1
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Martin FJO, Santiveri M, Hu H, Taylor NMI. Ion-driven rotary membrane motors: From structure to function. Curr Opin Struct Biol 2024; 88:102884. [PMID: 39053417 DOI: 10.1016/j.sbi.2024.102884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 05/16/2024] [Accepted: 06/21/2024] [Indexed: 07/27/2024]
Abstract
Ion-driven membrane motors, essential across all domains of life, convert a gradient of ions across a membrane into rotational energy, facilitating diverse biological processes including ATP synthesis, substrate transport, and bacterial locomotion. Herein, we highlight recent structural advances in the understanding of two classes of ion-driven membrane motors: rotary ATPases and 5:2 motors. The recent structure of the human F-type ATP synthase is emphasised along with the gained structural insight into clinically relevant mutations. Furthermore, we highlight the diverse roles of 5:2 motors and recent mechanistic understanding gained through the resolution of ions in the structure of a sodium-driven motor, combining insights into potential unifying mechanisms of ion selectivity and rotational torque generation in the context of their function as part of complex biological systems.
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Affiliation(s)
- Freddie J O Martin
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Mònica Santiveri
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Haidai Hu
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Nicholas M I Taylor
- Structural Biology of Molecular Machines Group, Protein Structure & Function Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
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2
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Lettermann L, Ziebert F, Schwarz US. A geometrical theory of gliding motility based on cell shape and surface flow. Proc Natl Acad Sci U S A 2024; 121:e2410708121. [PMID: 39028692 PMCID: PMC11287263 DOI: 10.1073/pnas.2410708121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/24/2024] [Indexed: 07/21/2024] Open
Abstract
Gliding motility proceeds with little changes in cell shape and often results from actively driven surface flows of adhesins binding to the extracellular environment. It allows for fast movement over surfaces or through tissue, especially for the eukaryotic parasites from the phylum apicomplexa, which includes the causative agents of the widespread diseases malaria and toxoplasmosis. We have developed a fully three-dimensional active particle theory which connects the self-organized, actively driven surface flow over a fixed cell shape to the resulting global motility patterns. Our analytical solutions and numerical simulations show that straight motion without rotation is unstable for simple shapes and that straight cell shapes tend to lead to pure rotations. This suggests that the curved shapes of Plasmodium sporozoites and Toxoplasma tachyzoites are evolutionary adaptations to avoid rotations without translation. Gliding motility is also used by certain myxo- or flavobacteria, which predominantly move on flat external surfaces and with higher control of cell surface flow through internal tracks. We extend our theory for these cases. We again find a competition between rotation and translation and predict the effect of internal track geometry on overall forward speed. While specific mechanisms might vary across species, in general, our geometrical theory predicts and explains the rotational, circular, and helical trajectories which are commonly observed for microgliders. Our theory could also be used to design synthetic microgliders.
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Affiliation(s)
- Leon Lettermann
- Institute for Theoretical Physics, Heidelberg University, Heidelberg69120, Germany
- Bioquant-Center, Heidelberg University, Heidelberg69120, Germany
| | - Falko Ziebert
- Institute for Theoretical Physics, Heidelberg University, Heidelberg69120, Germany
- Bioquant-Center, Heidelberg University, Heidelberg69120, Germany
| | - Ulrich S. Schwarz
- Institute for Theoretical Physics, Heidelberg University, Heidelberg69120, Germany
- Bioquant-Center, Heidelberg University, Heidelberg69120, Germany
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3
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Pérez-Burgos M, Herfurth M, Kaczmarczyk A, Harms A, Huber K, Jenal U, Glatter T, Søgaard-Andersen L. A deterministic, c-di-GMP-dependent program ensures the generation of phenotypically similar, symmetric daughter cells during cytokinesis. Nat Commun 2024; 15:6014. [PMID: 39019889 PMCID: PMC11255338 DOI: 10.1038/s41467-024-50444-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 07/10/2024] [Indexed: 07/19/2024] Open
Abstract
Phenotypic heterogeneity in bacteria can result from stochastic processes or deterministic programs. The deterministic programs often involve the versatile second messenger c-di-GMP, and give rise to daughter cells with different c-di-GMP levels by deploying c-di-GMP metabolizing enzymes asymmetrically during cell division. By contrast, less is known about how phenotypic heterogeneity is kept to a minimum. Here, we identify a deterministic c-di-GMP-dependent program that is hardwired into the cell cycle of Myxococcus xanthus to minimize phenotypic heterogeneity and guarantee the formation of phenotypically similar daughter cells during division. Cells lacking the diguanylate cyclase DmxA have an aberrant motility behaviour. DmxA is recruited to the cell division site and its activity is switched on during cytokinesis, resulting in a transient increase in the c-di-GMP concentration. During cytokinesis, this c-di-GMP burst ensures the symmetric incorporation and allocation of structural motility proteins and motility regulators at the new cell poles of the two daughters, thereby generating phenotypically similar daughters with correct motility behaviours. Thus, our findings suggest a general c-di-GMP-dependent mechanism for minimizing phenotypic heterogeneity, and demonstrate that bacteria can ensure the formation of dissimilar or similar daughter cells by deploying c-di-GMP metabolizing enzymes to distinct subcellular locations.
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Affiliation(s)
- María Pérez-Burgos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Marco Herfurth
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Andrea Harms
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Katrin Huber
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Urs Jenal
- Biozentrum, University of Basel, Basel, Switzerland
| | - Timo Glatter
- Core Facility for Mass Spectrometry & Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
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4
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Attia B, My L, Castaing JP, Dinet C, Le Guenno H, Schmidt V, Espinosa L, Anantharaman V, Aravind L, Sebban-Kreuzer C, Nouailler M, Bornet O, Viollier P, Elantak L, Mignot T. A molecular switch controls assembly of bacterial focal adhesions. SCIENCE ADVANCES 2024; 10:eadn2789. [PMID: 38809974 PMCID: PMC11135422 DOI: 10.1126/sciadv.adn2789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/23/2024] [Indexed: 05/31/2024]
Abstract
Cell motility universally relies on spatial regulation of focal adhesion complexes (FAs) connecting the substrate to cellular motors. In bacterial FAs, the Adventurous gliding motility machinery (Agl-Glt) assembles at the leading cell pole following a Mutual gliding-motility protein (MglA)-guanosine 5'-triphosphate (GTP) gradient along the cell axis. Here, we show that GltJ, a machinery membrane protein, contains cytosolic motifs binding MglA-GTP and AglZ and recruiting the MreB cytoskeleton to initiate movement toward the lagging cell pole. In addition, MglA-GTP binding triggers a conformational shift in an adjacent GltJ zinc-finger domain, facilitating MglB recruitment near the lagging pole. This prompts GTP hydrolysis by MglA, leading to complex disassembly. The GltJ switch thus serves as a sensor for the MglA-GTP gradient, controlling FA activity spatially.
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Affiliation(s)
- Bouchra Attia
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Laetitia My
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), Turing Center for Living Systems, CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Jean Philippe Castaing
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), Turing Center for Living Systems, CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Céline Dinet
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), Turing Center for Living Systems, CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Hugo Le Guenno
- Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Victoria Schmidt
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Leon Espinosa
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), Turing Center for Living Systems, CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Vivek Anantharaman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L. Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Corinne Sebban-Kreuzer
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Matthieu Nouailler
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Olivier Bornet
- Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Patrick Viollier
- Department of Microbiology and Molecular Medicine, Faculty of Medicine/Centre Médical Universitaire, University of Geneva, 1211 Genève 4, Switzerland
| | - Latifa Elantak
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie de la Méditerranée (IMM), CNRS - Aix-Marseille Université UMR7255, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne (LCB), Institut de Microbiologie de la Méditerranée (IMM), Turing Center for Living Systems, CNRS - Aix-Marseille Université UMR7283, 31 Chemin Joseph Aiguier CS70071, 13402 Marseille Cedex 20, France
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5
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Carbo CR, Faromiki OG, Nan B. A lytic transglycosylase connects bacterial focal adhesion complexes to the peptidoglycan cell wall. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588103. [PMID: 38617213 PMCID: PMC11014575 DOI: 10.1101/2024.04.04.588103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The Gram-negative bacterium Myxococcus xanthus glides on solid surfaces. Dynamic bacterial focal adhesion complexes (bFACs) convert proton motive force from the inner membrane into mechanical propulsion on the cell surface. It is unclear how the mechanical force transmits across the rigid peptidoglycan (PG) cell wall. Here we show that AgmT, a highly abundant lytic PG transglycosylase homologous to Escherichia coli MltG, couples bFACs to PG. Coprecipitation assay and single-particle microscopy reveal that the gliding motors fail to connect to PG and thus are unable to assemble into bFACs in the absence of an active AgmT. Heterologous expression of E. coli MltG restores the connection between PG and bFACs and thus rescues gliding motility in the M. xanthus cells that lack AgmT. Our results indicate that bFACs anchor to AgmT-modified PG to transmit mechanical force across the PG cell wall.
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Affiliation(s)
- Carlos Ramirez Carbo
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- The Genetics and Genomics Interdisciplinary Program, Texas A&M University, College Station, TX 77843, USA
- C. R. C and O. G. F. contribute equally to this work
| | - Olalekan G. Faromiki
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
- C. R. C and O. G. F. contribute equally to this work
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
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6
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Chen Y, Topo EJ, Nan B, Chen J. Mathematical modeling of mechanosensitive reversal control in Myxococcus xanthus. Front Microbiol 2024; 14:1294631. [PMID: 38260904 PMCID: PMC10803039 DOI: 10.3389/fmicb.2023.1294631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Adjusting motility patterns according to environmental cues is important for bacterial survival. Myxococcus xanthus, a bacterium moving on surfaces by gliding and twitching mechanisms, modulates the reversal frequency of its front-back polarity in response to mechanical cues like substrate stiffness and cell-cell contact. In this study, we propose that M. xanthus's gliding machinery senses environmental mechanical cues during force generation and modulates cell reversal accordingly. To examine our hypothesis, we expand an existing mathematical model for periodic polarity reversal in M. xanthus, incorporating the experimental data on the intracellular dynamics of the gliding machinery and the interaction between the gliding machinery and a key polarity regulator. The model successfully reproduces the dependence of cell reversal frequency on substrate stiffness observed in M. xanthus gliding. We further propose reversal control networks between the gliding and twitching motility machineries to explain the opposite reversal responses observed in wild type M. xanthus cells that possess both motility mechanisms. These results provide testable predictions for future experimental investigations. In conclusion, our model suggests that the gliding machinery in M. xanthus can function as a mechanosensor, which transduces mechanical cues into a cell reversal signal.
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Affiliation(s)
- Yirui Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Genetics, Bioinformatics and Computational Biology Graduate Program, Virginia Tech, Blacksburg, VA, United States
| | - Elias J. Topo
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, United States
- Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, United States
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, United States
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7
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Murphy P, Comstock J, Khan T, Zhang J, Welch R, Igoshin OA. Cell behaviors underlying Myxococcus xanthus aggregate dispersal. mSystems 2023; 8:e0042523. [PMID: 37747885 PMCID: PMC10654071 DOI: 10.1128/msystems.00425-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/27/2023] [Indexed: 09/27/2023] Open
Abstract
IMPORTANCE Understanding the processes behind bacterial biofilm formation, maintenance, and dispersal is essential for addressing their effects on health and ecology. Within these multicellular communities, various cues can trigger differentiation into distinct cell types, allowing cells to adapt to their specific local environment. The soil bacterium Myxococcus xanthus forms biofilms in response to starvation, marked by cells aggregating into mounds. Some aggregates persist as spore-filled fruiting bodies, while others disperse after initial formation for unknown reasons. Here, we use a combination of cell tracking analysis and computational simulations to identify behaviors at the cellular level that contribute to aggregate dispersal. Our results suggest that cells in aggregates actively determine whether to disperse or persist and undergo a transition to sporulation based on a self-produced cue related to the aggregate size. Identifying these cues is an important step in understanding and potentially manipulating bacterial cell-fate decisions.
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Affiliation(s)
- Patrick Murphy
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Center for Theoretical Physical Biology, Rice University, Houston, Texas, USA
| | - Jessica Comstock
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Trosporsha Khan
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Jiangguo Zhang
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Center for Theoretical Physical Biology, Rice University, Houston, Texas, USA
| | - Roy Welch
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Oleg A. Igoshin
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Center for Theoretical Physical Biology, Rice University, Houston, Texas, USA
- Department of Chemistry, Rice University, Houston, Texas, USA
- Department of Biosciences, Rice University, Houston, Texas, USA
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8
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Zhu C, Zhou Y, Kang J, Yang H, Lin J, Fang B. Alkaline arginine promotes the gentamicin-mediated killing of drug-resistant Salmonella by increasing NADH concentration and proton motive force. Front Microbiol 2023; 14:1237825. [PMID: 37795291 PMCID: PMC10546041 DOI: 10.3389/fmicb.2023.1237825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 08/29/2023] [Indexed: 10/06/2023] Open
Abstract
Introduction Antimicrobial resistance, especially the development of multidrug-resistant strains, is an urgent public health threat. Antibiotic adjuvants have been shown to improve the treatment of resistant bacterial infections. Methods We verified that exogenous L-arginine promoted the killing effect of gentamicin against Salmonella in vitro and in vivo, and measured intracellular ATP, NADH, and PMF of bacteria. Gene expression was determined using real-time quantitative PCR. Results This study found that alkaline arginine significantly increased gentamicin, tobramycin, kanamycin, and apramycin-mediated killing of drug-resistant Salmonella, including multidrug-resistant strains. Mechanistic studies showed that exogenous arginine was shown to increase the proton motive force, increasing the uptake of gentamicin and ultimately inducing bacterial cell death. Furthermore, in mouse infection model, arginine effectively improved gentamicin activity against Salmonella typhimurium. Discussion These findings confirm that arginine is a highly effective and harmless aminoglycoside adjuvant and provide important evidence for its use in combination with antimicrobial agents to treat drug-resistant bacterial infections.
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Affiliation(s)
- Chunyang Zhu
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, China
| | - Yanhong Zhou
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, China
| | - Jian Kang
- School of Animal Science and Technology, Guangdong Polytechnic of Science and Trade, Guangzhou, China
| | - Heng Yang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, China
| | - Jinglin Lin
- School of Animal Science and Technology, Guangdong Polytechnic of Science and Trade, Guangzhou, China
| | - Binghu Fang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou, China
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou, China
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9
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Saggu SK, Nath A, Kumar S. Myxobacteria: biology and bioactive secondary metabolites. Res Microbiol 2023; 174:104079. [PMID: 37169232 DOI: 10.1016/j.resmic.2023.104079] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/22/2023] [Accepted: 05/04/2023] [Indexed: 05/13/2023]
Abstract
Myxobacteria are Gram-negative eubacteria and they thrive in a variety of habitats including soil rich in organic matter, rotting wood, animal dung and marine environment. Myxobacteria are a promising source of new compounds associated with diverse bioactive spectrum and unique mode of action. The genome information of myxobacteria has revealed many orphan biosynthetic pathways indicating that these bacteria can be the source of several novel natural products. In this review, we highlight the biology of myxobacteria with emphasis on their habitat, life cycle, isolation methods and enlist all the bioactive secondary metabolites purified till date and their mode of action.
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Affiliation(s)
- Sandeep Kaur Saggu
- Department of Biotechnology, Kanya Maha Vidyalaya, Jalandhar, Punjab, India - 144004.
| | - Amar Nath
- University Centre of Excellence in Research, Baba Farid University of Health Sciences, Faridkot, Punjab India 151203.
| | - Shiv Kumar
- Guru Gobind Singh Medical College, Baba Farid University of Health Sciences, Faridkot, Punjab India 151203.
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10
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Fiegna F, Pande S, Peitz H, Velicer GJ. Widespread density dependence of bacterial growth under acid stress. iScience 2023; 26:106952. [PMID: 37332671 PMCID: PMC10275722 DOI: 10.1016/j.isci.2023.106952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 01/27/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023] Open
Abstract
Many microbial phenotypes are density-dependent, including group-level phenotypes emerging from cooperation. However, surveys for the presence of a particular form of density dependence across diverse species are rare, as are direct tests for the Allee effect, i.e., positive density dependence of fitness. Here, we test for density-dependent growth under acid stress in five diverse bacterial species and find the Allee effect in all. Yet social protection from acid stress appears to have evolved by multiple mechanisms. In Myxococcus xanthus, a strong Allee effect is mediated by pH-regulated secretion of a diffusible molecule by high-density populations. In other species, growth from low density under acid stress was not enhanced by high-density supernatant. In M. xanthus, high cell density may promote predation on other microbes that metabolically acidify their environment, and acid-mediated density dependence may impact the evolution of fruiting-body development. More broadly, high density may protect most bacterial species against acid stress.
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Affiliation(s)
- Francesca Fiegna
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Samay Pande
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | | | - Gregory J. Velicer
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Department of Biology, Indiana University, Bloomington, IN, USA
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11
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Nandel V, Scadden J, Baker MAB. Ion-Powered Rotary Motors: Where Did They Come from and Where They Are Going? Int J Mol Sci 2023; 24:10601. [PMID: 37445779 PMCID: PMC10341847 DOI: 10.3390/ijms241310601] [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: 05/30/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Molecular motors are found in many living organisms. One such molecular machine, the ion-powered rotary motor (IRM), requires the movement of ions across a membrane against a concentration gradient to drive rotational movement. The bacterial flagellar motor (BFM) is an example of an IRM which relies on ion movement through the stator proteins to generate the rotation of the flagella. There are many ions which can be used by the BFM stators to power motility and different ions can be used by a single bacterium expressing multiple stator variants. The use of ancestral sequence reconstruction (ASR) and functional analysis of reconstructed stators shows promise for understanding how these proteins evolved and when the divergence in ion use may have occurred. In this review, we discuss extant BFM stators and the ions that power them as well as recent examples of the use of ASR to study ion-channel selectivity and how this might be applied to further study of the BFM stator complex.
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Affiliation(s)
| | | | - Matthew A. B. Baker
- School of Biotechnology and Biomolecular Sciences (BABS), University of New South Wales, Sydney, NSW 2033, Australia; (V.N.); (J.S.)
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12
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Dinet C, Mignot T. Unorthodox regulation of the MglA Ras-like GTPase controlling polarity in Myxococcus xanthus. FEBS Lett 2023; 597:850-864. [PMID: 36520515 DOI: 10.1002/1873-3468.14565] [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: 10/21/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Motile cells have developed a large array of molecular machineries to actively change their direction of movement in response to spatial cues from their environment. In this process, small GTPases act as molecular switches and work in tandem with regulators and sensors of their guanine nucleotide status (GAP, GEF, GDI and effectors) to dynamically polarize the cell and regulate its motility. In this review, we focus on Myxococcus xanthus as a model organism to elucidate the function of an atypical small Ras GTPase system in the control of directed cell motility. M. xanthus cells direct their motility by reversing their direction of movement through a mechanism involving the redirection of the motility apparatus to the opposite cell pole. The reversal frequency of moving M. xanthus cells is controlled by modular and interconnected protein networks linking the chemosensory-like frizzy (Frz) pathway - that transmits environmental signals - to the downstream Ras-like Mgl polarity control system - that comprises the Ras-like MglA GTPase protein and its regulators. Here, we discuss how variations in the GTPase interactome landscape underlie single-cell decisions and consequently, multicellular patterns.
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Affiliation(s)
- Céline Dinet
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, France
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13
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Islam ST, Jolivet NY, Cuzin C, Belgrave AM, My L, Fleuchot B, Faure LM, Mahanta U, Kezzo AA, Saïdi F, Sharma G, Fiche JB, Bratton BP, Herrou J, Nollmann M, Shaevitz JW, Durand E, Mignot T. Unmasking of the von Willebrand A-domain surface adhesin CglB at bacterial focal adhesions mediates myxobacterial gliding motility. SCIENCE ADVANCES 2023; 9:eabq0619. [PMID: 36812310 PMCID: PMC9946355 DOI: 10.1126/sciadv.abq0619] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
The predatory deltaproteobacterium Myxococcus xanthus uses a helically-trafficked motor at bacterial focal-adhesion (bFA) sites to power gliding motility. Using total internal reflection fluorescence and force microscopies, we identify the von Willebrand A domain-containing outer-membrane (OM) lipoprotein CglB as an essential substratum-coupling adhesin of the gliding transducer (Glt) machinery at bFAs. Biochemical and genetic analyses reveal that CglB localizes to the cell surface independently of the Glt apparatus; once there, it is recruited by the OM module of the gliding machinery, a heteroligomeric complex containing the integral OM β barrels GltA, GltB, and GltH, as well as the OM protein GltC and OM lipoprotein GltK. This Glt OM platform mediates the cell-surface accessibility and retention of CglB by the Glt apparatus. Together, these data suggest that the gliding complex promotes regulated surface exposure of CglB at bFAs, thus explaining the manner by which contractile forces exerted by inner-membrane motors are transduced across the cell envelope to the substratum.
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Affiliation(s)
- Salim T. Islam
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Nicolas Y. Jolivet
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Clémence Cuzin
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Akeisha M. Belgrave
- Integrated Sciences Program, Harrisburg University of Science and Technology, Harrisburg, PA 17101, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Laetitia My
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Betty Fleuchot
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Laura M. Faure
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Utkarsha Mahanta
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bengaluru-560100, Karnataka, India
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana-502284, India
| | - Ahmad A. Kezzo
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Fares Saïdi
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, QC H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Laval, QC G1V 0A6, Canada
| | - Gaurav Sharma
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bengaluru-560100, Karnataka, India
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana-502284, India
| | - Jean-Bernard Fiche
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, 34090 Montpellier, France
| | - Benjamin P. Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN 37232, USA
| | - Julien Herrou
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Marcelo Nollmann
- Centre de Biochimie Structurale, CNRS UMR5048, INSERM U1054, 34090 Montpellier, France
| | - Joshua W. Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Eric Durand
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, CNRS - Université Aix-Marseille UMR7283, Institut de Microbiologie de la Méditerranée, 13009 Marseille, France
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14
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Shibata S, Tahara YO, Katayama E, Kawamoto A, Kato T, Zhu Y, Nakane D, Namba K, Miyata M, McBride MJ, Nakayama K. Filamentous structures in the cell envelope are associated with bacteroidetes gliding machinery. Commun Biol 2023; 6:94. [PMID: 36690840 PMCID: PMC9870892 DOI: 10.1038/s42003-023-04472-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/12/2023] [Indexed: 01/24/2023] Open
Abstract
Many bacteria belonging to the phylum Bacteroidetes move on solid surfaces, called gliding motility. In our previous study with the Bacteroidetes gliding bacterium Flavobacterium johnsoniae, we proposed a helical loop track model, where adhesive SprB filaments are propelled along a helical loop on the cell surface. In this study, we observed the gliding cell rotating counterclockwise about its axis when viewed from the rear to the advancing direction of the cell and revealed that one labeled SprB focus sometimes overtook and passed another SprB focus that was moving in the same direction. Several electron microscopic analyses revealed the presence of a possible multi-rail structure underneath the outer membrane, which was associated with SprB filaments and contained GldJ protein. These results provide insights into the mechanism of Bacteroidetes gliding motility, in which the SprB filaments are propelled along tracks that may form a multi-rail system underneath the outer membrane. The insights may give clues as to how the SprB filaments get their driving force.
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Affiliation(s)
- Satoshi Shibata
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
- Division of Bacteriology, Department of Microbiology and Immunology, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan.
| | - Yuhei O Tahara
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Graduate School of Science, Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
| | - Eisaku Katayama
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Waseda Research Institute for Science and Engineering, Okubo Shinjyuku, Tokyo, Japan
| | - Akihiro Kawamoto
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Takayuki Kato
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Yongtao Zhu
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201, USA
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, China
| | - Daisuke Nakane
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Makoto Miyata
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
- Graduate School of Science, Osaka Metropolitan University, Sumiyoshi-ku, Osaka, Japan
| | - Mark J McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, 53201, USA
| | - Koji Nakayama
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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15
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Carreira LAM, Szadkowski D, Müller F, Søgaard-Andersen L. Spatiotemporal regulation of switching front–rear cell polarity. Curr Opin Cell Biol 2022; 76:102076. [DOI: 10.1016/j.ceb.2022.102076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 11/30/2022]
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16
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Production of 3′,3′-cGAMP by a Bdellovibrio bacteriovorus promiscuous GGDEF enzyme, Bd0367, regulates exit from prey by gliding motility. PLoS Genet 2022; 18:e1010164. [PMID: 35622882 PMCID: PMC9140294 DOI: 10.1371/journal.pgen.1010164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 03/24/2022] [Indexed: 11/23/2022] Open
Abstract
Bacterial second messengers are important for regulating diverse bacterial lifestyles. Cyclic di-GMP (c-di-GMP) is produced by diguanylate cyclase enzymes, named GGDEF proteins, which are widespread across bacteria. Recently, hybrid promiscuous (Hypr) GGDEF proteins have been described in some bacteria, which produce both c-di-GMP and a more recently identified bacterial second messenger, 3′,3′-cyclic-GMP-AMP (cGAMP). One of these proteins was found in the predatory Bdellovibrio bacteriovorus, Bd0367. The bd0367 GGDEF gene deletion strain was found to enter prey cells, but was incapable of leaving exhausted prey remnants via gliding motility on a solid surface once predator cell division was complete. However, it was unclear which signal regulated this process. We show that cGAMP signalling is active within B. bacteriovorus and that, in addition to producing c-di-GMP and some c-di-AMP, Bd0367 is a primary producer of cGAMP in vivo. Site-directed mutagenesis of serine 214 to an aspartate rendered Bd0367 into primarily a c-di-GMP synthase. B. bacteriovorus strain bd0367S214D phenocopies the bd0367 deletion strain by being unable to glide on a solid surface, leading to an inability of new progeny to exit from prey cells post-replication. Thus, this process is regulated by cGAMP. Deletion of bd0367 was also found to be incompatible with wild-type flagellar biogenesis, as a result of an acquired mutation in flagellin chaperone gene homologue fliS, implicating c-di-GMP in regulation of swimming motility. Thus the single Bd0367 enzyme produces two secondary messengers by action of the same GGDEF domain, the first reported example of a synthase that regulates multiple second messengers in vivo. Unlike roles of these signalling molecules in other bacteria, these signal to two separate motility systems, gliding and flagellar, which are essential for completion of the bacterial predation cycle and prey exit by B. bacteriovorus. Secondary messengers are important signalling molecules in bacteria and a recently discovered one, called cGAMP, has recently been shown to be made by some enzymes which had previously been known to produce another secondary messenger, c-di-GMP. One of these “hybrid promiscuous” enzymes (Bd0367) is found in Bdellovibrio bacteriovorus, a bacterium that preys upon other bacteria, burrowing inside them and consuming them from within. Previous gene deletion work had shown that Bd0367 was essential in signalling for Bdellovibrio to leave the remains of its prey cell by gliding motility after predation was complete and it was thought that this was due to c-di-GMP signalling. However, here, we show that this gliding motility is actually regulated by cGAMP signalling and that c-di-GMP signalling is involved in swimming motility. A single enzyme produces two different molecules, signalling to two discrete motility systems, both of which are required for successful completion of the bacterium’s predatory lifestyle in prey on solid surfaces or in liquids.
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17
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Chen J, Nan B. Flagellar Motor Transformed: Biophysical Perspectives of the Myxococcus xanthus Gliding Mechanism. Front Microbiol 2022; 13:891694. [PMID: 35602090 PMCID: PMC9120999 DOI: 10.3389/fmicb.2022.891694] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Many bacteria move on solid surfaces using gliding motility, without involvement of flagella or pili. Gliding of Myxococcus xanthus is powered by a proton channel homologous to the stators in the bacterial flagellar motor. Instead of being fixed in place and driving the rotation of a circular protein track like the flagellar basal body, the gliding machinery of M. xanthus travels the length of the cell along helical trajectories, while mechanically engaging with the substrate. Such movement entails a different molecular mechanism to generate propulsion on the cell. In this perspective, we will discuss the similarities and differences between the M. xanthus gliding machinery and bacterial flagellar motor, and use biophysical principles to generate hypotheses about the operating mechanism, efficiency, sensitivity to control, and mechanosensing of M. xanthus gliding.
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Affiliation(s)
- Jing Chen
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX, United States
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18
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Subedi K, Wall D. Conditional and Synthetic Type IV Pili-Dependent Motility Phenotypes in Myxococcus xanthus. Front Microbiol 2022; 13:879090. [PMID: 35586861 PMCID: PMC9108774 DOI: 10.3389/fmicb.2022.879090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/12/2022] [Indexed: 12/02/2022] Open
Abstract
Myxobacteria exhibit a variety of complex social behaviors that all depend on coordinated movement of cells on solid surfaces. The cooperative nature of cell movements is known as social (S)-motility. This system is powered by cycles of type IV pili (Tfp) extension and retraction. Exopolysaccharide (EPS) also serves as a matrix to hold cells together. Here, we characterized a new S-motility gene in Myxococcus xanthus. This mutant is temperature-sensitive (Ts–) for S-motility; however, Tfp and EPS are made. A 1 bp deletion was mapped to the MXAN_4099 locus and the gene was named sglS. Null mutations in sglS exhibit a synthetic enhanced phenotype with a null sglT mutation, a previously characterized S-motility gene that exhibits a similar Ts– phenotype. Our results suggest that SglS and SglT contribute toward Tfp function at high temperatures in redundant pathways. However, at low temperatures only one pathway is necessary for wild-type S-motility, while in the double mutant, motility is nearly abolished at low temperatures. Interestingly, the few cells that do move do so with a high reversal frequency. We suggest SglS and SglT play conditional roles facilitating Tfp retraction and hence motility in M. xanthus.
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Affiliation(s)
- Kalpana Subedi
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
- Department of Chemistry, University of Wyoming, Laramie, WY, United States
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
- *Correspondence: Daniel Wall,
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19
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Asp ME, Ho Thanh MT, Germann DA, Carroll RJ, Franceski A, Welch RD, Gopinath A, Patteson AE. Spreading rates of bacterial colonies depend on substrate stiffness and permeability. PNAS NEXUS 2022; 1:pgac025. [PMID: 36712798 PMCID: PMC9802340 DOI: 10.1093/pnasnexus/pgac025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/25/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023]
Abstract
The ability of bacteria to colonize and grow on different surfaces is an essential process for biofilm development. Here, we report the use of synthetic hydrogels with tunable stiffness and porosity to assess physical effects of the substrate on biofilm development. Using time-lapse microscopy to track the growth of expanding Serratia marcescens colonies, we find that biofilm colony growth can increase with increasing substrate stiffness, unlike what is found on traditional agar substrates. Using traction force microscopy-based techniques, we find that biofilms exert transient stresses correlated over length scales much larger than a single bacterium, and that the magnitude of these forces also increases with increasing substrate stiffness. Our results are consistent with a model of biofilm development in which the interplay between osmotic pressure arising from the biofilm and the poroelastic response of the underlying substrate controls biofilm growth and morphology.
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Affiliation(s)
- Merrill E Asp
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Minh-Tri Ho Thanh
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Danielle A Germann
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Robert J Carroll
- Physics Department, Syracuse University, Syracuse, NY 13244, USA,BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Alana Franceski
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA,Biology Department, Syracuse University, Syracuse, NY 13244, USA
| | - Roy D Welch
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA,Biology Department, Syracuse University, Syracuse, NY 13244, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA,Health Sciences Research Institute, University of California, Merced, Merced, CA 95343, USA
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20
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Yeow J, Chng SS. Of zones, bridges and chaperones - phospholipid transport in bacterial outer membrane assembly and homeostasis. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35384832 DOI: 10.1099/mic.0.001177] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The outer membrane (OM) is a formidable permeability barrier that protects Gram-negative bacteria from detergents and antibiotics. It possesses exquisite lipid asymmetry, requiring the placement and retention of lipopolysaccharides (LPS) in the outer leaflet, and phospholipids (PLs) in the inner leaflet. To establish OM lipid asymmetry, LPS are transported from the inner membrane (IM) directly to the outer leaflet of the OM. In contrast, mechanisms for PL trafficking across the cell envelope are much less understood. In this review, we summarize and discuss recent advances in our understanding of PL transport, making parallel comparisons to well-established pathways for OM lipoprotein (Lol) and LPS (Lpt). Insights into putative PL transport systems highlight possible connections back to the 'Bayer bridges', adhesion zones between the IM and the OM that had been observed more than 50 years ago, and proposed as passages for export of OM components, including LPS and PLs.
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Affiliation(s)
- Jiang Yeow
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
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21
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Vincent MS, Comas Hervada C, Sebban-Kreuzer C, Le Guenno H, Chabalier M, Kosta A, Guerlesquin F, Mignot T, McBride MJ, Cascales E, Doan T. Dynamic proton-dependent motors power type IX secretion and gliding motility in Flavobacterium. PLoS Biol 2022; 20:e3001443. [PMID: 35333857 PMCID: PMC8986121 DOI: 10.1371/journal.pbio.3001443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/06/2022] [Accepted: 03/01/2022] [Indexed: 02/06/2023] Open
Abstract
Motile bacteria usually rely on external apparatus like flagella for swimming or pili for twitching. By contrast, gliding bacteria do not rely on obvious surface appendages to move on solid surfaces. Flavobacterium johnsoniae and other bacteria in the Bacteroidetes phylum use adhesins whose movement on the cell surface supports motility. In F. johnsoniae, secretion and helicoidal motion of the main adhesin SprB are intimately linked and depend on the type IX secretion system (T9SS). Both processes necessitate the proton motive force (PMF), which is thought to fuel a molecular motor that comprises the GldL and GldM cytoplasmic membrane proteins. Here, we show that F. johnsoniae gliding motility is powered by the pH gradient component of the PMF. We further delineate the interaction network between the GldLM transmembrane helices (TMHs) and show that conserved glutamate residues in GldL TMH2 are essential for gliding motility, although having distinct roles in SprB secretion and motion. We then demonstrate that the PMF and GldL trigger conformational changes in the GldM periplasmic domain. We finally show that multiple GldLM complexes are distributed in the membrane, suggesting that a network of motors may be present to move SprB along a helical path on the cell surface. Altogether, our results provide evidence that GldL and GldM assemble dynamic membrane channels that use the proton gradient to power both T9SS-dependent secretion of SprB and its motion at the cell surface.
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Affiliation(s)
- Maxence S. Vincent
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Caterina Comas Hervada
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Corinne Sebban-Kreuzer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Maïalène Chabalier
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Artemis Kosta
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Françoise Guerlesquin
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7283, Marseille, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Eric Cascales
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Thierry Doan
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
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22
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A noncanonical cytochrome c stimulates calcium binding by PilY1 for type IVa pili formation. Proc Natl Acad Sci U S A 2022; 119:2115061119. [PMID: 35121662 PMCID: PMC8833165 DOI: 10.1073/pnas.2115061119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2021] [Indexed: 12/23/2022] Open
Abstract
Type IVa pili (T4aP) are versatile bacterial cell surface structures that undergo extension/adhesion/retraction cycles powered by the cell envelope-spanning T4aP machine. In this machine, a complex composed of four minor pilins and PilY1 primes T4aP extension and is also present at the pilus tip mediating adhesion. Similar to many several other bacteria, Myxococcus xanthus contains multiple minor pilins/PilY1 sets that are incompletely understood. Here, we report that minor pilins and PilY1 (PilY1.1) of cluster_1 form priming and tip complexes contingent on calcium and a noncanonical cytochrome c (TfcP) with an unusual His/Cys heme ligation. We provide evidence that TfcP is unlikely to participate in electron transport and instead stimulates calcium binding by PilY1.1 at low-calcium concentrations, thereby stabilizing PilY1.1 and enabling T4aP function in a broader range of calcium concentrations. These results not only identify a previously undescribed function of cytochromes c but also illustrate how incorporation of an accessory factor expands the environmental range under which the T4aP system functions.
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23
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Rieu M, Krutyholowa R, Taylor NMI, Berry RM. A new class of biological ion-driven rotary molecular motors with 5:2 symmetry. Front Microbiol 2022; 13:948383. [PMID: 35992645 PMCID: PMC9389320 DOI: 10.3389/fmicb.2022.948383] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Several new structures of three types of protein complexes, obtained by cryo-electron microscopy (cryo-EM) and published between 2019 and 2021, identify a new family of natural molecular wheels, the "5:2 rotary motors." These span the cytoplasmic membranes of bacteria, and their rotation is driven by ion flow into the cell. They consist of a pentameric wheel encircling a dimeric axle within the cytoplasmic membrane of both Gram-positive and gram-negative bacteria. The axles extend into the periplasm, and the wheels extend into the cytoplasm. Rotation of these wheels has never been observed directly; it is inferred from the symmetry of the complexes and from the roles they play within the larger systems that they are known to power. In particular, the new structure of the stator complex of the Bacterial Flagellar Motor, MotA5B2, is consistent with a "wheels within wheels" model of the motor. Other 5:2 rotary motors are believed to share the core rotary function and mechanism, driven by ion-motive force at the cytoplasmic membrane. Their structures diverge in their periplasmic and cytoplasmic parts, reflecting the variety of roles that they perform. This review focuses on the structures of 5:2 rotary motors and their proposed mechanisms and functions. We also discuss molecular rotation in general and its relation to the rotational symmetry of molecular complexes.
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Affiliation(s)
- Martin Rieu
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
| | - Roscislaw Krutyholowa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nicholas M. I. Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Nicholas M. I. Taylor,
| | - Richard M. Berry
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
- *Correspondence: Richard M. Berry,
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Abstract
A wide range of biological systems, from microbial swarms to bird flocks, display emergent behaviors driven by coordinated movement of individuals. To this end, individual organisms interact by recognizing their kin and adjusting their motility based on others around them. However, even in the best-studied systems, the mechanistic basis of the interplay between kin recognition and motility coordination is not understood. Here, using a combination of experiments and mathematical modeling, we uncover the mechanism of an emergent social behavior in Myxococcus xanthus. By overexpressing the cell surface adhesins TraA and TraB, which are involved in kin recognition, large numbers of cells adhere to one another and form organized macroscopic circular aggregates that spin clockwise or counterclockwise. Mechanistically, TraAB adhesion results in sustained cell-cell contacts that trigger cells to suppress cell reversals, and circular aggregates form as the result of cells’ ability to follow their own cellular slime trails. Furthermore, our in silico simulations demonstrate a remarkable ability to predict self-organization patterns when phenotypically distinct strains are mixed. For example, defying naive expectations, both models and experiments found that strains engineered to overexpress different and incompatible TraAB adhesins nevertheless form mixed circular aggregates. Therefore, this work provides key mechanistic insights into M. xanthus social interactions and demonstrates how local cell contacts induce emergent collective behaviors by millions of cells. IMPORTANCE In many species, large populations exhibit emergent behaviors whereby all related individuals move in unison. For example, fish in schools can all dart in one direction simultaneously to avoid a predator. Currently, it is impossible to explain how such animals recognize kin through brain cognition and elicit such behaviors at a molecular level. However, microbes also recognize kin and exhibit emergent collective behaviors that are experimentally tractable. Here, using a model social bacterium, we engineer dispersed individuals to organize into synchronized collectives that create emergent patterns. With experimental and mathematical approaches, we explain how this occurs at both molecular and population levels. The results demonstrate how the combination of local physical interactions triggers intracellular signaling, which in turn leads to emergent behaviors on a population scale.
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25
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Abstract
Bacteria have developed a large array of motility mechanisms to exploit available resources and environments. These mechanisms can be broadly classified into swimming in aqueous media and movement over solid surfaces. Swimming motility involves either the rotation of rigid helical filaments through the external medium or gyration of the cell body in response to the rotation of internal filaments. On surfaces, bacteria swarm collectively in a thin layer of fluid powered by the rotation of rigid helical filaments, they twitch by assembling and disassembling type IV pili, they glide by driving adhesins along tracks fixed to the cell surface and, finally, non-motile cells slide over surfaces in response to outward forces due to colony growth. Recent technological advances, especially in cryo-electron microscopy, have greatly improved our knowledge of the molecular machinery that powers the various forms of bacterial motility. In this Review, we describe the current understanding of the physical and molecular mechanisms that allow bacteria to move around.
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26
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Seef S, Herrou J, de Boissier P, My L, Brasseur G, Robert D, Jain R, Mercier R, Cascales E, Habermann BH, Mignot T. A Tad-like apparatus is required for contact-dependent prey killing in predatory social bacteria. eLife 2021; 10:72409. [PMID: 34505573 PMCID: PMC8460266 DOI: 10.7554/elife.72409] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/09/2021] [Indexed: 12/21/2022] Open
Abstract
Myxococcus xanthus, a soil bacterium, predates collectively using motility to invade prey colonies. Prey lysis is mostly thought to rely on secreted factors, cocktails of antibiotics and enzymes, and direct contact with Myxococcus cells. In this study, we show that on surfaces the coupling of A-motility and contact-dependent killing is the central predatory mechanism driving effective prey colony invasion and consumption. At the molecular level, contact-dependent killing involves a newly discovered type IV filament-like machinery (Kil) that both promotes motility arrest and prey cell plasmolysis. In this process, Kil proteins assemble at the predator-prey contact site, suggesting that they allow tight contact with prey cells for their intoxication. Kil-like systems form a new class of Tad-like machineries in predatory bacteria, suggesting a conserved function in predator-prey interactions. This study further reveals a novel cell-cell interaction function for bacterial pili-like assemblages.
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Affiliation(s)
- Sofiene Seef
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Julien Herrou
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Paul de Boissier
- Aix-Marseille Université - CNRS UMR 7288, Institut de Biologie du Développement de Marseille and Turing Center for Living Systems, Marseille, France
| | - Laetitia My
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Gael Brasseur
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Donovan Robert
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Rikesh Jain
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France.,Aix-Marseille Université - CNRS UMR 7288, Institut de Biologie du Développement de Marseille and Turing Center for Living Systems, Marseille, France
| | - Romain Mercier
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
| | - Eric Cascales
- Aix-Marseille Université - CNRS UMR 7255, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Bianca H Habermann
- Aix-Marseille Université - CNRS UMR 7288, Institut de Biologie du Développement de Marseille and Turing Center for Living Systems, Marseille, France
| | - Tâm Mignot
- Aix-Marseille Université - CNRS UMR 7283, Institut de Microbiologie de la Méditerranée and Turing Center for Living Systems, Marseille, France
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Das S, Vera M, Gandin V, Singer RH, Tutucci E. Intracellular mRNA transport and localized translation. Nat Rev Mol Cell Biol 2021; 22:483-504. [PMID: 33837370 PMCID: PMC9346928 DOI: 10.1038/s41580-021-00356-8] [Citation(s) in RCA: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2021] [Indexed: 02/08/2023]
Abstract
Fine-tuning cellular physiology in response to intracellular and environmental cues requires precise temporal and spatial control of gene expression. High-resolution imaging technologies to detect mRNAs and their translation state have revealed that all living organisms localize mRNAs in subcellular compartments and create translation hotspots, enabling cells to tune gene expression locally. Therefore, mRNA localization is a conserved and integral part of gene expression regulation from prokaryotic to eukaryotic cells. In this Review, we discuss the mechanisms of mRNA transport and local mRNA translation across the kingdoms of life and at organellar, subcellular and multicellular resolution. We also discuss the properties of messenger ribonucleoprotein and higher order RNA granules and how they may influence mRNA transport and local protein synthesis. Finally, we summarize the technological developments that allow us to study mRNA localization and local translation through the simultaneous detection of mRNAs and proteins in single cells, mRNA and nascent protein single-molecule imaging, and bulk RNA and protein detection methods.
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Affiliation(s)
- Sulagna Das
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY, USA.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA
| | - Maria Vera
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | | | - Robert H. Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY, USA.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA.,Janelia Research Campus of the HHMI, Ashburn, VA, USA.,;
| | - Evelina Tutucci
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,;
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Three PilZ Domain Proteins, PlpA, PixA, and PixB, Have Distinct Functions in Regulation of Motility and Development in Myxococcus xanthus. J Bacteriol 2021; 203:e0012621. [PMID: 33875546 PMCID: PMC8316039 DOI: 10.1128/jb.00126-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In bacteria, the nucleotide-based second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) binds to effectors to generate outputs in response to changes in the environment. In Myxococcus xanthus, c-di-GMP regulates type IV pilus-dependent motility and the starvation-induced developmental program that results in formation of spore-filled fruiting bodies; however, little is known about the effectors that bind c-di-GMP. Here, we systematically inactivated all 24 genes encoding PilZ domain-containing proteins, which are among the most common c-di-GMP effectors. We confirm that the stand-alone PilZ domain protein PlpA is important for regulation of motility independently of the Frz chemosensory system and that Pkn1, which is composed of a Ser/Thr kinase domain and a PilZ domain, is specifically important for development. Moreover, we identify two PilZ domain proteins that have distinct functions in regulating motility and development. PixB, which is composed of two PilZ domains and an acetyltransferase domain, binds c-di-GMP in vitro and regulates type IV pilus-dependent and gliding motility in a Frz-dependent manner as well as development. The acetyltransferase domain is required and sufficient for function during growth, while all three domains and c-di-GMP binding are essential for PixB function during development. PixA is a response regulator composed of a PilZ domain and a receiver domain, binds c-di-GMP in vitro, and regulates motility independently of the Frz system, likely by setting up the polarity of the two motility systems. Our results support a model whereby PlpA, PixA, and PixB act in independent pathways and have distinct functions in regulation of motility. IMPORTANCE c-di-GMP signaling controls bacterial motility in many bacterial species by binding to downstream effector proteins. Here, we identify two PilZ domain-containing proteins in Myxococcus xanthus that bind c-di-GMP. We show that PixB, which contains two PilZ domains and an acetyltransferase domain, acts in a manner that depends on the Frz chemosensory system to regulate motility via the acetyltransferase domain, while the intact protein and c-di-GMP binding are essential for PixB to support development. In contrast, PixA acts in a Frz-independent manner to regulate motility. Taking our results together with previous observations, we conclude that PilZ domain proteins and c-di-GMP act in multiple independent pathways to regulate motility and development in M. xanthus.
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29
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Kapoor S, Kodesia A, Kalidas N, Ashish, Thakur KG. Structural characterization of Myxococcus xanthus MglC, a component of the polarity control system, and its interactions with its paralog MglB. J Biol Chem 2021; 296:100308. [PMID: 33493516 PMCID: PMC7949163 DOI: 10.1016/j.jbc.2021.100308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 11/28/2022] Open
Abstract
The δ-proteobacteria Myxococcus xanthus displays social (S) and adventurous (A) motilities, which require pole-to-pole reversal of the motility regulator proteins. Mutual gliding motility protein C (MglC), a paralog of GTPase-activating protein Mutual gliding motility protein B (MglB), is a member of the polarity module involved in regulating motility. However, little is known about the structure and function of MglC. Here, we determined ∼1.85 Å resolution crystal structure of MglC using Selenomethionine Single-wavelength anomalous diffraction. The crystal structure revealed that, despite sharing <9% sequence identity, both MglB and MglC adopt a Regulatory Light Chain 7 family fold. However, MglC has a distinct ∼30° to 40° shift in the orientation of the functionally important α2 helix compared with other structural homologs. Using isothermal titration calorimetry and size-exclusion chromatography, we show that MglC binds MglB in 2:4 stoichiometry with submicromolar range dissociation constant. Using small-angle X-ray scattering and molecular docking studies, we show that the MglBC complex consists of a MglC homodimer sandwiched between two homodimers of MglB. A combination of size-exclusion chromatography and site-directed mutagenesis studies confirmed the MglBC interacting interface obtained by molecular docking studies. Finally, we show that the C-terminal region of MglB, crucial for binding its established partner MglA, is not required for binding MglC. These studies suggest that the MglB uses distinct interfaces to bind MglA and MglC. Based on these data, we propose a model suggesting a new role for MglC in polarity reversal in M. xanthus.
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Affiliation(s)
- Srajan Kapoor
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Akriti Kodesia
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Nidhi Kalidas
- Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Ashish
- Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, Council of Scientific and Industrial Research-Institute of Microbial Technology, G. N. Ramachandran Protein Centre, Chandigarh, India.
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30
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Treuner-Lange A, Chang YW, Glatter T, Herfurth M, Lindow S, Chreifi G, Jensen GJ, Søgaard-Andersen L. PilY1 and minor pilins form a complex priming the type IVa pilus in Myxococcus xanthus. Nat Commun 2020; 11:5054. [PMID: 33028835 PMCID: PMC7541494 DOI: 10.1038/s41467-020-18803-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 09/14/2020] [Indexed: 01/05/2023] Open
Abstract
Type IVa pili are ubiquitous and versatile bacterial cell surface filaments that undergo cycles of extension, adhesion and retraction powered by the cell-envelope spanning type IVa pilus machine (T4aPM). The overall architecture of the T4aPM and the location of 10 conserved core proteins within this architecture have been elucidated. Here, using genetics, cell biology, proteomics and cryo-electron tomography, we demonstrate that the PilY1 protein and four minor pilins, which are widely conserved in T4aP systems, are essential for pilus extension in Myxococcus xanthus and form a complex that is an integral part of the T4aPM. Moreover, these proteins are part of the extended pilus. Our data support a model whereby the PilY1/minor pilin complex functions as a priming complex in T4aPM for pilus extension, a tip complex in the extended pilus for adhesion, and a cork for terminating retraction to maintain a priming complex for the next round of extension.
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Affiliation(s)
- Anke Treuner-Lange
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 422 Curie Boulevard, Philadelphia, PA, 19104, USA
| | - Timo Glatter
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Marco Herfurth
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Steffi Lindow
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Georges Chreifi
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Lotte Søgaard-Andersen
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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Santiveri M, Roa-Eguiara A, Kühne C, Wadhwa N, Hu H, Berg HC, Erhardt M, Taylor NM. Structure and Function of Stator Units of the Bacterial Flagellar Motor. Cell 2020; 183:244-257.e16. [DOI: 10.1016/j.cell.2020.08.016] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/09/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022]
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The small GTPase MglA together with the TPR domain protein SgmX stimulates type IV pili formation in M. xanthus. Proc Natl Acad Sci U S A 2020; 117:23859-23868. [PMID: 32900945 PMCID: PMC7519303 DOI: 10.1073/pnas.2004722117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many bacteria move across surfaces using type IV pili (T4P). The piliation pattern varies between species; however, the underlying mechanisms governing these patterns remain largely unknown. Here, we demonstrate that in the rod-shaped Myxococcus xanthus cells, the unipolar formation of T4P at the leading cell pole is the result of stimulation by the small GTPase MglA together with the effector protein SgmX, while MglB, the cognate MglA GTPase activating protein (GAP) that localizes to the lagging cell pole, blocks this stimulation at the lagging pole due to its GAP activity. During reversals, MglA/SgmX and MglB switch polarity, laying the foundation for T4P formation at the new leading cell pole and inhibition of T4P formation at the former leading cell pole. Bacteria can move across surfaces using type IV pili (T4P), which undergo cycles of extension, adhesion, and retraction. The T4P localization pattern varies between species; however, the underlying mechanisms are largely unknown. In the rod-shaped Myxococcus xanthus cells, T4P localize at the leading cell pole. As cells reverse their direction of movement, T4P are disassembled at the old leading pole and then form at the new leading pole. Thus, cells can form T4P at both poles but engage only one pole at a time in T4P formation. Here, we address how this T4P unipolarity is realized. We demonstrate that the small Ras-like GTPase MglA stimulates T4P formation in its GTP-bound state by direct interaction with the tetratricopeptide repeat (TPR) domain-containing protein SgmX. SgmX, in turn, is important for polar localization of the T4P extension ATPase PilB. The cognate MglA GTPase activating protein (GAP) MglB, which localizes mainly to the lagging cell pole, indirectly blocks T4P formation at this pole by stimulating the conversion of MglA-GTP to MglA-GDP. Based on these findings, we propose a model whereby T4P unipolarity is accomplished by stimulation of T4P formation at the leading pole by MglA-GTP and SgmX and indirect inhibition of T4P formation at the lagging pole by MglB due to its MglA GAP activity. During reversals, MglA, SgmX, and MglB switch polarity, thus laying the foundation for T4P formation at the new leading pole and inhibition of T4P formation at the new lagging pole.
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Characterization of the Exopolysaccharide Biosynthesis Pathway in Myxococcus xanthus. J Bacteriol 2020; 202:JB.00335-20. [PMID: 32778557 PMCID: PMC7484181 DOI: 10.1128/jb.00335-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/16/2020] [Indexed: 11/20/2022] Open
Abstract
The secreted polysaccharide referred to as exopolysaccharide (EPS) has important functions in the social life cycle of M. xanthus; however, little is known about how EPS is synthesized. Here, we characterized the EPS biosynthetic machinery and showed that it makes up a Wzx/Wzy-dependent pathway for polysaccharide biosynthesis. Mutants lacking a component of this pathway had reduced type IV pilus-dependent motility and a conditional defect in development. These analyses also suggest that EPS and/or the EPS biosynthetic machinery is important for type IV pilus formation. Myxococcus xanthus arranges into two morphologically distinct biofilms depending on its nutritional status, i.e., coordinately spreading colonies in the presence of nutrients and spore-filled fruiting bodies in the absence of nutrients. A secreted polysaccharide, referred to as exopolysaccharide (EPS), is a structural component of both biofilms and is also important for type IV pilus-dependent motility and fruiting body formation. Here, we characterize the biosynthetic machinery responsible for EPS biosynthesis using bioinformatics, genetics, heterologous expression, and biochemical experiments. We show that this machinery constitutes a Wzx/Wzy-dependent pathway dedicated to EPS biosynthesis. Our data support that EpsZ (MXAN_7415) is the polyisoprenyl-phosphate hexose-1-phosphate transferase responsible for the initiation of the repeat unit synthesis. Heterologous expression experiments support that EpsZ has galactose-1-P transferase activity. Moreover, MXAN_7416, renamed WzxEPS, and MXAN_7442, renamed WzyEPS, are the Wzx flippase and Wzy polymerase responsible for translocation and polymerization of the EPS repeat unit, respectively. In this pathway, EpsV (MXAN_7421) also is the polysaccharide copolymerase and EpsY (MXAN_7417) the outer membrane polysaccharide export (OPX) protein. Mutants with single in-frame deletions in the five corresponding genes had defects in type IV pilus-dependent motility and a conditional defect in fruiting body formation. Furthermore, all five mutants were deficient in type IV pilus formation, and genetic analyses suggest that EPS and/or the EPS biosynthetic machinery stimulates type IV pilus extension. Additionally, we identify a polysaccharide biosynthesis gene cluster, which together with an orphan gene encoding an OPX protein make up a complete Wzx/Wzy-dependent pathway for synthesis of an unknown polysaccharide. IMPORTANCE The secreted polysaccharide referred to as exopolysaccharide (EPS) has important functions in the social life cycle of M. xanthus; however, little is known about how EPS is synthesized. Here, we characterized the EPS biosynthetic machinery and showed that it makes up a Wzx/Wzy-dependent pathway for polysaccharide biosynthesis. Mutants lacking a component of this pathway had reduced type IV pilus-dependent motility and a conditional defect in development. These analyses also suggest that EPS and/or the EPS biosynthetic machinery is important for type IV pilus formation.
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Cao P, Wall D. The Fluidity of the Bacterial Outer Membrane Is Species Specific: Bacterial Lifestyles and the Emergence of a Fluid Outer Membrane. Bioessays 2020; 42:e1900246. [PMID: 32363627 PMCID: PMC7392792 DOI: 10.1002/bies.201900246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/23/2020] [Indexed: 01/17/2023]
Abstract
The outer membrane (OM) is an essential barrier that guards Gram-negative bacteria from diverse environmental insults. Besides functioning as a chemical gatekeeper, the OM also contributes towards the strength and stiffness of cells and allows them to sustain mechanical stress. Largely influenced by studies of Escherichia coli, the OM is viewed as a rigid barrier where OM proteins and lipopolysaccharides display restricted mobility. Here the discussion is extended to other bacterial species, with a focus on Myxococcus xanthus. In contrast to the rigid OM paradigm, myxobacteria possess a relatively fluid OM. It is concluded that the fluidity of the OM varies across environmental species, which is likely linked to their evolution and adaptation to specific ecological niches. Importantly, a fluid OM can endow bacteria with distinct functions for cell-cell and cell-environment interactions.
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Affiliation(s)
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, 1000 E University Avenue, Laramie, WY, 82071, USA
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35
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Rueangkham N, Estabrook ID, Hawkins RJ. Modelling cytoskeletal transport by clusters of non-processive molecular motors with limited binding sites. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200527. [PMID: 32968517 PMCID: PMC7481682 DOI: 10.1098/rsos.200527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Molecular motors are responsible for intracellular transport of a variety of biological cargo. We consider the collective behaviour of a finite number of motors attached on a cargo. We extend previous analytical work on processive motors to the case of non-processive motors, which stochastically bind on and off cytoskeletal filaments with a limited number of binding sites available. Physically, motors attached to a cargo cannot bind anywhere along the filaments, so the number of accessible binding sites on the filament should be limited. Thus, we analytically study the distribution and the velocity of a cluster of non-processive motors with limited number of binding sites. To validate our analytical results and to go beyond the level of detail possible analytically, we perform Monte Carlo latticed based stochastic simulations. In particular, in our simulations, we include sequence preservation of motors performing stepping and binding obeying a simple exclusion process. We find that limiting the number of binding sites reduces the probability of non-processive motors binding but has a relatively small effect on force-velocity relations. Our analytical and stochastic simulation results compare well to published data from in vitro and in vivo experiments.
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36
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Carreira LAM, Tostevin F, Gerland U, Søgaard-Andersen L. Protein-protein interaction network controlling establishment and maintenance of switchable cell polarity. PLoS Genet 2020; 16:e1008877. [PMID: 32569324 PMCID: PMC7332107 DOI: 10.1371/journal.pgen.1008877] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/02/2020] [Accepted: 05/21/2020] [Indexed: 11/19/2022] Open
Abstract
Cell polarity underlies key processes in all cells, including growth, differentiation and division. In the bacterium Myxococcus xanthus, front-rear polarity is crucial for motility. Notably, this polarity can be inverted, independent of the cell-cycle, by chemotactic signaling. However, a precise understanding of the protein network that establishes polarity and allows for its inversion has remained elusive. Here, we use a combination of quantitative experiments and data-driven theory to unravel the complex interplay between the three key components of the M. xanthus polarity module. By studying each of these components in isolation and their effects as we systematically reconstruct the system, we deduce the network of effective interactions between the polarity proteins. RomR lies at the root of this network, promoting polar localization of the other components, while polarity arises from interconnected negative and positive feedbacks mediated by the small GTPase MglA and its cognate GAP MglB, respectively. We rationalize this network topology as operating as a spatial toggle switch, providing stable polarity for persistent cell movement whilst remaining responsive to chemotactic signaling and thus capable of polarity inversions. Our results have implications not only for the understanding of polarity and motility in M. xanthus but also, more broadly, for dynamic cell polarity. The asymmetric localization of cellular components (polarity) is at the core of many important cellular functions including growth, division, differentiation and motility. However, important questions still remain regarding the design principles underlying polarity networks and how their activity can be controlled in space and time. We use the rod-shaped bacterium Myxococcus xanthus as a model to study polarity and its regulation. Like many bacteria, in M. xanthus a well-defined front-rear polarity axis enables efficient translocation. This polarity axis is defined by asymmetric polar localization of a switch-like GTPase and its cognate regulators, and can be reversed in response to signaling cues. Here we use a combination of quantitative experiments and data-driven theory to deduce the network of interactions among the M. xanthus polarity proteins and to show how the combination of positive- and negative-feedback interactions give rise to asymmetric polar protein localization. We rationalize this network topology as operating as a spatial toggle switch, providing stable polarity for persistent cell movement whilst remaining responsive to chemotactic signaling and capable of polarity inversions. Our results have broader implications for our understanding of dynamic cell polarity and GTPase regulation in both bacteria and eukaryotic cells.
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Affiliation(s)
| | - Filipe Tostevin
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Physik-Department, Technische Universität München, James Franck Straße, Garching, Germany
| | - Ulrich Gerland
- Physik-Department, Technische Universität München, James Franck Straße, Garching, Germany
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- * E-mail:
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37
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Establishing rod shape from spherical, peptidoglycan-deficient bacterial spores. Proc Natl Acad Sci U S A 2020; 117:14444-14452. [PMID: 32513721 DOI: 10.1073/pnas.2001384117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Chemical-induced spores of the Gram-negative bacterium Myxococcus xanthus are peptidoglycan (PG)-deficient. It is unclear how these spherical spores germinate into rod-shaped, walled cells without preexisting PG templates. We found that germinating spores first synthesize PG randomly on spherical surfaces. MglB, a GTPase-activating protein, forms a cluster that responds to the status of PG growth and stabilizes at one future cell pole. Following MglB, the Ras family GTPase MglA localizes to the second pole. MglA directs molecular motors to transport the bacterial actin homolog MreB and the Rod PG synthesis complexes away from poles. The Rod system establishes rod shape de novo by elongating PG at nonpolar regions. Thus, similar to eukaryotic cells, the interactions between GTPase, cytoskeletons, and molecular motors initiate spontaneous polarization in bacteria.
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38
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Scholivet A, Villion K, Wilhelm L, Latifi A. [The fascinating gliding motility of Myxococcus xanthus, essential to its social behaviours]. Med Sci (Paris) 2020; 36:416-419. [PMID: 32356722 DOI: 10.1051/medsci/2020067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anaïs Scholivet
- Master 2 Microbiologie Intégrative et Fondamentale, Aix Marseille Université, Marseille, France
| | - Katia Villion
- Master 2 Microbiologie Intégrative et Fondamentale, Aix Marseille Université, Marseille, France
| | - Linus Wilhelm
- Master 2 Microbiologie Intégrative et Fondamentale, Aix Marseille Université, Marseille, France
| | - Amel Latifi
- Aix Marseille Université, CNRS, LCB UMR 7283, IMM, Marseille, France
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Deng W, Fu T, Zhang Z, Jiang X, Xie J, Sun H, Hu P, Ren H, Zhou P, Liu Q, Long Q. L-lysine potentiates aminoglycosides against Acinetobacter baumannii via regulation of proton motive force and antibiotics uptake. Emerg Microbes Infect 2020; 9:639-650. [PMID: 32192413 PMCID: PMC7144275 DOI: 10.1080/22221751.2020.1740611] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acinetobacter baumannii, a Gram-negative opportunistic pathogen, is a leading cause of hospital- and community-acquired infections. Acinetobacter baumannii can rapidly acquire diverse resistance mechanisms and undergo genetic modifications that confer resistance and persistence to all currently used clinical antibiotics. In this study, we found exogenous L-lysine sensitizes Acinetobacter baumannii, other Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and a Gram-positive bacterium (Mycobacterium smegmatis) to aminoglycosides. Importantly, the combination of L-lysine with aminoglycosides killed clinically isolated multidrug-resistant Acinetobacter baumannii and persister cells. The exogenous L-lysine can increase proton motive force via transmembrane chemical gradient, resulting in aminoglycoside acumination that further accounts for reactive oxygen species production. The combination of L-lysine and antibiotics highlights a promising strategy against bacterial infection.
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Affiliation(s)
- Wanyan Deng
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Tiwei Fu
- Chongqing Key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Zhen Zhang
- Department of Clinical Laboratory, Chongqing General Hospital, Chongqing, People's Republic of China
| | - Xiao Jiang
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Jianping Xie
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Institute of Modern Biopharmaceuticals, Southwest University, Chongqing, People's Republic of China
| | - Hang Sun
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Peng Hu
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Hong Ren
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Peifu Zhou
- School of Ethnic-Minority Medicine, Guizhou Minzu University, Guizhou, People's Republic of China
| | - Qi Liu
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
| | - Quanxin Long
- Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR People's Republic of China
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40
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Qurbani K, Hamzah H. Intimate communication between Comamonas aquatica and Fusarium solani in remediation of heavy metal-polluted environments. Arch Microbiol 2020; 202:1397-1406. [DOI: 10.1007/s00203-020-01853-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/26/2020] [Accepted: 03/01/2020] [Indexed: 12/28/2022]
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Pérez-Burgos M, García-Romero I, Valvano MA, Søgaard Andersen L. Identification of the Wzx flippase, Wzy polymerase and sugar-modifying enzymes for spore coat polysaccharide biosynthesis in Myxococcus xanthus. Mol Microbiol 2020; 113:1189-1208. [PMID: 32064693 DOI: 10.1111/mmi.14486] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/11/2020] [Indexed: 12/28/2022]
Abstract
The rod-shaped cells of Myxococcus xanthus, a Gram-negative deltaproteobacterium, differentiate to environmentally resistant spores upon starvation or chemical stress. The environmental resistance depends on a spore coat polysaccharide that is synthesised by the ExoA-I proteins, some of which are part of a Wzx/Wzy-dependent pathway for polysaccharide synthesis and export; however, key components of this pathway have remained unidentified. Here, we identify and characterise two additional loci encoding proteins with homology to enzymes involved in polysaccharide synthesis and export, as well as sugar modification and show that six of the proteins encoded by these loci are essential for the formation of environmentally resistant spores. Our data support that MXAN_3260, renamed ExoM and MXAN_3026, renamed ExoJ, are the Wzx flippase and Wzy polymerase, respectively, responsible for translocation and polymerisation of the repeat unit of the spore coat polysaccharide. Moreover, we provide evidence that three glycosyltransferases (MXAN_3027/ExoK, MXAN_3262/ExoO and MXAN_3263/ExoP) and a polysaccharide deacetylase (MXAN_3259/ExoL) are important for formation of the intact spore coat, while ExoE is the polyisoprenyl-phosphate hexose-1-phosphate transferase responsible for initiating repeat unit synthesis, likely by transferring N-acetylgalactosamine-1-P to undecaprenyl-phosphate. Together, our data generate a more complete model of the Exo pathway for spore coat polysaccharide biosynthesis and export.
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Affiliation(s)
- María Pérez-Burgos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Lotte Søgaard Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Three-Dimensional Observations of an Aperiodic Oscillatory Gliding Behavior in Myxococcus xanthus Using Confocal Interference Reflection Microscopy. mSphere 2020; 5:5/1/e00846-19. [PMID: 31996414 PMCID: PMC6992375 DOI: 10.1128/msphere.00846-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
3D imaging of live bacteria with optical microscopy techniques is a challenge due to the small size of bacterial cells, meaning that previous studies have been limited to observing motility behavior in 2D. We introduce the application of confocal multiwavelength interference reflection microscopy to bacteria, which enables visualization of 3D motility behaviors in a single 2D image. Using the model organism Myxococcus xanthus, we identified novel motility behaviors that are not explained by current motility models, where gliding bacteria exhibit aperiodic changes in their adhesion to an underlying solid surface. We concluded that the 3D behavior was not linked to canonical motility mechanisms and that IRM could be applied to study a range of microbiological specimens with minimal adaptation to a commercial microscope. The deltaproteobacterium Myxococcus xanthus is a model for bacterial motility and has provided unprecedented insights into bacterial swarming behaviors. Fluorescence microscopy techniques have been invaluable in defining the mechanisms that are involved in gliding motility, but these have almost entirely been limited to two-dimensional (2D) studies, and there is currently no understanding of gliding motility in a three-dimensional (3D) context. We present here the first use of confocal interference reflection microscopy (IRM) to study gliding bacteria, revealing aperiodic oscillatory behavior with changes in the position of the basal membrane relative to the substrate on the order of 90 nm in vitro. First, we use a model planoconvex lens specimen to show how topological information can be obtained from the wavelength-dependent interference pattern in IRM. We then use IRM to observe gliding M. xanthus bacteria and show that cells undergo previously unobserved changes in their adhesion profile as they glide. We compare the wild type with mutants that have reduced motility, which also exhibit the same changes in the adhesion profile during gliding. We find that the general gliding behavior is independent of the proton motive force-generating complex AglRQS and suggest that the novel behavior that we present here may be a result of recoil and force transmission along the length of the cell body following firing of the type IV pili. IMPORTANCE 3D imaging of live bacteria with optical microscopy techniques is a challenge due to the small size of bacterial cells, meaning that previous studies have been limited to observing motility behavior in 2D. We introduce the application of confocal multiwavelength interference reflection microscopy to bacteria, which enables visualization of 3D motility behaviors in a single 2D image. Using the model organism Myxococcus xanthus, we identified novel motility behaviors that are not explained by current motility models, where gliding bacteria exhibit aperiodic changes in their adhesion to an underlying solid surface. We concluded that the 3D behavior was not linked to canonical motility mechanisms and that IRM could be applied to study a range of microbiological specimens with minimal adaptation to a commercial microscope.
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Abstract
The motility mechanism of certain prokaryotes has long been a mystery, since their motion, known as gliding, involves no external appendages. The physical principles behind gliding still remain poorly understood. Using myxobacteria as an example of such organisms, we identify here the physical principles behind gliding motility and develop a theoretical model that predicts a 2-regime behavior of the gliding speed as a function of the substrate stiffness. Our theory describes the elasto-capillary-hydrodynamic interactions between the membrane of the bacteria, the slime it secretes, and the soft substrate underneath. Defining gliding as the horizontal translation under zero net force, we find the 2-regime behavior is due to 2 distinct mechanisms of motility thrust. On mildly soft substrates, the thrust arises from bacterial shape deformations creating a flow of slime that exerts a pressure along the bacterial length. This pressure in conjunction with the bacterial shape provides the necessary thrust for propulsion. On very soft substrates, however, we show that capillary effects must be considered that lead to the formation of a ridge at the slime-substrate-air interface, thereby creating a thrust in the form of a localized pressure gradient at the bacterial leading edge. To test our theory, we perform experiments with isolated cells on agar substrates of varying stiffness and find the measured gliding speeds in good agreement with the predictions from our elasto-capillary-hydrodynamic model. The mechanisms reported here serve as an important step toward an accurate theory of friction and substrate-mediated interactions between bacteria proliferating in soft media.
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44
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Wang X, Kong Y, Zhao H, Yan X. Dependence of the
Bacillus subtilis
biofilm expansion rate on phenotypes and the morphology under different growing conditions. Dev Growth Differ 2019; 61:431-443. [DOI: 10.1111/dgd.12627] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/16/2019] [Accepted: 08/20/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Xiaoling Wang
- School of Mechanical Engineering University of Science and Technology Beijing Beijing China
- School of Engineering and Applied Sciences Harvard University Cambridge MA USA
| | - Yuhao Kong
- School of Mechanical Engineering University of Science and Technology Beijing Beijing China
| | - Hui Zhao
- State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing China
- University of Chinese Academy of Sciences Huairou China
| | - Xiaoqiang Yan
- School of Mechanical Engineering University of Science and Technology Beijing Beijing China
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45
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Pérez-Burgos M, García-Romero I, Jung J, Valvano MA, Søgaard-Andersen L. Identification of the lipopolysaccharide O-antigen biosynthesis priming enzyme and the O-antigen ligase in Myxococcus xanthus: critical role of LPS O-antigen in motility and development. Mol Microbiol 2019; 112:1178-1198. [PMID: 31332863 DOI: 10.1111/mmi.14354] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2019] [Indexed: 01/03/2023]
Abstract
Myxococcus xanthus is a model bacterium to study social behavior. At the cellular level, the different social behaviors of M. xanthus involve extensive cell-cell contacts. Here, we used bioinformatics, genetics, heterologous expression and biochemical experiments to identify and characterize the key enzymes in M. xanthus implicated in O-antigen and lipopolysaccharide (LPS) biosynthesis and examined the role of LPS O-antigen in M. xanthus social behaviors. We identified WbaPMx (MXAN_2922) as the polyisoprenyl-phosphate hexose-1-phosphate transferase responsible for priming O-antigen synthesis. In heterologous expression experiments, WbaPMx complemented a Salmonella enterica mutant lacking the endogenous WbaP that primes O-antigen synthesis, indicating that WbaPMx transfers galactose-1-P to undecaprenyl-phosphate. We also identified WaaLMx (MXAN_2919), as the O-antigen ligase that joins O-antigen to lipid A-core. Our data also support the previous suggestion that WzmMx (MXAN_4622) and WztMx (MXAN_4623) form the Wzm/Wzt ABC transporter. We show that mutations that block different steps in LPS O-antigen synthesis can cause pleiotropic phenotypes. Also, using a wbaPMx deletion mutant, we revisited the role of LPS O-antigen and demonstrate that it is important for gliding motility, conditionally important for type IV pili-dependent motility and required to complete the developmental program leading to the formation of spore-filled fruiting bodies.
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Affiliation(s)
- María Pérez-Burgos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Inmaculada García-Romero
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7BL, UK
| | - Jana Jung
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7BL, UK
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
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46
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Jacek P, Ryngajłło M, Bielecki S. Structural changes of bacterial nanocellulose pellicles induced by genetic modification of Komagataeibacter hansenii ATCC 23769. Appl Microbiol Biotechnol 2019; 103:5339-5353. [PMID: 31037382 PMCID: PMC6570709 DOI: 10.1007/s00253-019-09846-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 01/08/2023]
Abstract
Bacterial nanocellulose (BNC) synthesized by Komagataeibacter hansenii is a polymer that recently gained an attention of tissue engineers, since its features make it a suitable material for scaffolds production. Nevertheless, it is still necessary to modify BNC to improve its properties in order to make it more suitable for biomedical use. One approach to address this issue is to genetically engineer K. hansenii cells towards synthesis of BNC with modified features. One of possible ways to achieve that is to influence the bacterial movement or cell morphology. In this paper, we described for the first time, K. hansenii ATCC 23769 motA+ and motB+ overexpression mutants, which displayed elongated cell phenotype, increased motility, and productivity. Moreover, the mutant cells produced thicker ribbons of cellulose arranged in looser network when compared to the wild-type strain. In this paper, we present a novel development in obtaining BNC membranes with improved properties using genetic engineering tools.
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Affiliation(s)
- Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
| | - Małgorzata Ryngajłło
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
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47
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Liu G, Patch A, Bahar F, Yllanes D, Welch RD, Marchetti MC, Thutupalli S, Shaevitz JW. Self-Driven Phase Transitions Drive Myxococcus xanthus Fruiting Body Formation. PHYSICAL REVIEW LETTERS 2019; 122:248102. [PMID: 31322369 DOI: 10.1103/physrevlett.122.248102] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Indexed: 06/10/2023]
Abstract
Combining high-resolution single cell tracking experiments with numerical simulations, we show that starvation-induced fruiting body formation in Myxococcus xanthus is a phase separation driven by cells that tune their motility over time. The phase separation can be understood in terms of cell density and a dimensionless Péclet number that captures cell motility through speed and reversal frequency. Our work suggests that M. xanthus takes advantage of a self-driven nonequilibrium phase transition that can be controlled at the single cell level.
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Affiliation(s)
- Guannan Liu
- Joseph Henry Laboratories of Physics and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Adam Patch
- Department of Physics and Soft and Living Matter Program, Syracuse University, Syracuse, New York 13244, USA
| | - Fatmagül Bahar
- Department of Biology, Syracuse University, Syracuse, New York 13244, USA
| | - David Yllanes
- Department of Physics and Soft and Living Matter Program, Syracuse University, Syracuse, New York 13244, USA
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), 50009 Zaragoza, Spain
| | - Roy D Welch
- Department of Biology, Syracuse University, Syracuse, New York 13244, USA
| | - M Cristina Marchetti
- Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Shashi Thutupalli
- Simons Center for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute for Fundamental Research, Bangalore 560065, India
| | - Joshua W Shaevitz
- Joseph Henry Laboratories of Physics and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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48
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Abstract
Some bacteria glide mysteriously on surfaces without using flagella, pili, or other external appendages. Recent studies suggest how gliding motors in the inner membrane may transduce force to the cell surface.
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Affiliation(s)
- Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.
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49
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Spatial control of the GTPase MglA by localized RomR–RomX GEF and MglB GAP activities enables Myxococcus xanthus motility. Nat Microbiol 2019; 4:1344-1355. [DOI: 10.1038/s41564-019-0451-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 04/08/2019] [Indexed: 11/08/2022]
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50
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Gómez-Santos N, Glatter T, Koebnik R, Świątek-Połatyńska MA, Søgaard-Andersen L. A TonB-dependent transporter is required for secretion of protease PopC across the bacterial outer membrane. Nat Commun 2019; 10:1360. [PMID: 30911012 PMCID: PMC6434023 DOI: 10.1038/s41467-019-09366-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 03/05/2019] [Indexed: 01/02/2023] Open
Abstract
TonB-dependent transporters (TBDTs) are ubiquitous outer membrane β-barrel proteins that import nutrients and bacteriocins across the outer membrane in a proton motive force-dependent manner, by directly connecting to the ExbB/ExbD/TonB system in the inner membrane. Here, we show that the TBDT Oar in Myxococcus xanthus is required for secretion of a protein, protease PopC, to the extracellular milieu. PopC accumulates in the periplasm before secretion across the outer membrane, and the proton motive force has a role in secretion to the extracellular milieu. Reconstitution experiments in Escherichia coli demonstrate that secretion of PopC across the outer membrane not only depends on Oar but also on the ExbB/ExbD/TonB system. Our results indicate that TBDTs and the ExbB/ExbD/TonB system may have roles not only in import processes but also in secretion of proteins. TonB-dependent transporters (TBDTs) are outer membrane proteins that import nutrients and bacteriocins in bacteria. Here, Gómez-Santos et al. show that a TBDT is required for secretion of a protease in Myxococcus xanthus, suggesting that some TBDTs may be involved in protein secretion.
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Affiliation(s)
- Nuria Gómez-Santos
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Timo Glatter
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany
| | - Ralf Koebnik
- IRD, Cirad, Interactions Plantes Microorganismes Environnement, University of Montpellier, 34394, Montpellier, France
| | | | - Lotte Søgaard-Andersen
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043, Marburg, Germany.
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