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Dersch S, Reimold C, Stoll J, Breddermann H, Heimerl T, Defeu Soufo HJ, Graumann PL. Polymerization of Bacillus subtilis MreB on a lipid membrane reveals lateral co-polymerization of MreB paralogs and strong effects of cations on filament formation. BMC Mol Cell Biol 2020; 21:76. [PMID: 33148162 PMCID: PMC7641798 DOI: 10.1186/s12860-020-00319-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/18/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND MreB is a bacterial ortholog of actin and forms mobile filaments underneath the cell membrane, perpendicular to the long axis of the cell, which play a crucial role for cell shape maintenance. We wished to visualize Bacillus subtilis MreB in vitro and therefore established a protocol to obtain monomeric protein, which could be polymerized on a planar membrane system, or associated with large membrane vesicles. RESULTS Using a planar membrane system and electron microscopy, we show that Bacillus subtilis MreB forms bundles of filaments, which can branch and fuse, with an average width of 70 nm. Fluorescence microscopy of non-polymerized YFP-MreB, CFP-Mbl and mCherry-MreBH proteins showed uniform binding to the membrane, suggesting that 2D diffusion along the membrane could facilitate filament formation. After addition of divalent magnesium and calcium ions, all three proteins formed highly disordered sheets of filaments that could split up or merge, such that at high protein concentration, MreB and its paralogs generated a network of filaments extending away from the membrane. Filament formation was positively affected by divalent ions and negatively by monovalent ions. YFP-MreB or CFP-Mbl also formed filaments between two adjacent membranes, which frequently has a curved appearance. New MreB, Mbl or MreBH monomers could add to the lateral side of preexisting filaments, and MreB paralogs co-polymerized, indicating direct lateral interaction between MreB paralogs. CONCLUSIONS Our data show that B. subtilis MreB paralogs do not easily form ordered filaments in vitro, possibly due to extensive lateral contacts, but can co-polymerise. Monomeric MreB, Mbl and MreBH uniformly bind to a membrane, and form irregular and frequently split up filamentous structures, facilitated by the addition of divalent ions, and counteracted by monovalent ions, suggesting that intracellular potassium levels may be one important factor to counteract extensive filament formation and filament splitting in vivo.
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Affiliation(s)
- Simon Dersch
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Christian Reimold
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Joshua Stoll
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | | | - Thomas Heimerl
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Biologie, Karl-von-Frisch-Straße 10, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Hervé Joel Defeu Soufo
- Department of Microsystems Engineering - IMTEK, University of Freiburg, 79110, Freiburg, Germany
| | - Peter L Graumann
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany. .,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany.
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Dersch S, Mehl J, Stuckenschneider L, Mayer B, Roth J, Rohrbach A, Graumann PL. Super-Resolution Microscopy and Single-Molecule Tracking Reveal Distinct Adaptive Dynamics of MreB and of Cell Wall-Synthesis Enzymes. Front Microbiol 2020; 11:1946. [PMID: 32973704 PMCID: PMC7468405 DOI: 10.3389/fmicb.2020.01946] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/23/2020] [Indexed: 11/23/2022] Open
Abstract
The movement of filamentous, actin-like MreB and of enzymes synthesizing the bacterial cell wall has been proposed to be highly coordinated. We have investigated the motion of MreB and of RodA and PbpH cell wall synthesis enzymes at 500 ms and at 20 ms time scales, allowing us to compare the motion of entire MreB filaments as well as of single molecules with that of the two synthesis proteins. While all three proteins formed assemblies that move with very similar trajectory orientation and with similar velocities, their trajectory lengths differed considerably, with PbpH showing shortest and MreB longest trajectories. These experiments suggest different on/off rates for RodA and PbpH at the putative peptidoglycan-extending machinery (PGEM), and during interaction with MreB filaments. Single molecule tracking revealed distinct slow-moving and freely diffusing populations of PbpH and RodA, indicating that they change between free diffusion and slow motion, indicating a dynamic interaction with the PGEM complex. Dynamics of MreB molecules and the orientation and speed of filaments changed markedly after induction of salt stress, while there was little change for RodA and PbpH single molecule dynamics. During the stress adaptation phase, cells continued to grow and extended the cell wall, while MreB formed fewer and more static filaments. Our results show that cell wall synthesis during stress adaptation occurs in a mode involving adaptation of MreB dynamics, and indicate that Bacillus subtilis cell wall extension involves an interplay of enzymes with distinct binding kinetics to sites of active synthesis.
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Affiliation(s)
- Simon Dersch
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Univetsität Marburg, Marburg, Germany
- Fachbereich Chemie, Philipps-Univetsität Marburg, Marburg, Germany
| | - Johanna Mehl
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering-IMTEK, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Lisa Stuckenschneider
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Univetsität Marburg, Marburg, Germany
- Fachbereich Chemie, Philipps-Univetsität Marburg, Marburg, Germany
| | - Benjamin Mayer
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Univetsität Marburg, Marburg, Germany
- Fachbereich Chemie, Philipps-Univetsität Marburg, Marburg, Germany
| | - Julian Roth
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering-IMTEK, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Alexander Rohrbach
- Laboratory for Bio- and Nano-Photonics, Department of Microsystems Engineering-IMTEK, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter L. Graumann
- SYNMIKRO, LOEWE-Zentrum für Synthetische Mikrobiologie, Philipps-Univetsität Marburg, Marburg, Germany
- Fachbereich Chemie, Philipps-Univetsität Marburg, Marburg, Germany
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3
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Deciphering Additional Roles for the EF-Tu, l-Asparaginase II and OmpT Proteins of Shiga Toxin-Producing Escherichia coli. Microorganisms 2020; 8:microorganisms8081184. [PMID: 32759661 PMCID: PMC7464798 DOI: 10.3390/microorganisms8081184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/31/2020] [Accepted: 08/01/2020] [Indexed: 12/14/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) causes outbreaks and sporadic cases of gastroenteritis. STEC O157:H7 is the most clinically relevant serotype in the world. The major virulence determinants of STEC O157:H7 are the Shiga toxins and the locus of enterocyte effacement. However, several accessory virulence factors, mainly outer membrane proteins (OMPs) that interact with the host cells may contribute to the virulence of this pathogen. Previously, the elongation factor thermo unstable (EF-Tu), l-asparaginase II and OmpT proteins were identified as antigens in OMP extracts of STEC. The known subcellular location of EF-Tu and l-asparaginase II are the cytoplasm and periplasm, respectively. Therefore, we investigate whether these two proteins may localize on the surface of STEC and, if so, what roles they have at this site. On the other hand, the OmpT protein, a well characterized protease, has been described as participating in the adhesion of extraintestinal pathogenic E. coli strains. Thus, we investigate whether OmpT has this role in STEC. Our results show that the EF-Tu and l-asparaginase II are secreted by O157:H7 and may also localize on the surface of this bacterium. EF-Tu was identified in outer membrane vesicles (OMVs), suggesting it as a possible export mechanism for this protein. Notably, we found that l-asparaginase II secreted by O157:H7 inhibits T-lymphocyte proliferation, but the role of EF-Tu at the surface of this bacterium remains to be elucidated. In the case of OmpT, we show its participation in the adhesion of O157:H7 to human epithelial cells. Thus, this study extends the knowledge of the pathogenic mechanisms of STEC.
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4
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Antimicrobial effects and membrane damage mechanism of blueberry (Vaccinium corymbosum L.) extract against Vibrio parahaemolyticus. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.107020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Hwang M, Han MH, Park HH, Choi H, Lee KY, Lee YJ, Kim JM, Cheong JH, Ryu JI, Min KW, Oh YH, Ko Y, Koh SH. LGR5 and Downstream Intracellular Signaling Proteins Play Critical Roles in the Cell Proliferation of Neuroblastoma, Meningioma and Pituitary Adenoma. Exp Neurobiol 2019; 28:628-641. [PMID: 31698554 PMCID: PMC6844835 DOI: 10.5607/en.2019.28.5.628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/09/2019] [Accepted: 09/19/2019] [Indexed: 12/15/2022] Open
Abstract
Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) has been reported to play critical roles in the proliferation of various cancer cells. However, the roles of LGR5 in brain tumors and the specific intracellular signaling proteins directly associated with it remain unknown. Expression of LGR5 was first measured in normal brain tissue, meningioma, and pituitary adenoma of humans. To identify the downstream signaling pathways of LGR5, siRNA-mediated knockdown of LGR5 was performed in SH-SY5Y neuroblastoma cells followed by proteomics analysis with 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In addition, the expression of LGR5-associated proteins was evaluated in LGR5-inhibited neuroblastoma cells and in human normal brain, meningioma, and pituitary adenoma tissue. Proteomics analysis showed 12 protein spots were significantly different in expression level (more than two-fold change) and subsequently identified by peptide mass fingerprinting. A protein association network was constructed from the 12 identified proteins altered by LGR5 knockdown. Direct and indirect interactions were identified among the 12 proteins. HSP 90-beta was one of the proteins whose expression was altered by LGR5 knockdown. Likewise, we observed decreased expression of proteins in the hnRNP subfamily following LGR5 knockdown. In addition, we have for the first time identified significantly higher hnRNP family expression in meningioma and pituitary adenoma compared to normal brain tissue. Taken together, LGR5 and its downstream signaling play critical roles in neuroblastoma and brain tumors such as meningioma and pituitary adenoma.
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Affiliation(s)
- Mina Hwang
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Myung-Hoon Han
- Department of Neurosurgery, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Hyun-Hee Park
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Hojin Choi
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Kyu-Yong Lee
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Young Joo Lee
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Jae Min Kim
- Department of Neurosurgery, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Jin Hwan Cheong
- Department of Neurosurgery, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Je Il Ryu
- Department of Neurosurgery, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Kyueng-Whan Min
- Department of Pathology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Young-Ha Oh
- Department of Pathology, Hanyang University Guri Hospital, Guri 11923, Korea
| | - Yong Ko
- Department of Neurosurgery, Hanyang University Medical Center, Seoul 04763, Korea
| | - Seong-Ho Koh
- Department of Neurology, Hanyang University Guri Hospital, Guri 11923, Korea.,Department of Translational Medicine, Hanyang University Graduate School of Biomedical Science & Engineering, Seoul 04763, Korea
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6
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Harvey KL, Jarocki VM, Charles IG, Djordjevic SP. The Diverse Functional Roles of Elongation Factor Tu (EF-Tu) in Microbial Pathogenesis. Front Microbiol 2019; 10:2351. [PMID: 31708880 PMCID: PMC6822514 DOI: 10.3389/fmicb.2019.02351] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/27/2019] [Indexed: 12/25/2022] Open
Abstract
Elongation factor thermal unstable Tu (EF-Tu) is a G protein that catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome inside living cells. Structural and biochemical studies have described the complex interactions needed to effect canonical function. However, EF-Tu has evolved the capacity to execute diverse functions on the extracellular surface of both eukaryote and prokaryote cells. EF-Tu can traffic to, and is retained on, cell surfaces where can interact with membrane receptors and with extracellular matrix on the surface of plant and animal cells. Our structural studies indicate that short linear motifs (SLiMs) in surface exposed, non-conserved regions of the molecule may play a key role in the moonlighting functions ascribed to this ancient, highly abundant protein. Here we explore the diverse moonlighting functions relating to pathogenesis of EF-Tu in bacteria and examine putative SLiMs on surface-exposed regions of the molecule.
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Affiliation(s)
- Kate L Harvey
- The ithree Institute, University of Technology Sydney, Ultimo, NSW, Australia
| | - Veronica M Jarocki
- The ithree Institute, University of Technology Sydney, Ultimo, NSW, Australia
| | - Ian G Charles
- Quadram Institute, Norwich, United Kingdom.,Norwich Medical School, Norwich, United Kingdom
| | - Steven P Djordjevic
- The ithree Institute, University of Technology Sydney, Ultimo, NSW, Australia
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7
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Mechanism of action of the moonlighting protein EfTu as a Substance P sensor in Bacillus cereus. Sci Rep 2019; 9:1304. [PMID: 30718605 PMCID: PMC6361937 DOI: 10.1038/s41598-018-37506-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/30/2018] [Indexed: 01/20/2023] Open
Abstract
The striking feature of the ubiquitous protein EfTu (Thermo unstable ribosomal Elongation factor) is its moonlighting (multifunctional) activity. Beyond its function at the ribosomal level it should be exported to the bacterial surface and act as an environmental sensor. In Bacillus cereus, and other cutaneous bacteria, it serves as a Substance P (SP) receptor and is essential for bacterial adaptation to the host. However, the modus operandi of EfTu as a bacterial sensor remains to be investigated. Studies realized by confocal and transmission electron microscopy revealed that, in the absence of an exogenous signal, EfTu is not exposed on the bacterial surface but is recruited under the effect of SP. In addition, SP acts as a transcriptional regulator of the tuf gene encoding for EfTu. As observed using gadolinium chloride, an inhibitor of membrane mechanosensitive channels (Msc), Msc control EfTu export and subsequently the bacterial response to SP both in terms of cytotoxicity and biofilm formation activity. Microscale thermophoresis revealed that in response to SP, EfTu can form homopolymers. This event should occur after EfTu export and, as shown by proteo-liposome reconstruction studies, SP appears to promote EfTu polymers association to the membrane, leading subsequently to the bacterial response. Molecular modeling suggests that this mechanism should involve EfTu unfolding and insertion into the bacterial cytoplasmic membrane, presumably through formation of homopolymers. This study is unraveling the original mechanism action of EfTu as a bacterial sensor but also reveals that this protein should have a broader role, including in eukaryotes.
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8
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Abstract
Bacillus subtilis is the best described member of the Gram positive bacteria. It is a typical rod shaped bacterium and grows by elongation in its long axis, before dividing at mid cell to generate two similar daughter cells. B. subtilis is a particularly interesting model for cell cycle studies because it also carries out a modified, asymmetrical division during endospore formation, which can be simply induced by starvation. Cell growth occurs strictly by elongation of the rod, which maintains a constant diameter at all growth rates. This process involves expansion of the cell wall, requiring intercalation of new peptidoglycan and teichoic acid material, as well as controlled hydrolysis of existing wall material. Actin-like MreB proteins are the key spatial regulators that orchestrate the plethora of enzymes needed for cell elongation, many of which are thought to assemble into functional complexes called elongasomes. Cell division requires a switch in the orientation of cell wall synthesis and is organised by a tubulin-like protein FtsZ. FtsZ forms a ring-like structure at the site of impending division, which is specified by a range of mainly negative regulators. There it recruits a set of dedicated division proteins to form a structure called the divisome, which brings about the process of division. During sporulation, both the positioning and fine structure of the division septum are altered, and again, several dedicated proteins that contribute specifically to this process have been identified. This chapter summarises our current understanding of elongation and division in B. subtilis, with particular emphasis on the cytoskeletal proteins MreB and FtsZ, and highlights where the major gaps in our understanding remain.
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Harms A, Stanger FV, Dehio C. Biological Diversity and Molecular Plasticity of FIC Domain Proteins. Annu Rev Microbiol 2016; 70:341-60. [PMID: 27482742 DOI: 10.1146/annurev-micro-102215-095245] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ubiquitous proteins with FIC (filamentation induced by cyclic AMP) domains use a conserved enzymatic machinery to modulate the activity of various target proteins by posttranslational modification, typically AMPylation. Following intensive study of the general properties of FIC domain catalysis, diverse molecular activities and biological functions of these remarkably versatile proteins are now being revealed. Here, we review the biological diversity of FIC domain proteins and summarize the underlying structure-function relationships. The original and most abundant genuine bacterial FIC domain proteins are toxins that use diverse molecular activities to interfere with bacterial physiology in various, yet ill-defined, biological contexts. Host-targeted virulence factors have evolved repeatedly out of this pool by exaptation of the enzymatic FIC domain machinery for the manipulation of host cell signaling in favor of bacterial pathogens. The single human FIC domain protein HypE (FICD) has a specific function in the regulation of protein stress responses.
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Affiliation(s)
- Alexander Harms
- Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland; , ,
| | - Frédéric V Stanger
- Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland; , , .,Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.,*Current address: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Christoph Dehio
- Focal Area Infection Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland; , ,
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11
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Abstract
Traditionally eukaryotes exclusive cytoskeleton has been found in bacteria and other prokaryotes. FtsZ, MreB and CreS are bacterial counterpart of eukaryotic tubulin, actin filaments and intermediate filaments, respectively. FtsZ can assemble to a Z-ring at the cell division site, regulate bacterial cell division; MreB can form helical structure, and involve in maintaining cell shape, regulating chromosome segregation; CreS, found in Caulobacter crescentus (C. crescentus), can form curve or helical filaments in intracellular membrane. CreS is crucial for cell morphology maintenance. There are also some prokaryotic unique cytoskeleton components playing crucial roles in cell division, chromosome segregation and cell morphology. The cytoskeleton components of Mycobacterium tuberculosis (M. tuberculosis), together with their dynamics during exposure to antibiotics are summarized in this article to provide insights into the unique organization of this formidable pathogen and druggable targets for new antibiotics.
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Affiliation(s)
- Huan Wang
- a Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University , Chongqing , China
| | - Longxiang Xie
- a Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University , Chongqing , China
| | - Hongping Luo
- a Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University , Chongqing , China
| | - Jianping Xie
- a Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University , Chongqing , China
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Treuner-Lange A, Macia E, Guzzo M, Hot E, Faure LM, Jakobczak B, Espinosa L, Alcor D, Ducret A, Keilberg D, Castaing JP, Lacas Gervais S, Franco M, Søgaard-Andersen L, Mignot T. The small G-protein MglA connects to the MreB actin cytoskeleton at bacterial focal adhesions. J Cell Biol 2015; 210:243-56. [PMID: 26169353 PMCID: PMC4508894 DOI: 10.1083/jcb.201412047] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/09/2015] [Indexed: 12/27/2022] Open
Abstract
In Myxococcus xanthus the gliding motility machinery is assembled at the leading cell pole to form focal adhesions, translocated rearward to propel the cell, and disassembled at the lagging pole. We show that MglA, a Ras-like small G-protein, is an integral part of this machinery. In this function, MglA stimulates the assembly of the motility complex by directly connecting it to the MreB actin cytoskeleton. Because the nucleotide state of MglA is regulated spatially and MglA only binds MreB in the guanosine triphosphate-bound form, the motility complexes are assembled at the leading pole and dispersed at the lagging pole where the guanosine triphosphatase activating protein MglB disrupts the MglA-MreB interaction. Thus, MglA acts as a nucleotide-dependent molecular switch to regulate the motility machinery spatially. The function of MreB in motility is independent of its function in peptidoglycan synthesis, representing a coopted function. Our findings highlight a new function for the MreB cytoskeleton and suggest that G-protein-cytoskeleton interactions are a universally conserved feature.
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Affiliation(s)
- Anke Treuner-Lange
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Eric Macia
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, 06560 Valbonne, France
| | - Mathilde Guzzo
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
| | - Edina Hot
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Laura M Faure
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
| | - Beata Jakobczak
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Leon Espinosa
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
| | - Damien Alcor
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, 06560 Valbonne, France
| | - Adrien Ducret
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
| | - Daniela Keilberg
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Jean Philippe Castaing
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
| | - Sandra Lacas Gervais
- Centre Commun de Microscopie Appliquée, Université de Nice Sophia Antipolis, 06103 Nice, France
| | - Michel Franco
- Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275 Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, 06560 Valbonne, France
| | | | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, UMR 7283 Centre National de la Recherche Scientifique, Aix Marseille University, 13009 Marseille, France
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