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Rombouts S, Mas A, Le Gall A, Fiche JB, Mignot T, Nollmann M. Multi-scale dynamic imaging reveals that cooperative motility behaviors promote efficient predation in bacteria. Nat Commun 2023; 14:5588. [PMID: 37696789 PMCID: PMC10495355 DOI: 10.1038/s41467-023-41193-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 08/21/2023] [Indexed: 09/13/2023] Open
Abstract
Many species, such as fish schools or bird flocks, rely on collective motion to forage, prey, or escape predators. Likewise, Myxococcus xanthus forages and moves collectively to prey and feed on other bacterial species. These activities require two distinct motility machines enabling adventurous (A) and social (S) gliding, however when and how these mechanisms are used has remained elusive. Here, we address this long-standing question by applying multiscale semantic cell tracking during predation. We show that: (1) foragers and swarms can comprise A- and S-motile cells, with single cells exchanging frequently between these groups; (2) A-motility is critical to ensure the directional movement of both foragers and swarms; (3) the combined action of A- and S-motile cells within swarms leads to increased predation efficiencies. These results challenge the notion that A- and S-motilities are exclusive to foragers and swarms, and show that these machines act synergistically to enhance predation efficiency.
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Affiliation(s)
- Sara Rombouts
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090, Montpellier, France
| | - Anna Mas
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090, Montpellier, France
| | - Antoine Le Gall
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090, Montpellier, France.
| | - Jean-Bernard Fiche
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090, Montpellier, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Marseille, France
| | - Marcelo Nollmann
- Centre de Biologie Structurale, CNRS UMR 5048, INSERM U1054, Université de Montpellier, 60 rue de Navacelles, 34090, Montpellier, France.
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2
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Black ME, Shaevitz JW. Rheological Dynamics of Active Myxococcus xanthus Populations during Development. PHYSICAL REVIEW LETTERS 2023; 130:218402. [PMID: 37295076 DOI: 10.1103/physrevlett.130.218402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/21/2023] [Indexed: 06/12/2023]
Abstract
The bacterium Myxococcus xanthus produces multicellular droplets called fruiting bodies when starved. These structures form initially through the active dewetting of a vegetative biofilm into surface-associated droplets. This motility-driven aggregation is succeeded by a primitive developmental process in which cells in the droplets mature into nonmotile spores. Here, we use atomic force microscopy to probe the mechanics of these droplets throughout their formation. Using a combination of time- and frequency-domain rheological experiments, we characterize and develop a simple model of the linear viscoelasticity of these aggregates. We then use this model to quantify how cellular behaviors predominant at different developmental times-motility during the dewetting phase and cellular sporulation during later development-manifest as decreased droplet viscosity and increased elasticity, respectively.
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Affiliation(s)
- Matthew E Black
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Joshua W Shaevitz
- Joseph Henry Laboratories of Physics and the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
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3
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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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4
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Letarov AV, Letarova MA. The Burden of Survivors: How Can Phage Infection Impact Non-Infected Bacteria? Int J Mol Sci 2023; 24:2733. [PMID: 36769055 PMCID: PMC9917116 DOI: 10.3390/ijms24032733] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/16/2023] [Accepted: 01/26/2023] [Indexed: 02/04/2023] Open
Abstract
The contemporary understanding of complex interactions in natural microbial communities and the numerous mechanisms of bacterial communication challenge the classical concept of bacteria as unicellular organisms. Microbial populations, especially those in densely populated habitats, appear to behave cooperatively, coordinating their reactions in response to different stimuli and behaving as a quasi-tissue. The reaction of such systems to viral infection is likely to go beyond each cell or species tackling the phage attack independently. Bacteriophage infection of a fraction of the microbial community may also exert an influence on the physiological state and/or phenotypic features of those cells that have not yet had direct contact with the virus or are even intrinsically unable to become infected by the particular virus. These effects may be mediated by sensing the chemical signals released by lysing or by infected cells as well as by more indirect mechanisms.
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Affiliation(s)
- Andrey V. Letarov
- Winogradsky Institute of Microbiology, RC Biotechnology RAS, 119991 Moscow, Russia
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5
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Bautista S, Schmidt V, Guiseppi A, Mauriello EMF, Attia B, Elantak L, Mignot T, Mercier R. FrzS acts as a polar beacon to recruit SgmX, a central activator of type IV pili during Myxococcus xanthus motility. EMBO J 2022; 42:e111661. [PMID: 36345779 PMCID: PMC9811614 DOI: 10.15252/embj.2022111661] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
In rod-shaped bacteria, type IV pili (Tfp) promote twitching motility by assembling and retracting at the cell pole. In Myxococcus xanthus, a bacterium that moves in highly coordinated cell groups, Tfp are activated by a polar activator protein, SgmX. However, while it is known that the Ras-like protein MglA is required for unipolar targeting, how SgmX accesses the cell pole to activate Tfp is unknown. Here, we demonstrate that a polar beacon protein, FrzS, recruits SgmX at the cell pole. We identified two main functional domains, including a Tfp-activating domain and a polar-binding domain. Within the latter, we show that the direct binding of MglA-GTP unveils a hidden motif that binds directly to the FrzS N-terminal response regulator (CheY). Structural analyses reveal that this binding occurs through a novel binding interface for response regulator domains. In conclusion, the findings unveil the protein interaction network leading to the spatial activation of Tfp at the cell pole. This tripartite system is at the root of complex collective behaviours in this predatory bacterium.
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Affiliation(s)
- Sarah Bautista
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7283)MarseilleFrance
| | - Victoria Schmidt
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7255)MarseilleFrance
| | - Annick Guiseppi
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7283)MarseilleFrance
| | - Emillia M F Mauriello
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7283)MarseilleFrance
| | - Bouchra Attia
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7255)MarseilleFrance
| | - Latifa Elantak
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7255)MarseilleFrance
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7283)MarseilleFrance
| | - Romain Mercier
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la MéditerranéeAix‐Marseille Université‐CNRS (UMR7283)MarseilleFrance
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6
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La Fortezza M, Rendueles O, Keller H, Velicer GJ. Hidden paths to endless forms most wonderful: ecology latently shapes evolution of multicellular development in predatory bacteria. Commun Biol 2022; 5:977. [PMID: 36114258 PMCID: PMC9481553 DOI: 10.1038/s42003-022-03912-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/30/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractEcological causes of developmental evolution, for example from predation, remain much investigated, but the potential importance of latent phenotypes in eco-evo-devo has received little attention. Using the predatory bacterium Myxococcus xanthus, which undergoes aggregative fruiting body development upon starvation, we tested whether adaptation to distinct growth environments that do not induce development latently alters developmental phenotypes under starvation conditions that do induce development. In an evolution experiment named MyxoEE-3, growing M. xanthus populations swarmed across agar surfaces while adapting to conditions varying at factors such as surface stiffness or prey identity. Such ecological variation during growth was found to greatly impact the latent evolution of development, including fruiting body morphology, the degree of morphological trait correlation, reaction norms, degrees of developmental plasticity and stochastic diversification. For example, some prey environments promoted retention of developmental proficiency whereas others led to its systematic loss. Our results have implications for understanding evolutionary interactions among predation, development and motility in myxobacterial life cycles, and, more broadly, how ecology can profoundly shape the evolution of developmental systems latently rather than by direct selection on developmental features.
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7
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Thiery S, Turowski P, Berleman JE, Kaimer C. The predatory soil bacterium Myxococcus xanthus combines a Tad- and an atypical type 3-like protein secretion system to kill bacterial cells. Cell Rep 2022; 40:111340. [PMID: 36103818 DOI: 10.1016/j.celrep.2022.111340] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/20/2022] [Accepted: 08/18/2022] [Indexed: 11/03/2022] Open
Abstract
Predatory Myxobacteria employ a multilayered predation strategy to kill and lyse soil microorganisms. Aiming to dissect the mechanism of contact-dependent killing of bacteria, we analyze four protein secretion systems in Myxococcus xanthus and investigate the predation of mutant strains on different timescales. We find that a Tad-like and a type 3-like secretion system (Tad and T3SS∗) fulfill distinct functions during contact-dependent prey killing: the Tad-like system is necessary to induce prey cell death, while the needle-less T3SS∗ initiates prey lysis. Fluorescence microscopy reveals that components of both systems interdependently localize to the predator-prey contact site prior to killing. Swarm expansion assays show that both Tad and T3SS∗ are required to handle live prey and that nutrient extraction from prey bacteria is sufficient to power M. xanthus motility. In conclusion, our observations indicate the functional interplay of two types of secretion systems for killing and lysis of bacterial cells.
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Affiliation(s)
- Susanne Thiery
- Department of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - Pia Turowski
- Department of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany
| | - James E Berleman
- Department of Biology, St. Mary's College, Moraga, CA 94556, USA
| | - Christine Kaimer
- Department of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, 44801 Bochum, Germany.
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8
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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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9
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Dye KJ, Yang Z. Analysis of Myxococcus xanthus Vegetative Biofilms With Microtiter Plates. Front Microbiol 2022; 13:894562. [PMID: 35572678 PMCID: PMC9100584 DOI: 10.3389/fmicb.2022.894562] [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: 03/11/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
The bacterium Myxococcus xanthus forms both developmental and vegetative types of biofilms. While the former has been studied on both agar plates and submerged surfaces, the latter has been investigated predominantly on agar surfaces as swarming colonies. Here we describe the development of a microplate-based assay for the submerged biofilms of M. xanthus under vegetative conditions. We examined the impacts of inoculation, aeration, and temperature to optimize the conditions for the assay. Aeration was observed to be critical for the effective development of submerged biofilms by M. xanthus, an obligate aerobic bacterium. In addition, temperature plays an important role in the development of M. xanthus submerged biofilms. It is well established that the formation of submerged biofilms by many bacteria requires both exopolysaccharide (EPS) and the type IV pilus (T4P). EPS constitutes part of the biofilm matrix that maintains and organizes bacterial biofilms while the T4P facilitates surface attachment as adhesins. For validation, we used our biofilm assay to examine a multitude of M. xanthus strains with various EPS and T4P phenotypes. The results indicate that the levels of EPS, but not of piliation, positively correlate with submerged biofilm formation in M. xanthus.
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10
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Saïdi F, Jolivet NY, Lemon DJ, Nakamura A, Belgrave AM, Garza AG, Veyrier FJ, Islam ST. Bacterial glycocalyx integrity drives multicellular swarm biofilm dynamism. Mol Microbiol 2021; 116:1151-1172. [PMID: 34455651 DOI: 10.1111/mmi.14803] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/24/2022]
Abstract
Exopolysaccharide (EPS) layers on the bacterial cell surface are key determinants of biofilm establishment and maintenance, leading to the formation of higher-order 3D structures that confer numerous survival benefits to a cell community. In addition to a specific cell-associated EPS glycocalyx, we recently revealed that the social δ-proteobacterium Myxococcus xanthus secretes a novel biosurfactant polysaccharide (BPS) to the extracellular milieu. Together, secretion of the two polymers (EPS and BPS) is required for type IV pilus (T4P)-dependent swarm expansion via spatio-specific biofilm expression profiles. Thus the synergy between EPS and BPS secretion somehow modulates the multicellular lifecycle of M. xanthus. Herein, we demonstrate that BPS secretion functionally alters the EPS glycocalyx via destabilization of the latter, fundamentally changing the characteristics of the cell surface. This impacts motility behaviors at the single-cell level and the aggregative capacity of cells in groups via cell-surface EPS fibril formation as well as T4P production, stability, and positioning. These changes modulate the structure of swarm biofilms via cell layering, likely contributing to the formation of internal swarm polysaccharide architecture. Together, these data reveal the manner by which the combined secretion of two distinct polymers induces single-cell changes that modulate swarm biofilm communities.
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Affiliation(s)
- Fares Saïdi
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, Quebec, Canada.,PROTEO, The Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Québec, Quebec, Canada
| | - Nicolas Y Jolivet
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, Quebec, Canada.,PROTEO, The Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Québec, Quebec, Canada
| | - David J Lemon
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Arnaldo Nakamura
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, Quebec, Canada
| | - Akeisha M Belgrave
- Integrated Sciences Program, Harrisburg University of Science & Technology, Harrisburg, Pennsylvania, USA
| | - Anthony G Garza
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Frédéric J Veyrier
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, Quebec, Canada
| | - Salim T Islam
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, Université du Québec, Institut Pasteur International Network, Laval, Quebec, Canada.,PROTEO, The Quebec Network for Research on Protein Function, Engineering, and Applications, Université Laval, Québec, Quebec, Canada
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11
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Pérez-Burgos M, Søgaard-Andersen L. Biosynthesis and function of cell-surface polysaccharides in the social bacterium Myxococcus xanthus. Biol Chem 2021; 401:1375-1387. [PMID: 32769218 DOI: 10.1515/hsz-2020-0217] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/04/2020] [Indexed: 12/29/2022]
Abstract
In bacteria, cell-surface polysaccharides fulfill important physiological functions, including interactions with the environment and other cells as well as protection from diverse stresses. The Gram-negative delta-proteobacterium Myxococcus xanthus is a model to study social behaviors in bacteria. M. xanthus synthesizes four cell-surface polysaccharides, i.e., exopolysaccharide (EPS), biosurfactant polysaccharide (BPS), spore coat polysaccharide, and O-antigen. Here, we describe recent progress in elucidating the three Wzx/Wzy-dependent pathways for EPS, BPS and spore coat polysaccharide biosynthesis and the ABC transporter-dependent pathway for O-antigen biosynthesis. Moreover, we describe the functions of these four cell-surface polysaccharides in the social life cycle of M. xanthus.
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Affiliation(s)
- María Pérez-Burgos
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, D-35043 Marburg, Germany
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, D-35043 Marburg, Germany
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12
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Ahearne A, Albataineh H, Dowd SE, Stevens DC. Assessment of Evolutionary Relationships for Prioritization of Myxobacteria for Natural Product Discovery. Microorganisms 2021; 9:microorganisms9071376. [PMID: 34202719 PMCID: PMC8307915 DOI: 10.3390/microorganisms9071376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/03/2021] [Accepted: 06/21/2021] [Indexed: 02/06/2023] Open
Abstract
Discoveries of novel myxobacteria have started to unveil the potentially vast phylogenetic diversity within the family Myxococcaceae and have brought about an updated approach to myxobacterial classification. While traditional approaches focused on morphology, 16S gene sequences, and biochemistry, modern methods including comparative genomics have provided a more thorough assessment of myxobacterial taxonomy. Herein, we utilize long-read genome sequencing for two myxobacteria previously classified as Archangium primigenium and Chondrococcus macrosporus, as well as four environmental myxobacteria newly isolated for this study. Average nucleotide identity and digital DNA-DNA hybridization scores from comparative genomics suggest previously classified as A. primigenium to instead be a novel member of the genus Melittangium, C. macrosporus to be a potentially novel member of the genus Corallococcus with high similarity to Corallococcus exercitus, and the four isolated myxobacteria to include another novel Corallococcus species, a novel Pyxidicoccus species, a strain of Corallococcus exiguus, and a potentially novel Myxococcus species with high similarity to Myxococcus stipitatus. We assess the biosynthetic potential of each sequenced myxobacterium and suggest that genus-level conservation of biosynthetic pathways support our preliminary taxonomic assignment. Altogether, we suggest that long-read genome sequencing benefits the classification of myxobacteria and improves determination of biosynthetic potential for prioritization of natural product discovery.
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Affiliation(s)
- Andrew Ahearne
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA; (A.A.); (H.A.)
| | - Hanan Albataineh
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA; (A.A.); (H.A.)
| | - Scot E. Dowd
- MR DNA, Molecular Research LP, Shallowater, TX 79363, USA;
| | - D. Cole Stevens
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS 38677, USA; (A.A.); (H.A.)
- Correspondence: ; Tel.: +1-662-915-5730
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13
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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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14
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Myxococcus xanthus predation of Gram-positive or Gram-negative bacteria is mediated by different bacteriolytic mechanisms. Appl Environ Microbiol 2021; 87:AEM.02382-20. [PMID: 33310723 PMCID: PMC8090889 DOI: 10.1128/aem.02382-20] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myxococcus xanthus kills other species to use their biomass as energy source. Its predation mechanisms allow feeding on a broad spectrum of bacteria, but the identity of predation effectors and their mode of action remains largely unknown. We initially focused on the role of hydrolytic enzymes for prey killing and compared the activity of secreted M. xanthus proteins against four prey strains. 72 secreted proteins were identified by mass spectrometry, and among them a family 19 glycoside hydrolase that displayed bacteriolytic activity in vivo and in vitro This enzyme, which we name LlpM (lectin/lysozyme-like protein of M. xanthus), was not essential for predation, indicating that additional secreted components are required to disintegrate prey. Furthermore, secreted proteins lysed only Gram-positive, but not Gram-negative species. We thus compared the killing of different preys by cell-associated mechanisms: Individual M. xanthus cells killed all four test strains in a cell-contact dependent manner, but were only able to disintegrate Gram-negative, not Gram-positive cell envelopes. Thus, our data indicate that M. xanthus uses different, multifactorial mechanisms for killing and degrading different preys. Besides secreted enzymes, cell-associated mechanisms that have not been characterized so far, appear to play a major role for prey killing.IMPORTANCEPredation is an important survival strategy of the widespread myxobacteria, but it remains poorly understood on the mechanistic level. Without a basic understanding of how prey cell killing and consumption is achieved, it also remains difficult to investigate the role of predation for the complex myxobacterial lifestyle, reciprocal predator-prey relationships or the impact of predation on complex bacterial soil communities.We study predation in the established model organism Myxococcus xanthus, aiming to dissect the molecular mechanisms of prey cell lysis. In this study, we addressed the role of secreted bacteriolytic proteins, as well as potential mechanistic differences in the predation of Gram-positive and Gram-negative bacteria. Our observation shows that secreted enzymes are sufficient for killing and degrading Gram-positive species, but that cell-associated mechanisms may play a major role for killing Gram-negative and Gram-positive prey on fast timescales.
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Dinet C, Michelot A, Herrou J, Mignot T. Linking single-cell decisions to collective behaviours in social bacteria. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190755. [PMID: 33487114 DOI: 10.1098/rstb.2019.0755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Social bacteria display complex behaviours whereby thousands of cells collectively and dramatically change their form and function in response to nutrient availability and changing environmental conditions. In this review, we focus on Myxococcus xanthus motility, which supports spectacular transitions based on prey availability across its life cycle. A large body of work suggests that these behaviours require sensory capacity implemented at the single-cell level. Focusing on recent genetic work on a core cellular pathway required for single-cell directional decisions, we argue that signal integration, multi-modal sensing and memory are at the root of decision making leading to multicellular behaviours. Hence, Myxococcus may be a powerful biological system to elucidate how cellular building blocks cooperate to form sensory multicellular assemblages, a possible origin of cognitive mechanisms in biological systems. This article is part of the theme issue 'Basal cognition: conceptual tools and the view from the single cell'.
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Affiliation(s)
- Céline Dinet
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, 31 Chemin Joseph Aiguier, 13009 Marseille, France.,Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Alphée Michelot
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Julien Herrou
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix-Marseille University, 31 Chemin Joseph Aiguier, 13009 Marseille, France
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16
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The polar Ras-like GTPase MglA activates type IV pilus via SgmX to enable twitching motility in Myxococcus xanthus. Proc Natl Acad Sci U S A 2020; 117:28366-28373. [PMID: 33093210 PMCID: PMC7668184 DOI: 10.1073/pnas.2002783117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The type IV pilus (Tfp) is a multipurpose machine found on bacterial surfaces that works by cycles of synthesis/retraction of a pilin fiber. During surface (twitching) motility, the coordinated actions of multiple Tfps at the cell pole promotes single cells and synchronized group movements. Here, directly observing polar Tfp machines in action during motility of Myxococcus xanthus, we identified the mechanism underlying pole-specific Tfps activation. In this process, the Ras-like protein MglA targets a novel essential Tfp-activator, SgmX, to the pole, ensuring both the unipolar activation of Tfps and its switching to the opposite pole when cells reverse their movement. Thus, a dynamic cascade of polar activators regulates multicellular movements, a feature that is likely conserved in other twitching bacteria. Type IV pili (Tfp) are highly conserved macromolecular structures that fulfill diverse cellular functions, such as adhesion to host cells, the import of extracellular DNA, kin recognition, and cell motility (twitching). Outstandingly, twitching motility enables a poorly understood process by which highly coordinated groups of hundreds of cells move in cooperative manner, providing a basis for multicellular behaviors, such as biofilm formation. In the social bacteria Myxococcus xanthus, we know that twitching motility is under the dependence of the small GTPase MglA, but the underlying molecular mechanisms remain elusive. Here we show that MglA complexed to GTP recruits a newly characterized Tfp regulator, termed SgmX, to activate Tfp machines at the bacterial cell pole. This mechanism also ensures spatial regulation of Tfp, explaining how MglA switching provokes directional reversals. This discovery paves the way to elucidate how polar Tfp machines are regulated to coordinate multicellular movements, a conserved feature in twitching bacteria.
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17
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Miyata M, Robinson RC, Uyeda TQP, Fukumori Y, Fukushima SI, Haruta S, Homma M, Inaba K, Ito M, Kaito C, Kato K, Kenri T, Kinosita Y, Kojima S, Minamino T, Mori H, Nakamura S, Nakane D, Nakayama K, Nishiyama M, Shibata S, Shimabukuro K, Tamakoshi M, Taoka A, Tashiro Y, Tulum I, Wada H, Wakabayashi KI. Tree of motility - A proposed history of motility systems in the tree of life. Genes Cells 2020; 25:6-21. [PMID: 31957229 PMCID: PMC7004002 DOI: 10.1111/gtc.12737] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/11/2019] [Accepted: 11/17/2019] [Indexed: 12/27/2022]
Abstract
Motility often plays a decisive role in the survival of species. Five systems of motility have been studied in depth: those propelled by bacterial flagella, eukaryotic actin polymerization and the eukaryotic motor proteins myosin, kinesin and dynein. However, many organisms exhibit surprisingly diverse motilities, and advances in genomics, molecular biology and imaging have showed that those motilities have inherently independent mechanisms. This makes defining the breadth of motility nontrivial, because novel motilities may be driven by unknown mechanisms. Here, we classify the known motilities based on the unique classes of movement‐producing protein architectures. Based on this criterion, the current total of independent motility systems stands at 18 types. In this perspective, we discuss these modes of motility relative to the latest phylogenetic Tree of Life and propose a history of motility. During the ~4 billion years since the emergence of life, motility arose in Bacteria with flagella and pili, and in Archaea with archaella. Newer modes of motility became possible in Eukarya with changes to the cell envelope. Presence or absence of a peptidoglycan layer, the acquisition of robust membrane dynamics, the enlargement of cells and environmental opportunities likely provided the context for the (co)evolution of novel types of motility.
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Affiliation(s)
- Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan.,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan
| | - Robert C Robinson
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan.,School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Taro Q P Uyeda
- Department of Physics, Faculty of Science and Technology, Waseda University, Tokyo, Japan
| | - Yoshihiro Fukumori
- Faculty of Natural System, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan.,WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - Shun-Ichi Fukushima
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Shin Haruta
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Masahiro Ito
- Graduate School of Life Sciences, Toyo University, Gunma, Japan
| | - Chikara Kaito
- Laboratory of Microbiology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Kentaro Kato
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Miyagi, Japan
| | - Tsuyoshi Kenri
- Laboratory of Mycoplasmas and Haemophilus, Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Hiroyuki Mori
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shuichi Nakamura
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Miyagi, Japan
| | - Daisuke Nakane
- Department of Physics, Gakushuin University, Tokyo, Japan
| | - Koji Nakayama
- Department of Microbiology and Oral Infection, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Masayoshi Nishiyama
- Department of Physics, Faculty of Science and Engineering, Kindai University, Osaka, Japan
| | - Satoshi Shibata
- Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Katsuya Shimabukuro
- Department of Chemical and Biological Engineering, National Institute of Technology, Ube College, Yamaguchi, Japan
| | - Masatada Tamakoshi
- Department of Molecular Biology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Azuma Taoka
- Faculty of Natural System, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan.,WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan
| | - Yosuke Tashiro
- Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Isil Tulum
- Department of Botany, Faculty of Science, Istanbul University, Istanbul, Turkey
| | - Hirofumi Wada
- Department of Physics, Graduate School of Science and Engineering, Ritsumeikan University, Shiga, Japan
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
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18
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Thiery S, Kaimer C. The Predation Strategy of Myxococcus xanthus. Front Microbiol 2020; 11:2. [PMID: 32010119 PMCID: PMC6971385 DOI: 10.3389/fmicb.2020.00002] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/03/2020] [Indexed: 11/20/2022] Open
Abstract
Myxobacteria are ubiquitous in soil environments. They display a complex life cycle: vegetatively growing cells coordinate their motility to form multicellular swarms, which upon starvation aggregate into large fruiting bodies where cells differentiate into spores. In addition to growing as saprophytes, Myxobacteria are predators that actively kill bacteria of other species to consume their biomass. In this review, we summarize research on the predation behavior of the model myxobacterium Myxococcus xanthus, which can access nutrients from a broad spectrum of microorganisms. M. xanthus displays an epibiotic predation strategy, i.e., it induces prey lysis from the outside and feeds on the released biomass. This predatory behavior encompasses various processes: Gliding motility and induced cell reversals allow M. xanthus to encounter prey and to remain within the area to sweep up its biomass, which causes the characteristic “rippling” of preying populations. Antibiotics and secreted bacteriolytic enzymes appear to be important predation factors, which are possibly targeted to prey cells with the aid of outer membrane vesicles. However, certain bacteria protect themselves from M. xanthus predation by forming mechanical barriers, such as biofilms and mucoid colonies, or by secreting antibiotics. Further understanding the molecular mechanisms that mediate myxobacterial predation will offer fascinating insight into the reciprocal relationships of bacteria in complex communities, and might spur application-oriented research on the development of novel antibacterial strategies.
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Affiliation(s)
- Susanne Thiery
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Christine Kaimer
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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19
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MglA functions as a three-state GTPase to control movement reversals of Myxococcus xanthus. Nat Commun 2019; 10:5300. [PMID: 31757955 PMCID: PMC6876712 DOI: 10.1038/s41467-019-13274-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/24/2019] [Indexed: 01/30/2023] Open
Abstract
In Myxococcus xanthus, directed movement is controlled by pole-to-pole oscillations of the small GTPase MglA and its GAP MglB. Direction reversals require that MglA is inactivated by MglB, yet paradoxically MglA and MglB are located at opposite poles at reversal initiation. Here we report the complete MglA/MglB structural cycle combined to GAP kinetics and in vivo motility assays, which uncovers that MglA is a three-state GTPase and suggests a molecular mechanism for concerted MglA/MglB relocalizations. We show that MglA has an atypical GTP-bound state (MglA-GTP*) that is refractory to MglB and is re-sensitized by a feedback mechanism operated by MglA-GDP. By identifying and mutating the pole-binding region of MglB, we then provide evidence that the MglA-GTP* state exists in vivo. These data support a model in which MglA-GDP acts as a soluble messenger to convert polar MglA-GTP* into a diffusible MglA-GTP species that re-localizes to the opposite pole during reversals. In Myxococcus xanthus, directed movement is controlled by pole-to-pole oscillations of the small GTPase MglA and its GAP MglB. Here authors report the complete MglA/MglB structural cycle and uncover that MglA is a three-state GTPase that adopts an atypical GTP-bound state that is refractory to inactivation by MglB.
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20
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Herrou J, Mignot T. Dynamic polarity control by a tunable protein oscillator in bacteria. Curr Opin Cell Biol 2019; 62:54-60. [PMID: 31627169 DOI: 10.1016/j.ceb.2019.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/09/2019] [Accepted: 09/05/2019] [Indexed: 01/30/2023]
Abstract
In bacteria, cell polarization involves the controlled targeting of specific proteins to the poles, defining polar identity and function. How a specific protein is targeted to one pole and what are the processes that facilitate its dynamic relocalization to the opposite pole is still unclear. The Myxococcus xanthus polarization example illustrates how the dynamic and asymmetric localization of polar proteins enable a controlled and fast switch of polarity. In M. xanthus, the opposing polar distribution of the small GTPase MglA and its cognate activating protein MglB defines the direction of movement of the cell. During a reversal event, the switch of direction is triggered by the Frz chemosensory system, which controls polarity reversals through a so-called gated relaxation oscillator. In this review, we discuss how this genetic architecture can provoke sharp behavioral transitions depending on Frz activation levels, which is central to multicellular behaviors in this bacterium.
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Affiliation(s)
- Julien Herrou
- Laboratoire de Chimie Bactérienne, CNRS - Aix Marseille University UMR 7283, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, CNRS - Aix Marseille University UMR 7283, Institut de Microbiologie de la Méditerranée, Marseille, France.
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21
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Muñoz-Dorado J, Moraleda-Muñoz A, Marcos-Torres FJ, Contreras-Moreno FJ, Martin-Cuadrado AB, Schrader JM, Higgs PI, Pérez J. Transcriptome dynamics of the Myxococcus xanthus multicellular developmental program. eLife 2019; 8:e50374. [PMID: 31609203 PMCID: PMC6791715 DOI: 10.7554/elife.50374] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/04/2019] [Indexed: 01/09/2023] Open
Abstract
The bacterium Myxococcus xanthus exhibits a complex multicellular life cycle. In the presence of nutrients, cells prey cooperatively. Upon starvation, they enter a developmental cycle wherein cells aggregate to produce macroscopic fruiting bodies filled with resistant myxospores. We used RNA-Seq technology to examine the transcriptome of the 96 hr developmental program. These data revealed that 1415 genes were sequentially expressed in 10 discrete modules, with expression peaking during aggregation, in the transition from aggregation to sporulation, or during sporulation. Analysis of genes expressed at each specific time point provided insights as to how starving cells obtain energy and precursors necessary for assembly of fruiting bodies and into developmental production of secondary metabolites. This study offers the first global view of developmental transcriptional profiles and provides important tools and resources for future studies.
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Affiliation(s)
- José Muñoz-Dorado
- Departamento de Microbiología, Facultad de CienciasUniversidad de GranadaGranadaSpain
| | | | | | | | | | - Jared M Schrader
- Department of Biological SciencesWayne State UniversityDetroitUnited States
| | - Penelope I Higgs
- Department of Biological SciencesWayne State UniversityDetroitUnited States
| | - Juana Pérez
- Departamento de Microbiología, Facultad de CienciasUniversidad de GranadaGranadaSpain
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22
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Ding SS, Schumacher LJ, Javer AE, Endres RG, Brown AEX. Shared behavioral mechanisms underlie C. elegans aggregation and swarming. eLife 2019; 8:e43318. [PMID: 31021320 PMCID: PMC6522220 DOI: 10.7554/elife.43318] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 04/19/2019] [Indexed: 11/13/2022] Open
Abstract
In complex biological systems, simple individual-level behavioral rules can give rise to emergent group-level behavior. While collective behavior has been well studied in cells and larger organisms, the mesoscopic scale is less understood, as it is unclear which sensory inputs and physical processes matter a priori. Here, we investigate collective feeding in the roundworm C. elegans at this intermediate scale, using quantitative phenotyping and agent-based modeling to identify behavioral rules underlying both aggregation and swarming-a dynamic phenotype only observed at longer timescales. Using fluorescence multi-worm tracking, we quantify aggregation in terms of individual dynamics and population-level statistics. Then we use agent-based simulations and approximate Bayesian inference to identify three key behavioral rules for aggregation: cluster-edge reversals, a density-dependent switch between crawling speeds, and taxis towards neighboring worms. Our simulations suggest that swarming is simply driven by local food depletion but otherwise employs the same behavioral mechanisms as the initial aggregation.
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Affiliation(s)
- Siyu Serena Ding
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Linus J Schumacher
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
- MRC Centre for Regenerative MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Avelino E Javer
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Robert G Endres
- Department of Life SciencesImperial College LondonLondonUnited Kingdom
| | - André EX Brown
- Instititue of Clinical SciencesImperial College LondonLondonUnited Kingdom
- MRC London Institute of Medical SciencesLondonUnited Kingdom
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23
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The type IV pilus assembly motor PilB is a robust hexameric ATPase with complex kinetics. Biochem J 2018; 475:1979-1993. [PMID: 29717025 DOI: 10.1042/bcj20180167] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/23/2018] [Accepted: 05/01/2018] [Indexed: 01/06/2023]
Abstract
The bacterial type IV pilus (T4P) is a versatile nanomachine that functions in pathogenesis, biofilm formation, motility, and horizontal gene transfer. T4P assembly is powered by the motor ATPase PilB which is proposed to hydrolyze ATP by a symmetrical rotary mechanism. This mechanism, which is deduced from the structure of PilB, is untested. Here, we report the first kinetic studies of the PilB ATPase, supporting co-ordination among the protomers of this hexameric enzyme. Analysis of the genome sequence of Chloracidobacterium thermophilum identified a pilB gene whose protein we then heterologously expressed. This PilB formed a hexamer in solution and exhibited highly robust ATPase activity. It displays complex steady-state kinetics with an incline followed by a decline over an ATP concentration range of physiological relevance. The incline is multiphasic and the decline signifies substrate inhibition. These observations suggest that variations in intracellular ATP concentrations may regulate T4P assembly and T4P-mediated functions in vivo in accordance with the physiological state of bacteria with unanticipated complexity. We also identified a mutant pilB gene in the genomic DNA of C. thermophilum from an enrichment culture. The mutant PilB variant, which is significantly less active, exhibited similar inhibition of its ATPase activity by high concentrations of ATP. Our findings here with the PilB ATPase from C. thermophilum provide the first line of biochemical evidence for the co-ordination among PilB protomers consistent with the symmetrical rotary model of catalysis based on structural studies.
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24
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Jain R, Sliusarenko O, Kazmierczak BI. Interaction of the cyclic-di-GMP binding protein FimX and the Type 4 pilus assembly ATPase promotes pilus assembly. PLoS Pathog 2017; 13:e1006594. [PMID: 28854278 PMCID: PMC5595344 DOI: 10.1371/journal.ppat.1006594] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 09/12/2017] [Accepted: 08/21/2017] [Indexed: 01/31/2023] Open
Abstract
Type IVa pili (T4P) are bacterial surface structures that enable motility, adhesion, biofilm formation and virulence. T4P are assembled by nanomachines that span the bacterial cell envelope. Cycles of T4P assembly and retraction, powered by the ATPases PilB and PilT, allow bacteria to attach to and pull themselves along surfaces, so-called “twitching motility”. These opposing ATPase activities must be coordinated and T4P assembly limited to one pole for bacteria to show directional movement. How this occurs is still incompletely understood. Herein, we show that the c-di-GMP binding protein FimX, which is required for T4P assembly in Pseudomonas aeruginosa, localizes to the leading pole of twitching bacteria. Polar FimX localization requires both the presence of T4P assembly machine proteins and the assembly ATPase PilB. PilB itself loses its polar localization pattern when FimX is absent. We use two different approaches to confirm that FimX and PilB interact in vivo and in vitro, and further show that point mutant alleles of FimX that do not bind c-di-GMP also do not interact with PilB. Lastly, we demonstrate that FimX positively regulates T4P assembly and twitching motility by promoting the activity of the PilB ATPase, and not by stabilizing assembled pili or by preventing PilT-mediated retraction. Mutated alleles of FimX that no longer bind c-di-GMP do not allow rapid T4P assembly in these assays. We propose that by virtue of its high-affinity for c-di-GMP, FimX can promote T4P assembly when intracellular levels of this cyclic nucleotide are low. As P. aeruginosa PilB is not itself a high-affinity c-di-GMP receptor, unlike many other assembly ATPases, FimX may play a key role in coupling T4P mediated motility and adhesion to levels of this second messenger. Type IV pili (T4P) are assembled on the surfaces of many bacterial pathogens and commensals through the action of specialized assembly machines whose components and structures are the subject of intense study. Repeated cycles of T4P assembly, attachment and retraction allow bacteria to move or “twitch” along surfaces, efficiently colonize and intoxicate host tissues, and elaborate multicellular structures such as biofilms. Assembly and retraction are powered by specific ATPases, PilB and PilT respectively, but the manner in which their activity is coordinated is still poorly understood. In this work, we provide evidence that a high-affinity c-di-GMP binding protein of Pseudomonas aeruginosa, FimX, interacts with the ATPase PilB and promotes PilB-dependent assembly of T4P. Live cell imaging of twitching bacteria shows that FimX localizes to the leading pole of motile P. aeruginosa and that its recruitment requires both components of the T4P assembly machine and the PilB ATPase. Our work highlights a novel regulatory strategy employed by P. aeruginosa to control assembly of this broadly conserved virulence factor.
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Affiliation(s)
- Ruchi Jain
- Department of Medicine (Infectious Diseases), Yale University, New Haven, Connecticut, United States of America
| | - Oleksii Sliusarenko
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Barbara I. Kazmierczak
- Department of Medicine (Infectious Diseases), Yale University, New Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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25
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Schumacher D, Søgaard-Andersen L. Regulation of Cell Polarity in Motility and Cell Division in Myxococcus xanthus. Annu Rev Microbiol 2017; 71:61-78. [PMID: 28525300 DOI: 10.1146/annurev-micro-102215-095415] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rod-shaped Myxococcus xanthus cells are polarized with proteins asymmetrically localizing to specific positions. This spatial organization is important for regulation of motility and cell division and changes over time. Dedicated protein modules regulate motility independent of the cell cycle, and cell division dependent on the cell cycle. For motility, a leading-lagging cell polarity is established that is inverted during cellular reversals. Establishment and inversion of this polarity are regulated hierarchically by interfacing protein modules that sort polarized motility proteins to the correct cell poles or cause their relocation between cell poles during reversals akin to a spatial toggle switch. For division, a novel self-organizing protein module that incorporates a ParA ATPase positions the FtsZ-ring at midcell. This review covers recent findings concerning the spatiotemporal regulation of motility and cell division in M. xanthus and illustrates how the study of diverse bacteria may uncover novel mechanisms involved in regulating bacterial cell polarity.
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Affiliation(s)
- Dominik Schumacher
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;
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