL. Nat Microbiol 2023:10.1038/s41564-023-01368-0. [PMID: 37127704 DOI: 10.1038/s41564-023-01368-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
In most bacteria, cell division relies on the synthesis of new cell wall material by the multiprotein divisome complex. Thus, at the core of the divisome are the transglycosylase FtsW, which synthesises peptidoglycan strands from its substrate Lipid II, and the transpeptidase FtsI that cross-links these strands to form a mesh, shaping and protecting the bacterial cell. The FtsQ-FtsB-FtsL trimeric complex interacts with the FtsWI complex and is involved in regulating its enzymatic activities; however, the structure of this pentameric complex is unknown. Here, we present the cryogenic electron microscopy structure of the FtsWIQBL complex from Pseudomonas aeruginosa at 3.7 Å resolution. Our work reveals intricate structural details, including an extended coiled coil formed by FtsL and FtsB and the periplasmic interaction site between FtsL and FtsI. Our structure explains the consequences of previously reported mutations and we postulate a possible activation mechanism involving a large conformational change in the periplasmic domain. As FtsWIQBL is central to the divisome, our structure is foundational for the design of future experiments elucidating the precise mechanism of bacterial cell division, an important antibiotic target.
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Affiliation(s)
- Lisa Käshammer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Magnus Jeffery
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Nicolas L Jean
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Victoria L Hale
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jan Löwe
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
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2
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Nguyen HTV, Chen X, Parada C, Luo AC, Shih O, Jeng US, Huang CY, Shih YL, Ma C. Structure of the heterotrimeric membrane protein complex FtsB-FtsL-FtsQ of the bacterial divisome. Nat Commun 2023; 14:1903. [PMID: 37019934 PMCID: PMC10076392 DOI: 10.1038/s41467-023-37543-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 03/21/2023] [Indexed: 04/07/2023] Open
Abstract
The synthesis of the cell-wall peptidoglycan during bacterial cell division is mediated by a multiprotein machine, called the divisome. The essential membrane protein complex of FtsB, FtsL and FtsQ (FtsBLQ) is at the heart of the divisome assembly cascade in Escherichia coli. This complex regulates the transglycosylation and transpeptidation activities of the FtsW-FtsI complex and PBP1b via coordination with FtsN, the trigger for the onset of constriction. Yet the underlying mechanism of FtsBLQ-mediated regulation is largely unknown. Here, we report the full-length structure of the heterotrimeric FtsBLQ complex, which reveals a V-shaped architecture in a tilted orientation. Such a conformation could be strengthened by the transmembrane and the coiled-coil domains of the FtsBL heterodimer, as well as an extended β-sheet of the C-terminal interaction site involving all three proteins. This trimeric structure may also facilitate interactions with other divisome proteins in an allosteric manner. These results lead us to propose a structure-based model that delineates the mechanism of the regulation of peptidoglycan synthases by the FtsBLQ complex.
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Affiliation(s)
- Hong Thuy Vy Nguyen
- Genomics Research Center, Academia Sinica, Taipei, 115, Taiwan
- Chemical Biology and Molecular Biophysics program, Taiwan International Graduate Program, Academia Sinica, Taipei, 115, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Xiaorui Chen
- Genomics Research Center, Academia Sinica, Taipei, 115, Taiwan
| | - Claudia Parada
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - An-Chi Luo
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115, Taiwan
| | - Orion Shih
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30044, Taiwan
| | - Chia-Ying Huang
- Paul Scherrer Institute, Forschungsstrasse 111, Villigen-PSI, 5232, Switzerland
| | - Yu-Ling Shih
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Biological Chemistry, Academia Sinica, Taipei, 115, Taiwan.
| | - Che Ma
- Genomics Research Center, Academia Sinica, Taipei, 115, Taiwan.
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3
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Chen YW, Kong WP, Wong KY. The structural integrity of the membrane-embedded bacterial division complex FtsQBL studied with molecular dynamics simulations. Comput Struct Biotechnol J 2023; 21:2602-2612. [PMID: 37114213 PMCID: PMC10126914 DOI: 10.1016/j.csbj.2023.03.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
The FtsQBL is an essential molecular complex sitting midway through bacterial divisome assembly. To visualize and understand its structure, and the consequences of its membrane anchorage, we produced a model of the E. coli complex using the deep-learning prediction utility, AlphaFold 2. The heterotrimeric model was inserted into a 3-lipid model membrane and subjected to a 500-ns atomistic molecular dynamics simulation. The model is superb in quality and captures most experimentally derived structural features, at both the secondary structure and the side-chain levels. The model consists of a uniquely interlocking module contributed by the C-terminal regions of all three proteins. The functionally important constriction control domain residues of FtsB and FtsL are located at a fixed vertical position of ∼43-49 Å from the membrane surface. While the periplasmic domains of all three proteins are well-defined and rigid, the single transmembrane helices of each are flexible and their collective twisting and bending contribute to most structural variations, according to principal component analysis. Considering FtsQ only, the protein is more flexible in its free state relative to its complexed state-with the biggest structural changes located at the elbow between the transmembrane helix and the α-domain. The disordered N-terminal domains of FtsQ and FtsL associate with the cytoplasmic surface of the inner membrane instead of freely venturing into the solvent. Contact network analysis highlighted the formation of the interlocking trimeric module in FtsQBL as playing a central role in mediating the overall structure of the complex.
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4
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Paulussen FM, Grossmann TN. Peptide-based covalent inhibitors of protein-protein interactions. J Pept Sci 2023; 29:e3457. [PMID: 36239115 PMCID: PMC10077911 DOI: 10.1002/psc.3457] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 12/13/2022]
Abstract
Protein-protein interactions (PPI) are involved in all cellular processes and many represent attractive therapeutic targets. However, the frequently rather flat and large interaction areas render the identification of small molecular PPI inhibitors very challenging. As an alternative, peptide interaction motifs derived from a PPI interface can serve as starting points for the development of inhibitors. However, certain proteins remain challenging targets when applying inhibitors with a competitive mode of action. For that reason, peptide-based ligands with an irreversible binding mode have gained attention in recent years. This review summarizes examples of covalent inhibitors that employ peptidic binders and have been tested in a biological context.
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Affiliation(s)
- Felix M Paulussen
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Department of Molecular Microbiology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Tom N Grossmann
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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5
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Paulussen FM, Schouten GK, Moertl C, Verheul J, Hoekstra I, Koningstein GM, Hutchins GH, Alkir A, Luirink RA, Geerke DP, van Ulsen P, den Blaauwen T, Luirink J, Grossmann TN. Covalent Proteomimetic Inhibitor of the Bacterial FtsQB Divisome Complex. J Am Chem Soc 2022; 144:15303-15313. [PMID: 35945166 PMCID: PMC9413201 DOI: 10.1021/jacs.2c06304] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The use of antibiotics is threatened by the emergence
and spread
of multidrug-resistant strains of bacteria. Thus, there is a need
to develop antibiotics that address new targets. In this respect,
the bacterial divisome, a multi-protein complex central to cell division,
represents a potentially attractive target. Of particular interest
is the FtsQB subcomplex that plays a decisive role in divisome assembly
and peptidoglycan biogenesis in E. coli. Here, we report the structure-based design of
a macrocyclic covalent inhibitor derived from a periplasmic region
of FtsB that mediates its binding to FtsQ. The bioactive conformation
of this motif was stabilized by a customized cross-link resulting
in a tertiary structure mimetic with increased affinity for FtsQ.
To increase activity, a covalent handle was incorporated, providing
an inhibitor that impedes the interaction between FtsQ and FtsB irreversibly. The covalent inhibitor reduced the growth of an outer
membrane-permeable E. coli strain,
concurrent with the expected loss of FtsB localization, and also affected
the infection of zebrafish larvae by a clinical E.
coli strain. This first-in-class inhibitor of a divisome
protein–protein interaction highlights the potential of proteomimetic
molecules as inhibitors of challenging targets. In particular, the
covalent mode-of-action can serve as an inspiration for future antibiotics
that target protein–protein interactions.
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Affiliation(s)
- Felix M Paulussen
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Department of Molecular Microbiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Gina K Schouten
- Medical Microbiology and Infection Control (MMI), Amsterdam UMC Location VUmc, De Boelelaan 1108, Amsterdam 1081 HZ, Netherlands
| | - Carolin Moertl
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Jolanda Verheul
- Department of Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Sciencepark 904, Amsterdam 1098 XH, Netherlands
| | - Irma Hoekstra
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Gregory M Koningstein
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Department of Molecular Microbiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - George H Hutchins
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Aslihan Alkir
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Rosa A Luirink
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Daan P Geerke
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Peter van Ulsen
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Department of Molecular Microbiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Tanneke den Blaauwen
- Department of Bacterial Cell Biology and Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Sciencepark 904, Amsterdam 1098 XH, Netherlands
| | - Joen Luirink
- Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Department of Molecular Microbiology, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
| | - Tom N Grossmann
- Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands.,Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, Netherlands
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6
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Buroni S, Makarov V, Scoffone VC, Trespidi G, Riccardi G, Chiarelli LR. The cell division protein FtsZ as a cellular target to hit cystic fibrosis pathogens. Eur J Med Chem 2020; 190:112132. [PMID: 32066012 DOI: 10.1016/j.ejmech.2020.112132] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/31/2020] [Accepted: 02/06/2020] [Indexed: 11/25/2022]
Abstract
Cystic fibrosis is a rare genetic disease characterized by the production of dehydrated mucus in the lung able to trap bacteria and rendering their proliferation particularly dangerous, thus leading to chronic infections. Among these bacteria, Staphylococcus aureus and Pseudomonas aeruginosa play a major role while, within emerging pathogens, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex species, as well as non-tuberculous mycobacteria are listed. Since a common feature of these bacteria is the high level of drug resistance, cell division, and in particular FtsZ, has been explored as a novel therapeutic target for the design of new molecules with antibacterial properties. This review summarizes and provides insight into recent advances in the discovery of compounds targeting FtsZ: the majority of them exhibit anti-staphylococcal activity, while a few were directed against the cystic fibrosis Gram negative pathogens.
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Affiliation(s)
- Silvia Buroni
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Vadim Makarov
- Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Moscow, Russia
| | - Viola Camilla Scoffone
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Gabriele Trespidi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Giovanna Riccardi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Laurent R Chiarelli
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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7
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Interrogating the Essential Bacterial Cell Division Protein FtsQ with Fragments Using Target Immobilized NMR Screening (TINS). Int J Mol Sci 2019; 20:ijms20153684. [PMID: 31357624 PMCID: PMC6695665 DOI: 10.3390/ijms20153684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/20/2019] [Accepted: 07/22/2019] [Indexed: 11/17/2022] Open
Abstract
The divisome is a large protein complex that regulates bacterial cell division and therefore represents an attractive target for novel antibacterial drugs. In this study, we report on the ligandability of FtsQ, which is considered a key component of the divisome. For this, the soluble periplasmic domain of Escherichia coli FtsQ was immobilized and used to screen a library of 1501 low molecular weight (< 300 Da), synthetic compounds for those that interact with the protein. A primary screen was performed using target immobilized NMR screening (TINS) and yielded 72 hits. Subsequently, these hits were validated in an orthogonal assay. At first, we aimed to do this using surface plasmon resonance (SPR), but the lack of positive control hampered optimization of the experiment. Alternatively, a two-dimensional heteronuclear single quantum coherence (HSQC) NMR spectrum of FtsQ was obtained and used to validate these hits by chemical shift perturbation (CSP) experiments. This resulted in the identification of three fragments with weak affinity for the periplasmic domain of FtsQ, arguing that the ligandability of FtsQ is low. While this indicates that developing high affinity ligands for FtsQ is far from straightforward, the identified hit fragments can help to further interrogate FtsQ interactions.
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8
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Meiresonne NY, Consoli E, Mertens LM, Chertkova AO, Goedhart J, den Blaauwen T. Superfolder mTurquoise2 ox optimized for the bacterial periplasm allows high efficiency in vivo FRET of cell division antibiotic targets. Mol Microbiol 2019; 111:1025-1038. [PMID: 30648295 PMCID: PMC6850650 DOI: 10.1111/mmi.14206] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2019] [Indexed: 11/30/2022]
Abstract
Fluorescent proteins (FPs) are of vital importance to biomedical research. Many of the currently available fluorescent proteins do not fluoresce when expressed in non-native environments, such as the bacterial periplasm. This strongly limits the options for applications that employ multiple FPs, such as multiplex imaging and Förster resonance energy transfer (FRET). To address this issue, we have engineered a new cyan fluorescent protein based on mTurquoise2 (mTq2). The new variant is dubbed superfolder turquoise2ox (sfTq2ox ) and is able to withstand challenging, oxidizing environments. sfTq2ox has improved folding capabilities and can be expressed in the periplasm at higher concentrations without toxicity. This was tied to the replacement of native cysteines that may otherwise form promiscuous disulfide bonds. The improved sfTq2ox has the same spectroscopic properties as mTq2, that is, high fluorescence lifetime and quantum yield. The sfTq2ox -mNeongreen FRET pair allows the detection of periplasmic protein-protein interactions with energy transfer rates exceeding 40%. Employing the new FRET pair, we show the direct interaction of two essential periplasmic cell division proteins FtsL and FtsB and disrupt it by mutations, paving the way for in vivo antibiotic screening. SIGNIFICANCE: The periplasmic space of Gram-negative bacteria contains many regulatory, transport and cell wall-maintaining proteins. A preferred method to investigate these proteins in vivo is by the detection of fluorescent protein fusions. This is challenging since most fluorescent proteins do not fluoresce in the oxidative environment of the periplasm. We assayed popular fluorescent proteins for periplasmic functionality and describe key factors responsible for periplasmic fluorescence. Using this knowledge, we engineered superfolder mTurquoise2ox (sfTq2ox ), a new cyan fluorescent protein, capable of bright fluorescence in the periplasm. We show that our improvements come without a trade-off from its parent mTurquoise2. Employing sfTq2ox as FRET donor, we show the direct in vivo interaction and disruption of unique periplasmic antibiotic targets FtsB and FtsL.
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Affiliation(s)
- Nils Y. Meiresonne
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Elisa Consoli
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Laureen M.Y. Mertens
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Anna O. Chertkova
- Molecular Cytology and van Leeuwenhoek Centre for Advanced MicroscopySwammerdam Institute for Life Sciences, University of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Joachim Goedhart
- Molecular Cytology and van Leeuwenhoek Centre for Advanced MicroscopySwammerdam Institute for Life Sciences, University of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Tanneke den Blaauwen
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life SciencesUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
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9
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Miyazaki R, Akiyama Y, Mori H. A photo-cross-linking approach to monitor protein dynamics in living cells. Biochim Biophys Acta Gen Subj 2019; 1864:129317. [PMID: 30851405 DOI: 10.1016/j.bbagen.2019.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/26/2019] [Accepted: 03/04/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND Proteins, which comprise one of the major classes of biomolecules that constitute a cell, interact with other cellular factors during both their biogenesis and functional states. Studying not only static but also transient interactions of proteins is important to understand their physiological roles and regulation mechanisms. However, only a limited number of methods are available to analyze the dynamic behaviors of proteins at the molecular level in a living cell. The site-directed in vivo photo-cross-linking approach is an elegant technique to capture protein interactions with high spatial resolution in a living cell. SCOPE OF REVIEW Here, we review the in vivo photo-cross-linking approach including its recent applications and the potential problems to be considered. We also introduce a new in vivo photo-cross-linking-based technique (PiXie) to study protein dynamics with high spatiotemporal resolution. MAJOR CONCLUSIONS In vivo photo-cross-linking enables us to capture weak/transient protein interactions with high spatial resolution, and allows for identification of interacting factors. Moreover, the PiXie approach can be used to monitor rapid folding/assembly processes of proteins in living cells. GENERAL SIGNIFICANCE In vivo photo-cross-linking is a simple method that has been used to analyze the dynamic interactions of many cellular proteins. Originally developed in Escherichia coli, this system has been extended to studies in various organisms, making it a fundamental technique for investigating dynamic protein interactions in many cellular processes. This article is part of a Special issue entitled "Novel major techniques for visualizing 'live' protein molecules" edited by Dr. Daisuke Kohda.
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Affiliation(s)
- Ryoji Miyazaki
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Yoshinori Akiyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Hiroyuki Mori
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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10
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Abstract
Assembly of the division machinery in Gram-negative and Gram-positive bacteria occurs in two time-dependent steps. First, the FtsZ proto-ring localizes at midcell including some FtsN molecules. Assembly of the division machinery in Gram-negative and Gram-positive bacteria occurs in two time-dependent steps. First, the FtsZ proto-ring localizes at midcell including some FtsN molecules. Subsequently, the proteins that catalyze and regulate septal peptidoglycan (PG) synthesis are recruited including among others, the FtsBLQ-PB1B-FtsW-PBP3 complex. Further accumulation of FtsN finally allows initiation of cell division. It was known that FtsA and FtsQLB somehow prevented this initiation. Recently, A. Boes, S. Olatunji, E. Breukink, and M. Terrak (mBio 10:e01912-18, 2019, https://doi.org/10.1128/mBio.01912-18) reported that this is caused by inhibition of the activity of the PG synthases by FtsBLQ, which has to be outcompeted by accumulation of the PBP1b activating FtsN. This supports a central structural as well as regulatory role for the FtsBLQ protein complex that is conserved only in prokaryotes, making it an attractive target for antibiotic development.
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11
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Direct Interaction between the Two Z Ring Membrane Anchors FtsA and ZipA. J Bacteriol 2019; 201:JB.00579-18. [PMID: 30478085 DOI: 10.1128/jb.00579-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/19/2018] [Indexed: 12/14/2022] Open
Abstract
The initiation of Escherichia coli cell division requires three proteins, FtsZ, FtsA, and ZipA, which assemble in a dynamic ring-like structure at midcell. Along with the transmembrane protein ZipA, the actin-like FtsA helps to tether treadmilling polymers of tubulin-like FtsZ to the membrane. In addition to forming homo-oligomers, FtsA and ZipA interact directly with the C-terminal conserved domain of FtsZ. Gain-of-function mutants of FtsA are deficient in forming oligomers and can bypass the need for ZipA, suggesting that ZipA may normally function to disrupt FtsA oligomers, although no direct interaction between FtsA and ZipA has been reported. Here, we use in vivo cross-linking to show that FtsA and ZipA indeed interact directly. We identify the exposed surface of FtsA helix 7, which also participates in binding to ATP through its internal surface, as a key interface needed for the interaction with ZipA. This interaction suggests that FtsZ's membrane tethers may regulate each other's activities.IMPORTANCE To divide, most bacteria first construct a protein machine at the plane of division and then recruit the machinery that will synthesize the division septum. In Escherichia coli, this first stage involves the assembly of FtsZ polymers at midcell, which directly bind to membrane-associated proteins FtsA and ZipA to form a discontinuous ring structure. Although FtsZ directly binds both FtsA and ZipA, it is unclear why FtsZ requires two separate membrane tethers. Here, we uncover a new direct interaction between the tethers, which involves a helix within FtsA that is adjacent to its ATP binding pocket. Our findings imply that in addition to their known roles as FtsZ membrane anchors, FtsA and ZipA may regulate each other's structure and function.
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12
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Structural Insights into the FtsQ/FtsB/FtsL Complex, a Key Component of the Divisome. Sci Rep 2018; 8:18061. [PMID: 30584256 PMCID: PMC6305486 DOI: 10.1038/s41598-018-36001-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 11/13/2018] [Indexed: 11/17/2022] Open
Abstract
Bacterial cell division is a fundamental process that results in the physical separation of a mother cell into two daughter cells and involves a set of proteins known as the divisome. Among them, the FtsQ/FtsB/FtsL complex was known as a scaffold protein complex, but its overall structure and exact function is not precisely known. In this study, we have determined the crystal structure of the periplasmic domain of FtsQ in complex with the C-terminal fragment of FtsB, and showed that the C-terminal region of FtsB is a key binding region of FtsQ via mutational analysis in vitro and in vivo. We also obtained the solution structure of the periplasmic FtsQ/FtsB/FtsL complex by small angle X-ray scattering (SAXS), which reveals its structural organization. Interestingly, the SAXS and analytical gel filtration data showed that the FtsQ/FtsB/FtsL complex forms a 2:2:2 heterohexameric assembly in solution with the “Y” shape. Based on the model, the N-terminal directions of FtsQ and the FtsB/FtsL complex should be opposite, suggesting that the Y-shaped FtsQ/FtsB/FtsL complex might fit well into the curved membrane for membrane anchoring.
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13
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Abstract
In most bacteria and archaea, filaments of FtsZ protein organize cell division. FtsZ forms a ring structure at the division site and starts the recruitment of 10 to 20 downstream proteins that together form a multiprotein complex termed the divisome. The divisome is thought to facilitate many of the steps required to make two cells out of one. FtsQ and FtsB are part of the divisome, with FtsQ being a central hub, interacting with most of the other divisome components. Here we show for the first time in detail how FtsQ interacts with its downstream partner FtsB and show that mutations that disturb the interface between the two proteins effectively inhibit cell division. Most bacteria and archaea use the tubulin homologue FtsZ as its central organizer of cell division. In Gram-negative Escherichia coli bacteria, FtsZ recruits cytosolic, transmembrane, periplasmic, and outer membrane proteins, assembling the divisome that facilitates bacterial cell division. One such divisome component, FtsQ, a bitopic membrane protein with a globular domain in the periplasm, has been shown to interact with many other divisome proteins. Despite its otherwise unknown function, it has been shown to be a major divisome interaction hub. Here, we investigated the interactions of FtsQ with FtsB and FtsL, two small bitopic membrane proteins that act immediately downstream of FtsQ. We show in biochemical assays that the periplasmic domains of E. coli FtsB and FtsL interact with FtsQ, but not with each other. Our crystal structure of FtsB bound to the β domain of FtsQ shows that only residues 64 to 87 of FtsB interact with FtsQ. A synthetic peptide comprising those 24 FtsB residues recapitulates the FtsQ-FtsB interactions. Protein deletions and structure-guided mutant analyses validate the structure. Furthermore, the same structure-guided mutants show cell division defects in vivo that are consistent with our structure of the FtsQ-FtsB complex that shows their interactions as they occur during cell division. Our work provides intricate details of the interactions within the divisome and also provides a tantalizing view of a highly conserved protein interaction in the periplasm of bacteria that is an excellent target for cell division inhibitor searches.
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14
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Outer membrane lipoprotein RlpA is a novel periplasmic interaction partner of the cell division protein FtsK in Escherichia coli. Sci Rep 2018; 8:12933. [PMID: 30154462 PMCID: PMC6113214 DOI: 10.1038/s41598-018-30979-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 08/07/2018] [Indexed: 12/30/2022] Open
Abstract
In Escherichia coli, formation of new cells is mediated by the elongasome and divisome that govern cell elongation and septation, respectively. Proper transition between these events is essential to ensure viable progeny are produced; however, the components of each complex responsible for transmission of the cell signal to shift from elongation to septation are unclear. Recently, a region within the N-terminal domain of the essential divisome protein FtsK (FtsKN) was identified that points to a key role for FtsK as a checkpoint of cell envelope remodeling during division. Here, we used site-specific in vivo UV cross-linking to probe the periplasmic loops of FtsKN for protein interaction partners critical for FtsKN function. Mass spectrometry analysis of five unique FtsKN periplasmic cross-links revealed a network of potential FtsKN interactors, one of which included the septal peptidoglycan binding protein rare lipoprotein A (RlpA). This protein was further verified as a novel interaction partner of FtsKN by an in vitro pull-down assay. Deletion of rlpA from an FtsK temperature-sensitive E. coli strain partially restored cell growth and largely suppressed cellular filamentation compared to the wild-type strain. This suggests that interaction with RlpA may be critical in suppressing septation until proper assembly of the divisome.
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15
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Condon SGF, Mahbuba DA, Armstrong CR, Diaz-Vazquez G, Craven SJ, LaPointe LM, Khadria AS, Chadda R, Crooks JA, Rangarajan N, Weibel DB, Hoskins AA, Robertson JL, Cui Q, Senes A. The FtsLB subcomplex of the bacterial divisome is a tetramer with an uninterrupted FtsL helix linking the transmembrane and periplasmic regions. J Biol Chem 2018; 293:1623-1641. [PMID: 29233891 PMCID: PMC5798294 DOI: 10.1074/jbc.ra117.000426] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/04/2017] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli, FtsLB plays a central role in the initiation of cell division, possibly transducing a signal that will eventually lead to the activation of peptidoglycan remodeling at the forming septum. The molecular mechanisms by which FtsLB operates in the divisome, however, are not understood. Here, we present a structural analysis of the FtsLB complex, performed with biophysical, computational, and in vivo methods, that establishes the organization of the transmembrane region and proximal coiled coil of the complex. FRET analysis in vitro is consistent with formation of a tetramer composed of two FtsL and two FtsB subunits. We predicted subunit contacts through co-evolutionary analysis and used them to compute a structural model of the complex. The transmembrane region of FtsLB is stabilized by hydrophobic packing and by a complex network of hydrogen bonds. The coiled coil domain probably terminates near the critical constriction control domain, which might correspond to a structural transition. The presence of strongly polar amino acids within the core of the tetrameric coiled coil suggests that the coil may split into two independent FtsQ-binding domains. The helix of FtsB is interrupted between the transmembrane and coiled coil regions by a flexible Gly-rich linker. Conversely, the data suggest that FtsL forms an uninterrupted helix across the two regions and that the integrity of this helix is indispensable for the function of the complex. The FtsL helix is thus a candidate for acting as a potential mechanical connection to communicate conformational changes between periplasmic, membrane, and cytoplasmic regions.
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Affiliation(s)
- Samson G F Condon
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | - Deena-Al Mahbuba
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | | | | | - Samuel J Craven
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | - Loren M LaPointe
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | - Ambalika S Khadria
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | - Rahul Chadda
- the Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - John A Crooks
- From the Department of Biochemistry
- the Integrated Program in Biochemistry
| | | | | | | | - Janice L Robertson
- the Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Qiang Cui
- the Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 and
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16
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Peschke M, Le Goff M, Koningstein GM, Karyolaimos A, de Gier JW, van Ulsen P, Luirink J. SRP, FtsY, DnaK and YidC Are Required for the Biogenesis of the E. coli Tail-Anchored Membrane Proteins DjlC and Flk. J Mol Biol 2017; 430:389-403. [PMID: 29246766 DOI: 10.1016/j.jmb.2017.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/19/2022]
Abstract
Tail-anchored membrane proteins (TAMPs) are relatively simple membrane proteins characterized by a single transmembrane domain (TMD) at their C-terminus. Consequently, the hydrophobic TMD, which acts as a subcellular targeting signal, emerges from the ribosome only after termination of translation precluding canonical co-translational targeting and membrane insertion. In contrast to the well-studied eukaryotic TAMPs, surprisingly little is known about the cellular components that facilitate the biogenesis of bacterial TAMPs. In this study, we identify DjlC and Flk as bona fide Escherichia coli TAMPs and show that their TMDs are necessary and sufficient for authentic membrane targeting of the fluorescent reporter mNeonGreen. Using strains conditional for the expression of known E. coli membrane targeting and insertion factors, we demonstrate that the signal recognition particle (SRP), its receptor FtsY, the chaperone DnaK and insertase YidC are each required for efficient membrane localization of both TAMPs. A close association between the TMD of DjlC and Flk with both the Ffh subunit of SRP and YidC was confirmed by site-directed in vivo photo-crosslinking. In addition, our data suggest that the hydrophobicity of the TMD correlates with the dependency on SRP for efficient targeting.
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Affiliation(s)
- Markus Peschke
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Mélanie Le Goff
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Gregory M Koningstein
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Alexandros Karyolaimos
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Svante Arrhenius väg 16C, SE-106 91 Stockholm, Sweden
| | - Jan-Willem de Gier
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, Svante Arrhenius väg 16C, SE-106 91 Stockholm, Sweden
| | - Peter van Ulsen
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands
| | - Joen Luirink
- The Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081, HV, Amsterdam, the Netherlands.
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17
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Screening for transmembrane association in divisome proteins using TOXGREEN, a high-throughput variant of the TOXCAT assay. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2573-2583. [PMID: 27453198 DOI: 10.1016/j.bbamem.2016.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 11/21/2022]
Abstract
TOXCAT is a widely used genetic assay to study interactions of transmembrane helices within the inner membrane of the bacterium Escherichia coli. TOXCAT is based on a fusion construct that links a transmembrane domain of interest with a cytoplasmic DNA-binding domain from the Vibrio cholerae ToxR protein. Interaction driven by the transmembrane domain results in dimerization of the ToxR domain, which, in turn, activates the expression of the reporter gene chloramphenicol acetyl transferase (CAT). Quantification of CAT is used as a measure of the ability of the transmembrane domain to self-associate. Because the quantification of CAT is relatively laborious, we developed a high-throughput variant of the assay, TOXGREEN, based on the expression of super-folded GFP and detection of fluorescence directly in unprocessed cell cultures. Careful side-by-side comparison of TOXCAT and TOXGREEN demonstrates that the methods have comparable response, dynamic range, sensitivity and intrinsic variability both in LB and minimal media. The greatly enhanced workflow makes TOXGREEN much more scalable and ideal for screening, since hundreds of constructs can be rapidly assessed in 96 well plates. Even for small scale investigations, TOXGREEN significantly reduces time, labor and cost associated with the procedure. We demonstrate applicability with a large screening for self-association among the transmembrane domains of bitopic proteins of the divisome (FtsL, FtsB, FtsQ, FtsI, FtsN, ZipA and EzrA) belonging to 11 bacterial species. The analysis confirms a previously reported tendency for FtsB to self-associate, and suggests that the transmembrane domains of ZipA, EzrA and FtsN may also possibly oligomerize.
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18
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Rowlett VW, Margolin W. The bacterial divisome: ready for its close-up. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0028. [PMID: 26370940 DOI: 10.1098/rstb.2015.0028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacterial cells divide by targeting a transmembrane protein machine to the division site and regulating its assembly and disassembly so that cytokinesis occurs at the correct time in the cell cycle. The structure and dynamics of this machine (divisome) in bacterial model systems are coming more clearly into focus, thanks to incisive cell biology methods in combination with biochemical and genetic approaches. The main conserved structural element of the machine is the tubulin homologue FtsZ, which assembles into a circumferential ring at the division site that is stabilized and anchored to the inner surface of the cytoplasmic membrane by FtsZ-binding proteins. Once this ring is in place, it recruits a series of transmembrane proteins that ultimately trigger cytokinesis. This review will survey the methods used to characterize the structure of the bacterial divisome, focusing mainly on the Escherichia coli model system, as well as the challenges that remain. These methods include recent super-resolution microscopy, cryo-electron tomography and synthetic reconstitution.
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Affiliation(s)
- Veronica W Rowlett
- Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
| | - William Margolin
- Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
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19
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Haeusser DP, Margolin W. Splitsville: structural and functional insights into the dynamic bacterial Z ring. Nat Rev Microbiol 2016; 14:305-19. [PMID: 27040757 DOI: 10.1038/nrmicro.2016.26] [Citation(s) in RCA: 216] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria must divide to increase in number and colonize their niche. Binary fission is the most widespread means of bacterial cell division, but even this relatively simple mechanism has many variations on a theme. In most bacteria, the tubulin homologue FtsZ assembles into a ring structure, termed the Z ring, at the site of cytokinesis and recruits additional proteins to form a large protein machine - the divisome - that spans the membrane. In this Review, we discuss current insights into the regulation of the assembly of the Z ring and how the divisome drives membrane invagination and septal cell wall growth while flexibly responding to various cellular inputs.
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Affiliation(s)
- Daniel P Haeusser
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin Street, Houston, Texas 77030, USA.,Biology Department, Canisius College, 2001 Main Street, Buffalo, New York 14208, USA
| | - William Margolin
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin Street, Houston, Texas 77030, USA
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20
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Glas M, van den Berg van Saparoea HB, McLaughlin SH, Roseboom W, Liu F, Koningstein GM, Fish A, den Blaauwen T, Heck AJR, de Jong L, Bitter W, de Esch IJP, Luirink J. The Soluble Periplasmic Domains of Escherichia coli Cell Division Proteins FtsQ/FtsB/FtsL Form a Trimeric Complex with Submicromolar Affinity. J Biol Chem 2015; 290:21498-509. [PMID: 26160297 DOI: 10.1074/jbc.m115.654756] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Indexed: 01/10/2023] Open
Abstract
Cell division in Escherichia coli involves a set of essential proteins that assembles at midcell to form the so-called divisome. The divisome regulates the invagination of the inner membrane, cell wall synthesis, and inward growth of the outer membrane. One of the divisome proteins, FtsQ, plays a central but enigmatic role in cell division. This protein associates with FtsB and FtsL, which, like FtsQ, are bitopic inner membrane proteins with a large periplasmic domain (denoted FtsQp, FtsBp, and FtsLp) that is indispensable for the function of each protein. Considering the vital nature and accessible location of the FtsQBL complex, it is an attractive target for protein-protein interaction inhibitors intended to block bacterial cell division. In this study, we expressed FtsQp, FtsBp, and FtsLp individually and in combination. Upon co-expression, FtsQp was co-purified with FtsBp and FtsLp from E. coli extracts as a stable trimeric complex. FtsBp was also shown to interact with FtsQp in the absence of FtsLp albeit with lower affinity. Interactions were mapped at the C terminus of the respective domains by site-specific cross-linking. The binding affinity and 1:1:1 stoichiometry of the FtsQpBpLp complex and the FtsQpBp subcomplex were determined in complementary surface plasmon resonance, analytical ultracentrifugation, and native mass spectrometry experiments.
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Affiliation(s)
- Marjolein Glas
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - H Bart van den Berg van Saparoea
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Stephen H McLaughlin
- the Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Winfried Roseboom
- the Swammerdam Institute for Life Sciences, Department of Mass Spectrometry of Biomacromolecules, and
| | - Fan Liu
- the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands, and
| | - Gregory M Koningstein
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Alexander Fish
- the NKI Protein Facility, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tanneke den Blaauwen
- Swammerdam Institute for Life Sciences, Department of Bacterial Cell Biology, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Albert J R Heck
- the Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, The Netherlands, and
| | - Luitzen de Jong
- the Swammerdam Institute for Life Sciences, Department of Mass Spectrometry of Biomacromolecules, and
| | - Wilbert Bitter
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Iwan J P de Esch
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Joen Luirink
- From the Amsterdam Institute of Molecules, Medicines and Systems, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands,
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21
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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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22
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Liu B, Persons L, Lee L, de Boer PAJ. Roles for both FtsA and the FtsBLQ subcomplex in FtsN-stimulated cell constriction in Escherichia coli. Mol Microbiol 2015; 95:945-70. [PMID: 25496160 DOI: 10.1111/mmi.12906] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2014] [Indexed: 12/18/2022]
Abstract
Escherichia coli FtsN is a bitopic membrane protein that is essential for triggering active cell constriction. A small periplasmic subdomain ((E) FtsN) is required and sufficient for function, but its mechanism of action is unclear. We isolated extragenic (E) FtsN*-suppressing mutations that restore division in cells producing otherwise non-functional variants of FtsN. These mapped to the IC domain of FtsA in the cytoplasm and to small subdomains of the FtsB and FtsL proteins in the periplasm. All FtsB and FtsL variants allowed survival without (E) FtsN, but many then imposed a new requirement for interaction between the cytoplasmic domain of FtsN ((N) FtsN) and FtsA. Alternatively, variants of FtsA, FtsB or FtsL acted synergistically to allow cell division in the complete absence of FtsN. Strikingly, moreover, substitution of a single residue in FtsB (E56) proved sufficient to rescue ΔftsN cells as well. In FtsN(+) cells, (E) FtsN*-suppressing mutations promoted cell fission at an abnormally small cell size, and caused cell shape and integrity defects under certain conditions. This and additional evidence support a model in which FtsN acts on either side of the membrane to induce a conformational switch in both FtsA and the FtsBLQ subcomplex to de-repress septal peptidoglycan synthesis and membrane invagination.
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Affiliation(s)
- Bing Liu
- Department of Molecular Biology & Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106-4960, USA
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23
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Berg KH, Straume D, Håvarstein LS. The function of the transmembrane and cytoplasmic domains of pneumococcal penicillin-binding proteins 2x and 2b extends beyond that of simple anchoring devices. Microbiology (Reading) 2014; 160:1585-1598. [DOI: 10.1099/mic.0.078535-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The biosynthesis of cell-wall peptidoglycan is a complex process that involves six different penicillin-binding proteins (PBPs) in Streptococcus pneumoniae. Two of these, PBP2x and PBP2b, are monofunctional transpeptidases that catalyse the formation of peptide cross-links between adjacent glycan strands. Both of them are bitopic membrane proteins with a small cytoplasmic and a large extracellular domain. PBP2x and PBP2b are essential for septal and peripheral peptidoglycan synthesis, respectively. Although several studies have investigated the properties of their extracellular catalytic domains, it is not known whether the role of their N-terminal non-catalytic domains extends beyond that of being simple anchoring devices. We therefore decided to use reciprocal domain swapping and mutational analysis to gain more information about the biological function of the membrane anchors and cytoplasmic tails of PBP2x and PBP2b. In the case of PBP2x both domains are essential, but neither the membrane anchor nor the cytoplasmic domain of PBP2x appear to serve as major localization signals. Instead, our results suggest that they are involved in interactions with other components of the divisome. Mutations of conserved amino acids in the cytoplasmic domain of PBP2x resulted in loss of function, underlining the importance of this region. The cytoplasmic domain of PBP2b could be swapped with the corresponding domain from PBP2x, whereas replacement of the PBP2b transmembrane domain with the corresponding PBP2x domain gave rise to slow-growing cells with grossly abnormal morphology. When both domains were exchanged simultaneously the cells were no longer viable.
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Affiliation(s)
- Kari Helene Berg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432, Ås, Norway
| | - Daniel Straume
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432, Ås, Norway
| | - Leiv Sigve Håvarstein
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432, Ås, Norway
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24
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Vicente M. Analysis and synthesis of the bacterial divisome. Environ Microbiol 2013. [DOI: 10.1111/1462-2920.12306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Miguel Vicente
- Centro Nacional de Biotecnología (CNB-CSIC); C/ Darwin n°3 E-28049 Madrid Spain
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25
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Khadria AS, Senes A. The transmembrane domains of the bacterial cell division proteins FtsB and FtsL form a stable high-order oligomer. Biochemistry 2013; 52:7542-50. [PMID: 24083359 DOI: 10.1021/bi4009837] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
FtsB and FtsL are two essential integral membrane proteins of the bacterial division complex or "divisome", both characterized by a single transmembrane helix and a juxtamembrane coiled coil domain. The two domains are important for the association of FtsB and FtsL, a key event for their recruitment to the divisome, which in turn allows the recruitment of the late divisomal components to the Z-ring and subsequent completion of the division process. Here we present a biophysical analysis performed in vitro that shows that the transmembrane domains of FtsB and FtsL associate strongly in isolation. Using Förster resonance energy transfer, we have measured the oligomerization of fluorophore-labeled transmembrane domains of FtsB and FtsL in both detergent and lipid. The data indicate that the transmembrane helices are likely a major contributor to the stability of the FtsB-FtsL complex. Our analyses show that FtsB and FtsL form a 1:1 higher-order oligomeric complex, possibly a tetramer. This finding suggests that the FtsB-FtsL complex is capable of multivalent binding to FtsQ and other divisome components, a hypothesis that is consistent with the possibility that the FtsB-FtsL complex has a structural role in the stabilization of the Z-ring.
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Affiliation(s)
- Ambalika S Khadria
- Department of Biochemistry, University of Wisconsin-Madison , 433 Babcock Drive, Madison, Wisconsin 53706, United States
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