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Dunn CM, Foust D, Gao Y, Biteen JS, Shaw SL, Kearns DB. Nascent flagellar basal bodies are immobilized by rod assembly in Bacillus subtilis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.02.606393. [PMID: 39211283 PMCID: PMC11360914 DOI: 10.1101/2024.08.02.606393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Flagella are complex, trans-envelope nanomachines that localize to species- specific cellular addresses. Here we study the localization dynamics of the earliest stage of basal body formation in Bacillus subtilis using a fluorescent fusion to the C-ring protein FliM. We find that B. subtilis basal bodies do not exhibit dynamic subunit exchange and are largely stationary at steady state, consistent with flagellar assembly through the peptidoglycan. Rare basal bodies were observed to be mobile however, and the frequency of basal body mobility is elevated both early in basal body assembly and when the rod is mutated. Thus, basal body mobility is a precursor to patterning and we propose that rod polymerization probes the peptidoglycan superstructure for pores of sufficient diameter that permit rod completion. Furthermore, mutation of the rod also disrupts basal body patterning in a way that phenocopies mutation of the cytoplasmic flagellar patterning protein FlhF. We infer that conformational changes in the basal body exchange information between rod synthesis and the cytoplasmic patterning proteins to restrict assembly at certain pores established by a grid-like pattern pre-existent in the peptidoglycan itself. IMPORTANCE Bacteria insert flagella in a species-specific pattern on the cell body, but how patterns are achieved is poorly understood. In bacteria with a single polar flagellum, a marker protein localizes to the cell pole and nucleates the assembly of the flagellum at that site. Bacillus subtilis assembles ∼15 flagella over the length of the cell body in a grid-like pattern and lacks all proteins associated with targeted assembly in polarly flagellated bacteria. Here we show that B. subtilis basal bodies are mobile soon after assembly and become immobilized when the flagellar rod transits the peptidoglycan wall. Moreover, defects in the flagellar rod lead to an asymmetric distribution of flagella with respect to the midcell. We conclude that the patterning of flagella is different in B. subtilis , and we infer that the B. subtilis rod probes the peptidoglycan for holes that can accommodate the machine.
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2
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Dornes A, Schmidt LM, Mais CN, Hook JC, Pané-Farré J, Kressler D, Thormann K, Bange G. Polar confinement of a macromolecular machine by an SRP-type GTPase. Nat Commun 2024; 15:5797. [PMID: 38987236 PMCID: PMC11236974 DOI: 10.1038/s41467-024-50274-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/05/2024] [Indexed: 07/12/2024] Open
Abstract
The basal structure of the bacterial flagellum includes a membrane embedded MS-ring (formed by multiple copies of FliF) and a cytoplasmic C-ring (composed of proteins FliG, FliM and FliN). The SRP-type GTPase FlhF is required for directing the initial flagellar protein FliF to the cell pole, but the mechanisms are unclear. Here, we show that FlhF anchors developing flagellar structures to the polar landmark protein HubP/FimV, thereby restricting their formation to the cell pole. Specifically, the GTPase domain of FlhF interacts with HubP, while a structured domain at the N-terminus of FlhF binds to FliG. FlhF-bound FliG subsequently engages with the MS-ring protein FliF. Thus, the interaction of FlhF with HubP and FliG recruits a FliF-FliG complex to the cell pole. In addition, the modulation of FlhF activity by the MinD-type ATPase FlhG controls the interaction of FliG with FliM-FliN, thereby regulating the progression of flagellar assembly at the pole.
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Affiliation(s)
- Anita Dornes
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany
| | - Lisa Marie Schmidt
- Justus-Liebig-Universität, Department of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26, 35392, Giessen, Germany
| | - Christopher-Nils Mais
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany
| | - John C Hook
- Justus-Liebig-Universität, Department of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26, 35392, Giessen, Germany
| | - Jan Pané-Farré
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany
| | - Dieter Kressler
- University of Fribourg, Department of Biology, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Kai Thormann
- Justus-Liebig-Universität, Department of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26, 35392, Giessen, Germany.
| | - Gert Bange
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Hans-Meerwein-Strasse 6, C07, 35043, Marburg, Germany.
- Max-Planck-Institute for terrestrial Microbiology, Molecular Physiology of Microbes, Karl-von-Frisch Strasse 14, 35043, Marburg, Germany.
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3
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Dornes A, Mais CN, Bange G. Structure of the GDP-bound state of the SRP GTPase FlhF. Acta Crystallogr F Struct Biol Commun 2024; 80:53-58. [PMID: 38376823 PMCID: PMC10910532 DOI: 10.1107/s2053230x24000979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/27/2024] [Indexed: 02/21/2024] Open
Abstract
The GTPase FlhF, a signal recognition particle (SRP)-type enzyme, is pivotal for spatial-numerical control and bacterial flagella assembly across diverse species, including pathogens. This study presents the X-ray structure of FlhF in its GDP-bound state at a resolution of 2.28 Å. The structure exhibits the classical N- and G-domain fold, consistent with related SRP GTPases such as Ffh and FtsY. Comparative analysis with GTP-loaded FlhF elucidates the conformational changes associated with GTP hydrolysis. These topological reconfigurations are similarly evident in Ffh and FtsY, and play a pivotal role in regulating the functions of these hydrolases.
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Affiliation(s)
- Anita Dornes
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, University of Marburg, Karl-von-Frisch-Strasse 14, 35043 Marburg, Germany
| | - Christopher-Nils Mais
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, University of Marburg, Karl-von-Frisch-Strasse 14, 35043 Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, University of Marburg, Karl-von-Frisch-Strasse 14, 35043 Marburg, Germany
- Molecular Physiology of Microbes, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 14, 35043 Marburg, Germany
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4
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Korf L, Ye X, Vogt MS, Steinchen W, Watad M, van der Does C, Tourte M, Sivabalasarma S, Albers SV, Essen LO. Archaeal GPN-loop GTPases involve a lock-switch-rock mechanism for GTP hydrolysis. mBio 2023; 14:e0085923. [PMID: 37962382 PMCID: PMC10746158 DOI: 10.1128/mbio.00859-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/05/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE GPN-loop GTPases have been found to be crucial for eukaryotic RNA polymerase II assembly and nuclear trafficking. Despite their ubiquitous occurrence in eukaryotes and archaea, the mechanism by which these GTPases mediate their function is unknown. Our study on an archaeal representative from Sulfolobus acidocaldarius showed that these dimeric GTPases undergo large-scale conformational changes upon GTP hydrolysis, which can be summarized as a lock-switch-rock mechanism. The observed requirement of SaGPN for motility appears to be due to its large footprint on the archaeal proteome.
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Affiliation(s)
- Lukas Korf
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Xing Ye
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Marian S. Vogt
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Wieland Steinchen
- Department of Chemistry, Philipps University, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Strasse, Marburg, Germany
| | - Mohamed Watad
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Chris van der Does
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Maxime Tourte
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Shamphavi Sivabalasarma
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Sonja-Verena Albers
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
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5
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Gibson KH, Botting JM, Al-Otaibi N, Maitre K, Bergeron J, Starai VJ, Hoover TR. Control of the flagellation pattern in Helicobacter pylori by FlhF and FlhG. J Bacteriol 2023; 205:e0011023. [PMID: 37655916 PMCID: PMC10521351 DOI: 10.1128/jb.00110-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/06/2023] [Indexed: 09/02/2023] Open
Abstract
FlhF and FlhG control the location and number of flagella, respectively, in many polar-flagellated bacteria. The roles of FlhF and FlhG are not well characterized in bacteria that have multiple polar flagella, such as Helicobacter pylori. Deleting flhG in H. pylori shifted the flagellation pattern where most cells had approximately four flagella to a wider and more even distribution in flagellar number. As reported in other bacteria, deleting flhF in H. pylori resulted in reduced motility, hypoflagellation, and the improper localization of flagella to nonpolar sites. Motile variants of H. pylori ∆flhF mutants that had a higher proportion of flagella localizing correctly to the cell pole were isolated, but we were unable to identify the genetic determinants responsible for the increased localization of flagella to the cell pole. One motile variant though produced more flagella than the ΔflhF parental strain, which apparently resulted from a missense mutation in fliF (encodes the MS ring protein), which changed Asn-255 to aspartate. Recombinant FliFN255D, but not recombinant wild-type FliF, formed ordered ring-like assemblies in vitro that were ~50 nm wide and displayed the MS ring architecture. We infer from these findings that the FliFN225D variant forms the MS ring more effectively in vivo in the absence of FlhF than wild-type FliF. IMPORTANCE Helicobacter pylori colonizes the human stomach where it can cause a variety of diseases, including peptic ulcer disease and gastric cancer. H. pylori uses flagella for motility, which is required for host colonization. FlhG and FlhF control the flagellation patterns in many bacteria. We found that in H. pylori, FlhG ensures that cells have approximately equal number of flagella and FlhF is needed for flagellum assembly and localization. FlhF is proposed to facilitate the assembly of FliF into the MS ring, which is one of the earliest structures formed in flagellum assembly. We identified a FliF variant that assembles the MS ring in the absence of FlhF, which supports the proposed role of FlhF in facilitating MS ring assembly.
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Affiliation(s)
| | - Jack M. Botting
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Natalie Al-Otaibi
- Randall Division of Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Kriti Maitre
- Randall Division of Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Julien Bergeron
- Randall Division of Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Vincent J. Starai
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Timothy R. Hoover
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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6
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Schwan M, Khaledi A, Willger S, Papenfort K, Glatter T, Häußler S, Thormann KM. FlrA-independent production of flagellar proteins is required for proper flagellation in Shewanella putrefaciens. Mol Microbiol 2022; 118:670-682. [PMID: 36285560 DOI: 10.1111/mmi.14993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 01/18/2023]
Abstract
Flagella are multiprotein complexes whose assembly and positioning require complex spatiotemporal control. Flagellar assembly is thought to be controlled by several transcriptional tiers, which are mediated through various master regulators. Here, we revisited the regulation of flagellar genes in polarly flagellated gammaproteobacteria by the regulators FlrA, RpoN (σ54 ) and FliA (σ28 ) in Shewanella putrefaciens CN-32 at the transcript and protein level. We found that a number of regulatory and structural proteins were present in the absence of the main regulators, suggesting that initiation of flagella assembly and motor activation relies on the abundance control of only a few structural key components that are required for the formation of the MS- and C-ring and the flagellar type III secretion system. We identified FlrA-independent promoters driving expression of the regulators of flagellar number and positioning, FlhF and FlhG. Reduction of the gene expression levels from these promoters resulted in the emergence of hyperflagellation. This finding indicates that basal expression is required to adjust the flagellar counter in Shewanella. This is adding a deeper layer to the regulation of flagellar synthesis and assembly.
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Affiliation(s)
- Meike Schwan
- Institute of Microbiology and Molecular Biology, Justus-Liebig-Universität, Giessen, Germany
| | - Ariane Khaledi
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sven Willger
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Kai Papenfort
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany
| | - Timo Glatter
- Max Planck Institute for Terrestrial Microbiology, Mass Spectrometry and Proteomics, Marburg, Germany
| | - Susanne Häußler
- Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Kai M Thormann
- Institute of Microbiology and Molecular Biology, Justus-Liebig-Universität, Giessen, Germany
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7
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Homma M, Mizuno A, Hao Y, Kojima S. Functional analysis of the N-terminal region of Vibrio FlhG, a MinD-type ATPase in flagellar number control. J Biochem 2022; 172:99-107. [DOI: 10.1093/jb/mvac047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/17/2022] [Indexed: 11/12/2022] Open
Abstract
Summary
GTPase FlhF and ATPase FlhG are two key factors involved in regulating the flagellum number in Vibrio alginolyticus. FlhG is a paralog of the Escherichia coli cell division regulator MinD and has a longer N-terminal region than MinD with a conserved DQAxxLR motif. The deletion of this N-terminal region or a Q9A mutation in the DQAxxLR motif prevents FlhG from activating the GTPase activity of FlhF in vitro and causes a multi-flagellation phenotype. The mutant FlhG proteins, especially the N-terminally deleted variant, was remarkably reduced compared to that of the wild-type protein in vivo. When the mutant FlhG was expressed at the same level as the wild-type FlhG, the number of flagella was restored to the wild-type level. Once synthesized in Vibrio cells, the N-terminal region mutation in FlhG seems not to affect the protein stability. We speculated that the flhG translation efficiency is decreased by N-terminal mutation. Our results suggest that the N-terminal region of FlhG controls the number of flagella by adjusting the FlhF activity and the amount of FlhG in vivo. We speculate that the regulation by FlhG, achieved through transcription by the master regulator FlaK, is affected by the mutations, resulting in reduced flagellar formation by FlhF.
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Affiliation(s)
- Michio Homma
- Graduate School of Science Division of Biological Science, , Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Akira Mizuno
- Graduate School of Science Division of Biological Science, , Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuxi Hao
- Graduate School of Science Division of Biological Science, , Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Seiji Kojima
- Graduate School of Science Division of Biological Science, , Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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8
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Han X, Li J, Zhao Y, Zhang Z, Jiang H, Wang J, Feng X, Zhang Y, Du Z, Wu X, Chen Q, Qi Z. Integrated transcriptomic and proteomic characterization of a chromosome segment substitution line reveals a new regulatory network controlling the seed storage profile of soybean. Food Energy Secur 2022. [DOI: 10.1002/fes3.381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Xue Han
- College of Agriculture Northeast Agricultural University Harbin China
- Heilongjiang Academy of Land Reclamation Sciences Harbin China
| | - Jiapeng Li
- College of Agriculture Northeast Agricultural University Harbin China
| | - Yabin Zhao
- College of Agriculture Northeast Agricultural University Harbin China
| | - Zhanguo Zhang
- College of Agriculture Northeast Agricultural University Harbin China
| | - Hongwei Jiang
- Soybean Research Institute Jilin Academy of Agricultural Sciences Changchun China
| | - Jinxing Wang
- Suihua Branch Institute, HeiLongJiang Academy of Agricultural Sciences Suihua China
| | - Xuezhen Feng
- College of Agriculture Northeast Agricultural University Harbin China
| | - Yu Zhang
- College of Agriculture Northeast Agricultural University Harbin China
| | - Ziyue Du
- College of Agriculture Northeast Agricultural University Harbin China
| | - Xiaoxia Wu
- College of Agriculture Northeast Agricultural University Harbin China
| | - Qingshan Chen
- College of Agriculture Northeast Agricultural University Harbin China
| | - Zhaoming Qi
- College of Agriculture Northeast Agricultural University Harbin China
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9
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Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun 2022; 13:1069. [PMID: 35217658 PMCID: PMC8881573 DOI: 10.1038/s41467-022-28675-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 02/07/2022] [Indexed: 11/08/2022] Open
Abstract
The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli. Bacterial responses to nutrient limitation and other stress conditions are often modulated by the nucleotide-based second messenger (p)ppGpp. Here, the authors show that (p)ppGpp inhibits the SRP membrane-protein insertion and secretion pathway by binding to GTPases Ffh and FtsY.
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10
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Fule L, Halifa R, Fontana C, Sismeiro O, Legendre R, Varet H, Coppée JY, Murray GL, Adler B, Hendrixson DR, Buschiazzo A, Guo S, Liu J, Picardeau M. Role of the major determinant of polar flagellation FlhG in the endoflagella-containing spirochete Leptospira. Mol Microbiol 2021; 116:1392-1406. [PMID: 34657338 DOI: 10.1111/mmi.14831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/06/2021] [Accepted: 10/13/2021] [Indexed: 01/31/2023]
Abstract
Spirochetes can be distinguished from other bacteria by their spiral-shaped morphology and subpolar periplasmic flagella. This study focused on FlhF and FlhG, which control the spatial and numerical regulation of flagella in many exoflagellated bacteria, in the spirochete Leptospira. In contrast to flhF which seems to be essential in Leptospira, we demonstrated that flhG- mutants in both the saprophyte L. biflexa and the pathogen L. interrogans were less motile than the wild-type strains in gel-like environments but not hyperflagellated as reported previously in other bacteria. Cryo-electron tomography revealed that the distance between the flagellar basal body and the tip of the cell decreased significantly in the flhG- mutant in comparison to wild-type and complemented strains. Additionally, comparative transcriptome analyses of L. biflexa flhG- and wild-type strains showed that FlhG acts as a negative regulator of transcription of some flagellar genes. We found that the L. interrogans flhG- mutant was attenuated for virulence in the hamster model. Cross-species complementation also showed that flhG is not interchangeable between species. Our results indicate that FlhF and FlhG in Leptospira contribute to governing cell motility but our data support the hypothesis that FlhF and FlhG function differently in each bacterial species, including among spirochetes.
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Affiliation(s)
- Lenka Fule
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Université de Paris, Paris, France
| | - Ruben Halifa
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
| | - Celia Fontana
- Boehringer Ingelheim Santé Animale, Saint Priest, France
| | - Odile Sismeiro
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Rachel Legendre
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Hugo Varet
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Jean-Yves Coppée
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Gerald L Murray
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Ben Adler
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Alejandro Buschiazzo
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Shuaiqi Guo
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jun Liu
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mathieu Picardeau
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
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11
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Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N. Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle. Cell Rep 2021; 36:109350. [PMID: 34260909 PMCID: PMC8330425 DOI: 10.1016/j.celrep.2021.109350] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/23/2021] [Accepted: 06/15/2021] [Indexed: 11/26/2022] Open
Abstract
Co-translational protein targeting to membranes by the signal recognition particle (SRP) is a universally conserved pathway from bacteria to humans. In mammals, SRP and its receptor (SR) have many additional RNA features and protein components compared to the bacterial system, which were recently shown to play regulatory roles. Due to its complexity, the mammalian SRP targeting process is mechanistically not well understood. In particular, it is not clear how SRP recognizes translating ribosomes with exposed signal sequences and how the GTPase activity of SRP and SR is regulated. Here, we present electron cryo-microscopy structures of SRP and SRP·SR in complex with the translating ribosome. The structures reveal the specific molecular interactions between SRP and the emerging signal sequence and the elements that regulate GTPase activity of SRP·SR. Our results suggest the molecular mechanism of how eukaryote-specific elements regulate the early and late stages of SRP-dependent protein targeting. Jomaa et al. present cryo-EM structures of mammalian SRP, SRP receptor, and the translating ribosome. The structures reveal the role of eukaryotic-specific features involved in regulating early and late stages of co-translational protein targeting to the endoplasmic reticulum and suggest a model for cargo recognition and handover.
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Affiliation(s)
- Ahmad Jomaa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
| | - Simon Eitzinger
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Zikun Zhu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Sowmya Chandrasekar
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Kan Kobayashi
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
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12
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Arroyo-Pérez EE, Ringgaard S. Interdependent Polar Localization of FlhF and FlhG and Their Importance for Flagellum Formation of Vibrio parahaemolyticus. Front Microbiol 2021; 12:655239. [PMID: 33815347 PMCID: PMC8009987 DOI: 10.3389/fmicb.2021.655239] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 02/23/2021] [Indexed: 11/14/2022] Open
Abstract
Failure of the cell to properly regulate the number and intracellular positioning of their flagella, has detrimental effects on the cells’ swimming ability. The flagellation pattern of numerous bacteria is regulated by the NTPases FlhF and FlhG. In general, FlhG controls the number of flagella produced, whereas FlhF coordinates the position of the flagella. In the human pathogen Vibrio parahaemolyticus, its single flagellum is positioned and formed at the old cell pole. Here, we describe the spatiotemporal localization of FlhF and FlhG in V. parahaemolyticus and their effect on swimming motility. Absence of either FlhF or FlhG caused a significant defect in swimming ability, resulting in absence of flagella in a ΔflhF mutant and an aberrant flagellated phenotype in ΔflhG. Both proteins localized to the cell pole in a cell cycle-dependent manner, but displayed different patterns of localization throughout the cell cycle. FlhF transitioned from a uni- to bi-polar localization, as observed in other polarly flagellated bacteria. Localization of FlhG was strictly dependent on the cell pole-determinant HubP, while polar localization of FlhF was HubP independent. Furthermore, localization of FlhF and FlhG was interdependent and required for each other’s proper intracellular localization and recruitment to the cell pole. In the absence of HubP or FlhF, FlhG forms non-polar foci in the cytoplasm of the cell, suggesting the possibility of a secondary localization site within the cell besides its recruitment to the cell poles.
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Affiliation(s)
- Erick Eligio Arroyo-Pérez
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.,Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Simon Ringgaard
- Department of Biology I, Microbiology, Ludwig-Maximilians-Universität München, Munich, Germany
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13
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Harris AJ, Goldman AD. The very early evolution of protein translocation across membranes. PLoS Comput Biol 2021; 17:e1008623. [PMID: 33684113 PMCID: PMC7987157 DOI: 10.1371/journal.pcbi.1008623] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 03/23/2021] [Accepted: 12/10/2020] [Indexed: 11/18/2022] Open
Abstract
In this study, we used a computational approach to investigate the early evolutionary history of a system of proteins that, together, embed and translocate other proteins across cell membranes. Cell membranes comprise the basis for cellularity, which is an ancient, fundamental organizing principle shared by all organisms and a key innovation in the evolution of life on Earth. Two related requirements for cellularity are that organisms are able to both embed proteins into membranes and translocate proteins across membranes. One system that accomplishes these tasks is the signal recognition particle (SRP) system, in which the core protein components are the paralogs, FtsY and Ffh. Complementary to the SRP system is the Sec translocation channel, in which the primary channel-forming protein is SecY. We performed phylogenetic analyses that strongly supported prior inferences that FtsY, Ffh, and SecY were all present by the time of the last universal common ancestor of life, the LUCA, and that the ancestor of FtsY and Ffh existed before the LUCA. Further, we combined ancestral sequence reconstruction and protein structure and function prediction to show that the LUCA had an SRP system and Sec translocation channel that were similar to those of extant organisms. We also show that the ancestor of Ffh and FtsY that predated the LUCA was more similar to FtsY than Ffh but could still have comprised a rudimentary protein translocation system on its own. Duplication of the ancestor of FtsY and Ffh facilitated the specialization of FtsY as a membrane bound receptor and Ffh as a cytoplasmic protein that could bind nascent proteins with specific membrane-targeting signal sequences. Finally, we analyzed amino acid frequencies in our ancestral sequence reconstructions to infer that the ancestral Ffh/FtsY protein likely arose prior to or just after the completion of the canonical genetic code. Taken together, our results offer a window into the very early evolutionary history of cellularity.
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Affiliation(s)
- AJ Harris
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Department of Biology, Oberlin College and Conservatory, K123 Science Center, Oberlin, Ohio, United States of America
| | - Aaron David Goldman
- Department of Biology, Oberlin College and Conservatory, K123 Science Center, Oberlin, Ohio, United States of America
- Blue Marble Space Institute of Science, Seattle, Washington, United States of America
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14
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Abidi W, Zouhir S, Caleechurn M, Roche S, Krasteva PV. Architecture and regulation of an enterobacterial cellulose secretion system. SCIENCE ADVANCES 2021; 7:7/5/eabd8049. [PMID: 33563593 PMCID: PMC7840130 DOI: 10.1126/sciadv.abd8049] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 12/08/2020] [Indexed: 05/03/2023]
Abstract
Many free-living and pathogenic enterobacteria secrete biofilm-promoting cellulose using a multicomponent, envelope-embedded Bcs secretion system under the control of intracellular second messenger c-di-GMP. The molecular understanding of system assembly and cellulose secretion has been largely limited to the crystallographic studies of a distantly homologous BcsAB synthase tandem and a low-resolution reconstruction of an assembled macrocomplex that encompasses most of the inner membrane and cytosolic subunits and features an atypical layered architecture. Here, we present cryo-EM structures of the assembled Bcs macrocomplex, as well as multiple crystallographic snapshots of regulatory Bcs subcomplexes. The structural and functional data uncover the mechanism of asymmetric secretion system assembly and periplasmic crown polymerization and reveal unexpected subunit stoichiometry, multisite c-di-GMP recognition, and ATP-dependent regulation.
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Affiliation(s)
- Wiem Abidi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif- sur-Yvette, France
- "Structural Biology of Biofilms" Group, European Institute of Chemistry and Biology (IECB), 33600 Pessac, France
- CBMN UMR 5248 CNRS, University of Bordeaux, 33600 Pessac, France
| | - Samira Zouhir
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif- sur-Yvette, France
- "Structural Biology of Biofilms" Group, European Institute of Chemistry and Biology (IECB), 33600 Pessac, France
- CBMN UMR 5248 CNRS, University of Bordeaux, 33600 Pessac, France
| | - Meryem Caleechurn
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif- sur-Yvette, France
| | - Stéphane Roche
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif- sur-Yvette, France
| | - Petya Violinova Krasteva
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91198 Gif- sur-Yvette, France.
- "Structural Biology of Biofilms" Group, European Institute of Chemistry and Biology (IECB), 33600 Pessac, France
- CBMN UMR 5248 CNRS, University of Bordeaux, 33600 Pessac, France
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15
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Han R, Fang J, Jiang J, Gaidamakova EK, Tkavc R, Daly MJ, Contreras LM. Signal Recognition Particle RNA Contributes to Oxidative Stress Response in Deinococcus radiodurans by Modulating Catalase Localization. Front Microbiol 2020; 11:613571. [PMID: 33391243 PMCID: PMC7775534 DOI: 10.3389/fmicb.2020.613571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022] Open
Abstract
The proper functioning of many proteins requires their transport to the correct cellular compartment or their secretion. Signal recognition particle (SRP) is a major protein transport pathway responsible for the co-translational movement of integral membrane proteins as well as periplasmic proteins. Deinococcus radiodurans is a ubiquitous bacterium that expresses a complex phenotype of extreme oxidative stress resistance, which depends on proteins involved in DNA repair, metabolism, gene regulation, and antioxidant defense. These proteins are located extracellularly or subcellularly, but the molecular mechanism of protein localization in D. radiodurans to manage oxidative stress response remains unexplored. In this study, we characterized the SRP complex in D. radiodurans R1 and showed that the knockdown (KD) of the SRP RNA (Qpr6) reduced bacterial survival under hydrogen peroxide and growth under chronic ionizing radiation. Through LC-mass spectrometry (MS/MS) analysis, we detected 162 proteins in the periplasm of wild-type D. radiodurans, of which the transport of 65 of these proteins to the periplasm was significantly reduced in the Qpr6 KD strain. Through Western blotting, we further demonstrated the localization of the catalases in D. radiodurans, DR_1998 (KatE1) and DR_A0259 (KatE2), in both the cytoplasm and periplasm, respectively, and showed that the accumulation of KatE1 and KatE2 in the periplasm was reduced in the SRP-defective strains. Collectively, this study establishes the importance of the SRP pathway in the survival and the transport of antioxidant proteins in D. radiodurans under oxidative stress.
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Affiliation(s)
- Runhua Han
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Jaden Fang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Jessie Jiang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Elena K Gaidamakova
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Rok Tkavc
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.,Uniformed Services University of the Health Sciences, Department of Microbiology and Immunology, Bethesda, MD, United States
| | - Michael J Daly
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular & Molecular Biology, The University of Texas at Austin, Austin, TX, United States
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16
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An ATP-dependent partner switch links flagellar C-ring assembly with gene expression. Proc Natl Acad Sci U S A 2020; 117:20826-20835. [PMID: 32788349 DOI: 10.1073/pnas.2006470117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacterial flagella differ in their number and spatial arrangement. In many species, the MinD-type ATPase FlhG (also YlxH/FleN) is central to the numerical control of bacterial flagella, and its deletion in polarly flagellated bacteria typically leads to hyperflagellation. The molecular mechanism underlying this numerical control, however, remains enigmatic. Using the model species Shewanella putrefaciens, we show that FlhG links assembly of the flagellar C ring with the action of the master transcriptional regulator FlrA (named FleQ in other species). While FlrA and the flagellar C-ring protein FliM have an overlapping binding site on FlhG, their binding depends on the ATP-dependent dimerization state of FlhG. FliM interacts with FlhG independent of nucleotide binding, while FlrA exclusively interacts with the ATP-dependent FlhG dimer and stimulates FlhG ATPase activity. Our in vivo analysis of FlhG partner switching between FliM and FlrA reveals its mechanism in the numerical restriction of flagella, in which the transcriptional activity of FlrA is down-regulated through a negative feedback loop. Our study demonstrates another level of regulatory complexity underlying the spationumerical regulation of flagellar biogenesis and implies that flagellar assembly transcriptionally regulates the production of more initial building blocks.
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17
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Terashima H, Hirano K, Inoue Y, Tokano T, Kawamoto A, Kato T, Yamaguchi E, Namba K, Uchihashi T, Kojima S, Homma M. Assembly mechanism of a supramolecular MS-ring complex to initiate bacterial flagellar biogenesis in Vibrio species. J Bacteriol 2020; 202:JB.00236-20. [PMID: 32482724 PMCID: PMC8404704 DOI: 10.1128/jb.00236-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 05/28/2020] [Indexed: 12/22/2022] Open
Abstract
The bacterial flagellum is an organelle responsible for motility and has a rotary motor comprising the rotor and the stator. Flagellar biogenesis is initiated by the assembly of the MS-ring, a supramolecular complex embedded in the cytoplasmic membrane. The MS-ring consists of a few dozen copies of the transmembrane FliF protein, and is an essential core structure which is a part of the rotor. The number and location of the flagella are controlled by the FlhF and FlhG proteins in some species. However, there is no clarity on the factors initiating MS-ring assembly, and contribution of FlhF/FlhG to this process. Here, we show that FlhF and a C-ring component FliG facilitate Vibrio MS-ring formation. When Vibrio FliF alone was expressed in Escherichia coli cells, MS-ring formation rarely occurred, indicating the requirement of other factors for MS-ring assembly. Consequently, we investigated if FlhF aided FliF in MS-ring assembly. We found that FlhF allowed GFP-fused FliF to localize at the cell pole in a Vibrio cell, suggesting that it increases local concentration of FliF at the pole. When FliF was co-expressed with FlhF in E. coli cells, the MS-ring was effectively formed, indicating that FlhF somehow contributes to MS-ring formation. The isolated MS-ring structure was similar to the MS-ring formed by Salmonella FliF. Interestingly, FliG facilitates MS-ring formation, suggesting that FliF and FliG assist in each other's assembly into the MS-ring and C-ring. This study aids in understanding the mechanism behind MS-ring assembly using appropriate spatial/temporal regulations.Importance Flagellar formation is initiated by the assembly of the FliF protein into the MS-ring complex, embedded in the cytoplasmic membrane. The appropriate spatial/temporal control of MS-ring formation is important for the morphogenesis of the bacterial flagellum. Here, we focus on the assembly mechanism of Vibrio FliF into the MS-ring. FlhF, a positive regulator of the number and location of flagella, recruits the FliF molecules at the cell pole and facilitates MS-ring formation. FliG also facilitates MS-ring formation. Our study showed that these factors control flagellar biogenesis in Vibrio, by initiating the MS-ring assembly. Furthermore, it also implies that flagellar biogenesis is a sophisticated system linked with the expression of certain genes, protein localization and a supramolecular complex assembly.
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Affiliation(s)
- Hiroyuki Terashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Keiichi Hirano
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Yuna Inoue
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takaya Tokano
- Division of Material Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Akihiro Kawamoto
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takayuki Kato
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Erika Yamaguchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- RIKEN Spring-8 Center and Center for Biosystems Dynamic Research, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takayuki Uchihashi
- Division of Material Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi 444-8787, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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18
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Mazzantini D, Fonnesu R, Celandroni F, Calvigioni M, Vecchione A, Mrusek D, Bange G, Ghelardi E. GTP-Dependent FlhF Homodimer Supports Secretion of a Hemolysin in Bacillus cereus. Front Microbiol 2020; 11:879. [PMID: 32435240 PMCID: PMC7218170 DOI: 10.3389/fmicb.2020.00879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/15/2020] [Indexed: 01/09/2023] Open
Abstract
The multidomain (B-NG) protein FlhF, a flagellar biogenesis regulator in several bacteria, is the third paralog of the signal recognition particle (SRP)-GTPases Ffh and FtsY, which are known to drive protein-delivery to the plasma membrane. Previously, we showed that FlhF is required for Bacillus cereus pathogenicity in an insect model of infection, being essential for physiological peritrichous flagellation, for motility, and for the secretion of virulence proteins. Among these proteins, we found that the L2 component of hemolysin BL, one of the most powerful toxins B. cereus produces, was drastically reduced by the FlhF depletion. Herein, we demonstrate that B. cereus FlhF forms GTP-dependent homodimers in vivo since the replacement of residues critical for their GTP-dependent homodimerization alters this ability. The protein directly or indirectly controls flagellation by affecting flagellin-gene transcription and its overproduction leads to a hyperflagellated phenotype. On the other hand, FlhF does not affect the expression of the L2-encoding gene (hblC), but physically binds L2 when in its homodimeric form, recruiting the protein to the plasma membrane for secretion. We additionally show that FlhF overproduction increases L2 secretion and that the FlhF/L2 interaction requires the NG domain of FlhF. Our findings demonstrate the peculiar behavior of B. cereus FlhF, which is required for the correct flagellar pattern and acts as SRP-GTPase in the secretion of a bacterial toxin subunit.
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Affiliation(s)
- Diletta Mazzantini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Rossella Fonnesu
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Francesco Celandroni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Marco Calvigioni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Alessandra Vecchione
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Devid Mrusek
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps University, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps University, Marburg, Germany
| | - Emilia Ghelardi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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19
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Regulation of the Single Polar Flagellar Biogenesis. Biomolecules 2020; 10:biom10040533. [PMID: 32244780 PMCID: PMC7226244 DOI: 10.3390/biom10040533] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 03/30/2020] [Accepted: 03/30/2020] [Indexed: 02/07/2023] Open
Abstract
Some bacterial species, such as the marine bacterium Vibrio alginolyticus, have a single polar flagellum that allows it to swim in liquid environments. Two regulators, FlhF and FlhG, function antagonistically to generate only one flagellum at the cell pole. FlhF, a signal recognition particle (SRP)-type guanosine triphosphate (GTP)ase, works as a positive regulator for flagellar biogenesis and determines the location of flagellar assembly at the pole, whereas FlhG, a MinD-type ATPase, works as a negative regulator that inhibits flagellar formation. FlhF intrinsically localizes at the cell pole, and guanosine triphosphate (GTP) binding to FlhF is critical for its polar localization and flagellation. FlhG also localizes at the cell pole via the polar landmark protein HubP to directly inhibit FlhF function at the cell pole, and this localization depends on ATP binding to FlhG. However, the detailed regulatory mechanisms involved, played by FlhF and FlhG as the major factors, remain largely unknown. This article reviews recent studies that highlight the post-translational regulation mechanism that allows the synthesis of only a single flagellum at the cell pole.
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20
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A Polar Flagellar Transcriptional Program Mediated by Diverse Two-Component Signal Transduction Systems and Basal Flagellar Proteins Is Broadly Conserved in Polar Flagellates. mBio 2020; 11:mBio.03107-19. [PMID: 32127455 PMCID: PMC7064773 DOI: 10.1128/mbio.03107-19] [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] [Indexed: 11/24/2022] Open
Abstract
Relative to peritrichous bacteria, polar flagellates possess regulatory systems that order flagellar gene transcription differently and produce flagella in specific numbers only at poles. How transcriptional and flagellar biogenesis regulatory systems are interlinked to promote the correct synthesis of polar flagella in diverse species has largely been unexplored. We found evidence for many Gram-negative polar flagellates encoding two-component signal transduction systems with activity linked to the formation of flagellar type III secretion systems to enable production of flagellar rod and hook proteins at a discrete, subsequent stage during flagellar assembly. This polar flagellar transcriptional program assists, in some manner, the FlhF/FlhG flagellar biogenesis regulatory system, which forms specific flagellation patterns in polar flagellates in maintaining flagellation and motility when activity of FlhF or FlhG might be altered. Our work provides insight into the multiple regulatory processes required for polar flagellation. Bacterial flagella are rotating nanomachines required for motility. Flagellar gene expression and protein secretion are coordinated for efficient flagellar biogenesis. Polar flagellates, unlike peritrichous bacteria, commonly order flagellar rod and hook gene transcription as a separate step after production of the MS ring, C ring, and flagellar type III secretion system (fT3SS) core proteins that form a competent fT3SS. Conserved regulatory mechanisms in diverse polar flagellates to create this polar flagellar transcriptional program have not been thoroughly assimilated. Using in silico and genetic analyses and our previous findings in Campylobacter jejuni as a foundation, we observed a large subset of Gram-negative bacteria with the FlhF/FlhG regulatory system for polar flagellation to possess flagellum-associated two-component signal transduction systems (TCSs). We present data supporting a general theme in polar flagellates whereby MS ring, rotor, and fT3SS proteins contribute to a regulatory checkpoint during polar flagellar biogenesis. We demonstrate that Vibrio cholerae and Pseudomonas aeruginosa require the formation of this regulatory checkpoint for the TCSs to directly activate subsequent rod and hook gene transcription, which are hallmarks of the polar flagellar transcriptional program. By reprogramming transcription in V. cholerae to more closely follow the peritrichous flagellar transcriptional program, we discovered a link between the polar flagellar transcription program and the activity of FlhF/FlhG flagellar biogenesis regulators in which the transcriptional program allows polar flagellates to continue to produce flagella for motility when FlhF or FlhG activity may be altered. Our findings integrate flagellar transcriptional and biogenesis regulatory processes involved in polar flagellation in many species.
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21
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Zhang K, He J, Cantalano C, Guo Y, Liu J, Li C. FlhF regulates the number and configuration of periplasmic flagella in Borrelia burgdorferi. Mol Microbiol 2020; 113:1122-1139. [PMID: 32039533 DOI: 10.1111/mmi.14482] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 12/17/2022]
Abstract
The Lyme disease bacterium Borrelia burgdorferi has 7-11 periplasmic flagella (PF) that arise from the cell poles and extend toward the midcell as a flat-ribbon, which is distinct from other bacteria. FlhF, a signal recognition particle (SRP)-like GTPase, has been found to regulate the flagellar number and polarity; however, its role in B. burgdorferi remains unknown. B. burgdorferi has an FlhF homolog (BB0270). Structural and biochemical analyses show that BB0270 has a similar structure and enzymatic activity as its counterparts from other bacteria. Genetics and cryo-electron tomography studies reveal that deletion of BB0270 leads to mutant cells that have less PF (4 ± 2 PF per cell tip) and fail to form a flat-ribbon, indicative of a role of BB0270 in the control of PF number and configuration. Mechanistically, we demonstrate that BB0270 localizes at the cell poles and controls the number and position of PF via regulating the flagellar protein stability and the polar localization of the MS-ring protein FliF. Our study not only provides the detailed characterizations of BB0270 and its profound impacts on flagellar assembly, morphology and motility in B. burgdorferi, but also unveils mechanistic insights into how spirochetes control their unique flagellar patterns.
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Affiliation(s)
- Kai Zhang
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA
| | - Jun He
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Claudio Cantalano
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA.,Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - Youzhong Guo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA.,Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Chunhao Li
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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22
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Henderson LD, Matthews-Palmer TRS, Gulbronson CJ, Ribardo DA, Beeby M, Hendrixson DR. Diversification of Campylobacter jejuni Flagellar C-Ring Composition Impacts Its Structure and Function in Motility, Flagellar Assembly, and Cellular Processes. mBio 2020; 11:e02286-19. [PMID: 31911488 PMCID: PMC6946799 DOI: 10.1128/mbio.02286-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/19/2019] [Indexed: 12/22/2022] Open
Abstract
Bacterial flagella are reversible rotary motors that rotate external filaments for bacterial propulsion. Some flagellar motors have diversified by recruiting additional components that influence torque and rotation, but little is known about the possible diversification and evolution of core motor components. The mechanistic core of flagella is the cytoplasmic C ring, which functions as a rotor, directional switch, and assembly platform for the flagellar type III secretion system (fT3SS) ATPase. The C ring is composed of a ring of FliG proteins and a helical ring of surface presentation of antigen (SPOA) domains from the switch proteins FliM and one of two usually mutually exclusive paralogs, FliN or FliY. We investigated the composition, architecture, and function of the C ring of Campylobacter jejuni, which encodes FliG, FliM, and both FliY and FliN by a variety of interrogative approaches. We discovered a diversified C. jejuni C ring containing FliG, FliM, and both FliY, which functions as a classical FliN-like protein for flagellar assembly, and FliN, which has neofunctionalized into a structural role. Specific protein interactions drive the formation of a more complex heterooligomeric C. jejuni C-ring structure. We discovered that this complex C ring has additional cellular functions in polarly localizing FlhG for numerical regulation of flagellar biogenesis and spatial regulation of division. Furthermore, mutation of the C. jejuni C ring revealed a T3SS that was less dependent on its ATPase complex for assembly than were other systems. Our results highlight considerable evolved flagellar diversity that impacts motor output, biogenesis, and cellular processes in different species.IMPORTANCE The conserved core of bacterial flagellar motors reflects a shared evolutionary history that preserves the mechanisms essential for flagellar assembly, rotation, and directional switching. In this work, we describe an expanded and diversified set of core components in the Campylobacter jejuni flagellar C ring, the mechanistic core of the motor. Our work provides insight into how usually conserved core components may have diversified by gene duplication, enabling a division of labor of the ancestral protein between the two new proteins, acquisition of new roles in flagellar assembly and motility, and expansion of the function of the flagellum beyond motility, including spatial regulation of cell division and numerical control of flagellar biogenesis in C. jejuni Our results highlight that relatively small changes, such as gene duplications, can have substantial ramifications on the cellular roles of a molecular machine.
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Affiliation(s)
- Louie D Henderson
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Connor J Gulbronson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Deborah A Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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23
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Ramm B, Heermann T, Schwille P. The E. coli MinCDE system in the regulation of protein patterns and gradients. Cell Mol Life Sci 2019; 76:4245-4273. [PMID: 31317204 PMCID: PMC6803595 DOI: 10.1007/s00018-019-03218-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/27/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022]
Abstract
Molecular self-organziation, also regarded as pattern formation, is crucial for the correct distribution of cellular content. The processes leading to spatiotemporal patterns often involve a multitude of molecules interacting in complex networks, so that only very few cellular pattern-forming systems can be regarded as well understood. Due to its compositional simplicity, the Escherichia coli MinCDE system has, thus, become a paradigm for protein pattern formation. This biological reaction diffusion system spatiotemporally positions the division machinery in E. coli and is closely related to ParA-type ATPases involved in most aspects of spatiotemporal organization in bacteria. The ATPase MinD and the ATPase-activating protein MinE self-organize on the membrane as a reaction matrix. In vivo, these two proteins typically oscillate from pole-to-pole, while in vitro they can form a variety of distinct patterns. MinC is a passenger protein supposedly operating as a downstream cue of the system, coupling it to the division machinery. The MinCDE system has helped to extract not only the principles underlying intracellular patterns, but also how they are shaped by cellular boundaries. Moreover, it serves as a model to investigate how patterns can confer information through specific and non-specific interactions with other molecules. Here, we review how the three Min proteins self-organize to form patterns, their response to geometric boundaries, and how these patterns can in turn induce patterns of other molecules, focusing primarily on experimental approaches and developments.
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Affiliation(s)
- Beatrice Ramm
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Tamara Heermann
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
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24
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Steinberg R, Knüpffer L, Origi A, Asti R, Koch HG. Co-translational protein targeting in bacteria. FEMS Microbiol Lett 2019; 365:4966980. [PMID: 29790984 DOI: 10.1093/femsle/fny095] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/09/2018] [Indexed: 01/16/2023] Open
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and have to be transported into or across the cytoplasmic membrane. Bacteria use multiple protein transport systems in parallel, but the majority of proteins engage two distinct targeting systems. One is the co-translational targeting by two universally conserved GTPases, the signal recognition particle (SRP) and its receptor FtsY, which deliver inner membrane proteins to either the SecYEG translocon or the YidC insertase for membrane insertion. The other targeting system depends on the ATPase SecA, which targets secretory proteins, i.e. periplasmic and outer membrane proteins, to SecYEG for their subsequent ATP-dependent translocation. While SRP selects its substrates already very early during their synthesis, the recognition of secretory proteins by SecA is believed to occur primarily after translation termination, i.e. post-translationally. In this review we highlight recent progress on how SRP recognizes its substrates at the ribosome and how the fidelity of the targeting reaction to SecYEG is maintained. We furthermore discuss similarities and differences in the SRP-dependent targeting to either SecYEG or YidC and summarize recent results that suggest that some membrane proteins are co-translationally targeted by SecA.
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Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Lara Knüpffer
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, Freiburg D-79104, Germany
| | - Rossella Asti
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
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25
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Wild K, Becker MM, Kempf G, Sinning I. Structure, dynamics and interactions of large SRP variants. Biol Chem 2019; 401:63-80. [DOI: 10.1515/hsz-2019-0282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/09/2019] [Indexed: 12/11/2022]
Abstract
Abstract
Co-translational protein targeting to membranes relies on the signal recognition particle (SRP) system consisting of a cytosolic ribonucleoprotein complex and its membrane-associated receptor. SRP recognizes N-terminal cleavable signals or signal anchor sequences, retards translation, and delivers ribosome-nascent chain complexes (RNCs) to vacant translocation channels in the target membrane. While our mechanistic understanding is well advanced for the small bacterial systems it lags behind for the large bacterial, archaeal and eukaryotic SRP variants including an Alu and an S domain. Here we describe recent advances on structural and functional insights in domain architecture, particle dynamics and interplay with RNCs and translocon and GTP-dependent regulation of co-translational protein targeting stimulated by SRP RNA.
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Affiliation(s)
- Klemens Wild
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Matthias M.M. Becker
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Georg Kempf
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH) , INF 328 , D-69120 Heidelberg , Germany
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26
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Navarrete B, Leal-Morales A, Serrano-Ron L, Sarrió M, Jiménez-Fernández A, Jiménez-Díaz L, López-Sánchez A, Govantes F. Transcriptional organization, regulation and functional analysis of flhF and fleN in Pseudomonas putida. PLoS One 2019; 14:e0214166. [PMID: 30889223 PMCID: PMC6424431 DOI: 10.1371/journal.pone.0214166] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/07/2019] [Indexed: 11/25/2022] Open
Abstract
The Pseudomonas putida flhA-flhF-fleN-fliA cluster encodes a component of the flagellar export gate and three regulatory elements potentially involved in flagellar biogenesis and other functions. Here we show that these four genes form an operon, whose transcription is driven from the upstream PflhA promoter. A second promoter, PflhF, provides additional transcription of the three distal genes. PflhA and PflhF are σN-dependent, activated by the flagellar regulator FleQ, and negatively regulated by FleN. Motility, surface adhesion and colonization defects of a transposon insertion mutant in flhF revealed transcriptional polarity on fleN and fliA, as the former was required for strong surface adhesion and biofilm formation, and the latter was required for flagellar synthesis. On the other hand, FlhF and FleN were necessary to attain proper flagellar location and number for a fully functional flagellar complement. FleN, along with FleQ and the second messenger c-di-GMP differentially regulated transcription of lapA and the bcs operon, encoding a large adhesion protein and cellulose synthase. FleQ positively regulated the PlapA promoter and activation was antagonized by FleN and c-di-GMP. PbcsD was negatively regulated by FleQ and FleN, and repression was antagonized by c-di-GMP. FleN promoted FleQ binding to both PlapA and PbcsD in vitro, while c-di-GMP antagonized interaction with PbcsD and stimulated interaction with PlapA. A single FleQ binding site in PlapA was critical to activation in vivo. Our results suggest that FleQ, FleN and c-di-GMP cooperate to coordinate the regulation of flagellar motility and biofilm development.
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Affiliation(s)
- Blanca Navarrete
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Antonio Leal-Morales
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Laura Serrano-Ron
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Marina Sarrió
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Alicia Jiménez-Fernández
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Lorena Jiménez-Díaz
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Aroa López-Sánchez
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
| | - Fernando Govantes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Sevilla, Spain
- Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, Sevilla, Spain
- * E-mail:
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27
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Kempf G, Stjepanovic G, Sloan J, Hendricks A, Lapouge K, Sinning I. The Escherichia coli SRP Receptor Forms a Homodimer at the Membrane. Structure 2018; 26:1440-1450.e5. [PMID: 30146170 DOI: 10.1016/j.str.2018.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 06/14/2018] [Accepted: 07/22/2018] [Indexed: 01/19/2023]
Abstract
The Escherichia coli signal recognition particle (SRP) receptor, FtsY, plays a fundamental role in co-translational targeting of membrane proteins via the SRP pathway. Efficient targeting relies on membrane interaction of FtsY and heterodimerization with the SRP protein Ffh, which is driven by detachment of α helix (αN1) in FtsY. Here we show that apart from the heterodimer, FtsY forms a nucleotide-dependent homodimer on the membrane, and upon αN1 removal also in solution. Homodimerization triggers reciprocal stimulation of GTP hydrolysis and occurs in vivo. Biochemical characterization together with integrative modeling suggests that the homodimer employs the same interface as the heterodimer. Structure determination of FtsY NG+1 with GMPPNP shows that a dimerization-induced conformational switch of the γ-phosphate is conserved in Escherichia coli, filling an important gap in SRP GTPase activation. Our findings add to the current understanding of SRP GTPases and may challenge previous studies that did not consider homodimerization of FtsY.
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Affiliation(s)
- Georg Kempf
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany
| | - Goran Stjepanovic
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany
| | - Jeremy Sloan
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany
| | - Astrid Hendricks
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany
| | - Karine Lapouge
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Centre, Heidelberg 69120, Germany.
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28
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Kondo S, Imura Y, Mizuno A, Homma M, Kojima S. Biochemical analysis of GTPase FlhF which controls the number and position of flagellar formation in marine Vibrio. Sci Rep 2018; 8:12115. [PMID: 30108243 PMCID: PMC6092412 DOI: 10.1038/s41598-018-30531-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 08/01/2018] [Indexed: 11/18/2022] Open
Abstract
FlhF controls the number and position of the polar flagellar formation of Vibrio species. FlhF, is a paralog of FtsY, a GTPase acting in the Sec membrane transport system of bacteria, and localizes at the cell pole. Mutations in the conserved GTPase motif of FlhF lost polar localization capability and flagellar formation. Vibrio FlhF has not, until now, been purified as soluble protein. Here, we report that addition of MgCl2 and GTP or GDP at the step of cell lysis greatly improved the solubility of FlhF, allowing us to purify it in homogeneity. Purified FlhF showed GTPase activity only in the presence of FlhG. Of twelve FlhF GTPase motif mutants showing reduced function, eleven were recovered as precipitate after the cell disruption. The E440K substitution could be purified and showed no GTPase activity even in the presence of FlhG. Interestingly an FlhF substitution in the putative catalytic residue for GTP hydrolysis, R334A, allowed normal flagellar formation although GTPase activity of FlhF was completely abolished. Furthermore, size exclusion chromatography of purified FlhF revealed that it forms dimers in the presence of GTP but exists as monomer in the presence of GDP. We speculate that the GTP binding allows FlhF to dimerize and localize at the pole where it initiates flagellar formation, and the GDP-bound form diffuses as monomer.
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Affiliation(s)
- Shota Kondo
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Yoshino Imura
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Akira Mizuno
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
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29
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Kondo S, Homma M, Kojima S. Analysis of the GTPase motif of FlhF in the control of the number and location of polar flagella in Vibrio alginolyticus. Biophys Physicobiol 2017; 14:173-181. [PMID: 29362702 PMCID: PMC5774409 DOI: 10.2142/biophysico.14.0_173] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 11/07/2017] [Indexed: 12/21/2022] Open
Abstract
Vibrio alginolyticus normally has a single polar flagellum whose number and placement are regulated positively by FlhF. FlhF is a GTPase and homolog of a signal recognition particle (SRP) protein called Ffh and SRP receptor FtsY. FlhF is located at the cell pole and directs formation of the flagellum. To study the mechanism of FlhF localization, we introduced random mutations into flhF by means of hydroxylamine and isolated mutants that could not generate the flagellum at the cell pole. The novel mutations were only mapped to the GTPase motif of FlhF. The mutant FlhF proteins showed reduced polar localization as compared to the wild type and still could associate with the membrane. These results support the assumption that the GTPase motif of FlhF plays a critical role in the polar localization of this protein during formation of the flagellum.
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Affiliation(s)
- Shota Kondo
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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30
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Inaba S, Nishigaki T, Takekawa N, Kojima S, Homma M. Localization and domain characterization of the SflA regulator of flagellar formation in Vibrio alginolyticus. Genes Cells 2017; 22:619-627. [DOI: 10.1111/gtc.12501] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/07/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Satoshi Inaba
- Division of Biological Science, Graduate School of Science; Nagoya University; Chikusa-Ku Nagoya 464-8602 Japan
| | - Takehiko Nishigaki
- Division of Biological Science, Graduate School of Science; Nagoya University; Chikusa-Ku Nagoya 464-8602 Japan
| | - Norihiro Takekawa
- Division of Biological Science, Graduate School of Science; Nagoya University; Chikusa-Ku Nagoya 464-8602 Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science; Nagoya University; Chikusa-Ku Nagoya 464-8602 Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science; Nagoya University; Chikusa-Ku Nagoya 464-8602 Japan
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31
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Becker MMM, Lapouge K, Segnitz B, Wild K, Sinning I. Structures of human SRP72 complexes provide insights into SRP RNA remodeling and ribosome interaction. Nucleic Acids Res 2016; 45:470-481. [PMID: 27899666 PMCID: PMC5224484 DOI: 10.1093/nar/gkw1124] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/21/2016] [Accepted: 10/28/2016] [Indexed: 12/30/2022] Open
Abstract
Co-translational protein targeting and membrane protein insertion is a fundamental process and depends on the signal recognition particle (SRP). In mammals, SRP is composed of the SRP RNA crucial for SRP assembly and function and six proteins. The two largest proteins SRP68 and SRP72 form a heterodimer and bind to a regulatory site of the SRP RNA. Despite their essential roles in the SRP pathway, structural information has been available only for the SRP68 RNA-binding domain (RBD). Here we present the crystal structures of the SRP68 protein-binding domain (PBD) in complex with SRP72-PBD and of the SRP72-RBD bound to the SRP S domain (SRP RNA, SRP19 and SRP68) detailing all interactions of SRP72 within SRP. The SRP72-PBD is a tetratricopeptide repeat, which binds an extended linear motif of SRP68 with high affinity. The SRP72-RBD is a flexible peptide crawling along the 5e- and 5f-loops of SRP RNA. A conserved tryptophan inserts into the 5e-loop forming a novel type of RNA kink-turn stabilized by a potassium ion, which we define as K+-turn. In addition, SRP72-RBD remodels the 5f-loop involved in ribosome binding and visualizes SRP RNA plasticity. Docking of the S domain structure into cryo-electron microscopy density maps reveals multiple contact sites between SRP68/72 and the ribosome, and explains the role of SRP72 in the SRP pathway.
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Affiliation(s)
- Matthias M M Becker
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Karine Lapouge
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Bernd Segnitz
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
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32
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HubP, a Polar Landmark Protein, Regulates Flagellar Number by Assisting in the Proper Polar Localization of FlhG in Vibrio alginolyticus. J Bacteriol 2016; 198:3091-3098. [PMID: 27573015 DOI: 10.1128/jb.00462-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/22/2016] [Indexed: 01/06/2023] Open
Abstract
The marine bacterium Vibrio alginolyticus has a single polar flagellum, the number of which is regulated positively by FlhF and negatively by FlhG. FlhF is intrinsically localized at the cell pole, whereas FlhG is localized there through putative interactions with the polar landmark protein HubP. Here we focused on the role of HubP in the regulation of flagellar number in V. alginolyticus Deletion of hubP increased the flagellar number and completely disrupted the polar localization of FlhG. It was thought that the flagellar number is determined primarily by the absolute amount of FlhF localized at the cell pole. Here we found that deletion of hubP increased the flagellar number although it did not increase the polar amount of FlhF. We also found that FlhG overproduction did not reduce the polar localization of FlhF. These results show that the absolute amount of FlhF is not always the determinant of flagellar number. We speculate that cytoplasmic FlhG works as a quantitative regulator, controlling the amount of FlhF localized at the pole, and HubP-anchored polar FlhG works as a qualitative regulator, directly inhibiting the activity of polar FlhF. This regulation by FlhF, FlhG, and HubP might contribute to achieving optimal flagellar biogenesis at the cell pole in V. alginolyticus IMPORTANCE: For regulation of the flagellar number in marine Vibrio, two proteins, FlhF and FlhG, work as positive and negative regulators, respectively. In this study, we found that the polar landmark protein HubP is involved in the regulation of flagellar biogenesis. Deletion of hubP increased the number of flagella without increasing the amount of pole-localizing FlhF, indicating that the number of flagella is not determined solely by the absolute amount of pole-localizing FlhF, which is inconsistent with the previous model. We propose that cytoplasmic FlhG and HubP-anchored polar FlhG negatively regulate flagellar formation through two independent schemes.
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33
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Kojima S. Studies on the mechanism of bacterial flagellar rotation and the flagellar number regulation. Nihon Saikingaku Zasshi 2016; 71:185-97. [PMID: 27581279 DOI: 10.3412/jsb.71.185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many motile bacteria have the motility organ, the flagellum. It rotates by the rotary motor driven by the ion-motive force and is embedded in the cell surface at the base of each flagellar filament. Many researchers have been studying its rotary mechanism for years, but most of the energy conversion processes have been remained in mystery. We focused on the flagellar stator, which works at the core process of energy conversion, and found that the periplasmic region of the stator changes its conformation to be activated only when the stator units are incorporated into the motor and anchored at the cell wall. Meanwhile, the physiologically important supramolecular complex is localized in the cell at the right place and the right time with a proper amount. How the cell achieves such a proper localization is the fundamental question for life science, and we undertake this problem by analyzing the mechanism for biogenesis of a single polar flagellum of Vibrio alginolyticus. Here I describe the molecular mechanism of how the flagellum is generated at the specific place with a proper number, and also how the flagellar stator is incorporated into the motor to complete the functional motor assembly, based on our studies.
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Affiliation(s)
- Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
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Kumar B, Cardona ST. Synthetic Cystic Fibrosis Sputum Medium Regulates Flagellar Biosynthesis through the flhF Gene in Burkholderia cenocepacia. Front Cell Infect Microbiol 2016; 6:65. [PMID: 27379216 PMCID: PMC4905959 DOI: 10.3389/fcimb.2016.00065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/30/2016] [Indexed: 12/03/2022] Open
Abstract
Burkholderia cenocepacia belongs to the Burkholderia cepacia complex (Bcc), a group of at least 18 distinct species that establish chronic infections in the lung of people with the genetic disease cystic fibrosis (CF). The sputum of CF patients is rich in amino acids and was previously shown to increase flagellar gene expression in B. cenocepacia. We examined flagellin expression and flagellar morphology of B. cenocepacia grown in synthetic cystic fibrosis sputum medium (SCFM) compared to minimal medium. We found that CF nutritional conditions induce increased motility and flagellin expression. Individual amino acids added at the same concentrations as found in SCFM also increased motility but not flagellin expression, suggesting a chemotactic effect of amino acids. Electron microscopy and flagella staining demonstrated that the increase in flagellin corresponds to a change in the number of flagella per cell. In minimal medium, the ratio of multiple: single: aflagellated cells was 2:3.5:4.5; while under SCFM conditions, the ratio was 7:2:1. We created a deletion mutant, ΔflhF, to study whether this putative GTPase regulates the flagellation pattern of B. cenocepacia K56-2 during growth in CF conditions. The ΔflhF mutant exhibited 80% aflagellated, 14% single and 6% multiple flagellated bacterial subpopulations. Moreover, the ratio of multiple to single flagella in WT and ΔflhF was 3.5 and 0.43, respectively in CF conditions. The observed differences suggest that FlhF positively regulates flagellin expression and the flagellation pattern in B. cenocepacia K56-2 during CF nutritional conditions.
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Affiliation(s)
- Brijesh Kumar
- Department of Microbiology, University of Manitoba Winnipeg, MB, Canada
| | - Silvia T Cardona
- Department of Microbiology, University of ManitobaWinnipeg, MB, Canada; Department of Medical Microbiology and Infectious Diseases, University of ManitobaWinnipeg, MB, Canada
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35
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Wild K, Bange G, Motiejunas D, Kribelbauer J, Hendricks A, Segnitz B, Wade RC, Sinning I. Structural Basis for Conserved Regulation and Adaptation of the Signal Recognition Particle Targeting Complex. J Mol Biol 2016; 428:2880-97. [PMID: 27241309 DOI: 10.1016/j.jmb.2016.05.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/13/2016] [Accepted: 05/18/2016] [Indexed: 12/25/2022]
Abstract
The signal recognition particle (SRP) is a ribonucleoprotein complex with a key role in targeting and insertion of membrane proteins. The two SRP GTPases, SRP54 (Ffh in bacteria) and FtsY (SRα in eukaryotes), form the core of the targeting complex (TC) regulating the SRP cycle. The architecture of the TC and its stimulation by RNA has been described for the bacterial SRP system while this information is lacking for other domains of life. Here, we present the crystal structures of the GTPase heterodimers of archaeal (Sulfolobus solfataricus), eukaryotic (Homo sapiens), and chloroplast (Arabidopsis thaliana) SRP systems. The comprehensive structural comparison combined with Brownian dynamics simulations of TC formation allows for the description of the general blueprint and of specific adaptations of the quasi-symmetric heterodimer. Our work defines conserved external nucleotide-binding sites for SRP GTPase activation by RNA. Structural analyses of the GDP-bound, post-hydrolysis states reveal a conserved, magnesium-sensitive switch within the I-box. Overall, we provide a general model for SRP cycle regulation by RNA.
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Affiliation(s)
- Klemens Wild
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
| | - Gert Bange
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
| | - Domantas Motiejunas
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, Germany
| | - Judith Kribelbauer
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
| | - Astrid Hendricks
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
| | - Bernd Segnitz
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany
| | - Rebecca C Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg, Germany; Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, INF 282, 69120 Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), INF 328, D-69120 Heidelberg, Germany.
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36
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Gulbronson CJ, Ribardo DA, Balaban M, Knauer C, Bange G, Hendrixson DR. FlhG employs diverse intrinsic domains and influences FlhF GTPase activity to numerically regulate polar flagellar biogenesis in Campylobacter jejuni. Mol Microbiol 2015; 99:291-306. [PMID: 26411371 DOI: 10.1111/mmi.13231] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2015] [Indexed: 11/30/2022]
Abstract
Flagellation in polar flagellates is one of the rare biosynthetic processes known to be numerically regulated in bacteria. Polar flagellates must spatially and numerically regulate flagellar biogenesis to create flagellation patterns for each species that are ideal for motility. FlhG ATPases numerically regulate polar flagellar biogenesis, yet FlhG orthologs are diverse in motif composition. We discovered that Campylobacter jejuni FlhG is at the center of a multipartite mechanism that likely influences a flagellar biosynthetic step to control flagellar number for amphitrichous flagellation, rather than suppressing activators of flagellar gene transcription as in Vibrio and Pseudomonas species. Unlike other FlhG orthologs, the FlhG ATPase domain was not required to regulate flagellar number in C. jejuni. Instead, two regions of C. jejuni FlhG that are absent or significantly altered in FlhG orthologs are involved in numerical regulation of flagellar biogenesis. Additionally, we found that C. jejuni FlhG influences FlhF GTPase activity, which may mechanistically contribute to flagellar number regulation. Our work suggests that FlhG ATPases divergently evolved in each polarly flagellated species to employ different intrinsic domains and extrinsic effectors to ultimately mediate a common output - precise numerical control of polar flagellar biogenesis required to create species-specific flagellation patterns optimal for motility.
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Affiliation(s)
- Connor J Gulbronson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Deborah A Ribardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Murat Balaban
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Carina Knauer
- LOEWE Center for Synthetic Microbiology (Synmikro) and Department of Chemistry, Philipps University Marburg, 35403, Marburg, Germany
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology (Synmikro) and Department of Chemistry, Philipps University Marburg, 35403, Marburg, Germany
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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Altegoer F, Bange G. Undiscovered regions on the molecular landscape of flagellar assembly. Curr Opin Microbiol 2015; 28:98-105. [PMID: 26490009 DOI: 10.1016/j.mib.2015.08.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/27/2015] [Accepted: 08/28/2015] [Indexed: 01/10/2023]
Abstract
The bacterial flagellum is a motility structure and one of the most complicated motors in the biosphere. A flagellum consists of several dozens of building blocks in different stoichiometries and extends from the cytoplasm to the extracellular space. Flagellar biogenesis follows a strict spatio-temporal regime that is guided by a plethora of flagellar assembly factors and chaperones. The goal of this review is to summarize our current structural and mechanistic knowledge of this intricate process and to identify the undiscovered regions on the molecular landscape of flagellar assembly.
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Affiliation(s)
- Florian Altegoer
- LOEWE Center for Synthetic Microbiology & Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, C7, 35043 Marburg, Germany
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology & Department of Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, C7, 35043 Marburg, Germany.
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38
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Rossmann F, Brenzinger S, Knauer C, Dörrich AK, Bubendorfer S, Ruppert U, Bange G, Thormann KM. The role of FlhF and HubP as polar landmark proteins in Shewanella putrefaciens CN-32. Mol Microbiol 2015; 98:727-42. [PMID: 26235439 DOI: 10.1111/mmi.13152] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2015] [Indexed: 01/06/2023]
Abstract
Spatiotemporal regulation of cell polarity plays a role in many fundamental processes in bacteria and often relies on 'landmark' proteins which recruit the corresponding clients to their designated position. Here, we explored the localization of two multi-protein complexes, the polar flagellar motor and the chemotaxis array, in Shewanella putrefaciens CN-32. We demonstrate that polar positioning of the flagellar system, but not of the chemotaxis system, depends on the GTPase FlhF. In contrast, the chemotaxis array is recruited by a transmembrane protein which we identified as the functional ortholog of Vibrio cholerae HubP. Mediated by its periplasmic N-terminal LysM domain, SpHubP exhibits an FlhF-independent localization pattern during cell cycle similar to its Vibrio counterpart and also has a role in proper chromosome segregation. In addition, while not affecting flagellar positioning, SpHubP is crucial for normal flagellar function and is involved in type IV pili-mediated twitching motility. We hypothesize that a group of HubP/FimV homologs, characterized by a rather conserved N-terminal periplasmic section required for polar targeting and a highly variable acidic cytoplasmic part, primarily mediating recruitment of client proteins, serves as polar markers in various bacterial species with respect to different cellular functions.
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Affiliation(s)
- Florian Rossmann
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany.,Department of Ecophysiology, Max-Planck-Institut für terrestrische Mikrobiologie, 35043, Marburg, Germany
| | - Susanne Brenzinger
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany.,Department of Ecophysiology, Max-Planck-Institut für terrestrische Mikrobiologie, 35043, Marburg, Germany
| | - Carina Knauer
- LOEWE Center for Synthetic Microbiology (Synmikro) & Department of Chemistry, Philipps University Marburg, 35043, Marburg, Germany
| | - Anja K Dörrich
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany
| | - Sebastian Bubendorfer
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany
| | - Ulrike Ruppert
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology (Synmikro) & Department of Chemistry, Philipps University Marburg, 35043, Marburg, Germany
| | - Kai M Thormann
- Department of Microbiology and Molecular Biology, Justus-Liebig Universität, 35392, Giessen, Germany
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39
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Gao T, Shi M, Ju L, Gao H. Investigation into FlhFG reveals distinct features of FlhF in regulating flagellum polarity in Shewanella oneidensis. Mol Microbiol 2015; 98:571-85. [PMID: 26194016 DOI: 10.1111/mmi.13141] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 12/14/2022]
Abstract
Rod-shaped bacterial cells are polarized, with many organelles confined to a polar cellular site. In polar flagellates, FlhF and FlhG, a multiple-domain (B-N-G) GTPase and a MinD-like ATPase respectively, function as a cognate pair to regulate flagellar localization and number as revealed in Vibrio and Pseudomonas species. In this study, we show that FlhFG of Shewanella oneidensis (SoFlhFG), a monotrichous γ-proteobacterium renowned for respiratory diversity, also play an important role in the flagellar polar placement and number control. Despite this, SoFlhFG exhibit distinct features that are not observed in the characterized counterparts. Most strikingly, the G domain of SoFlhF determines the polar placement, contrasting the N domain of the Vibrio cholerae FlhF. The SoFlhF N domain in fact counteracts the function of the G domain with respect to the terminal targeting in the absence of the B domain. We further show that GTPase activity of SoFlhF is essential for motility but not positioning. Overall, our results suggest that mechanisms underlying the polar placement of organelles appear to be diverse, even for evolutionally relatively conserved flagellum.
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Affiliation(s)
- Tong Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Miaomiao Shi
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Lili Ju
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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40
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Schuhmacher JS, Thormann KM, Bange G. How bacteria maintain location and number of flagella? FEMS Microbiol Rev 2015. [PMID: 26195616 DOI: 10.1093/femsre/fuv034] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacteria differ in number and location of their flagella that appear in regular patterns at the cell surface (flagellation pattern). Despite the plethora of bacterial species, only a handful of these patterns exist. The correct flagellation pattern is a prerequisite for motility, but also relates to biofilm formation and the pathogenicity of disease-causing flagellated bacteria. However, the mechanisms that maintain location and number of flagella are far from being understood. Here, we review our knowledge on mechanisms that enable bacteria to maintain their appropriate flagellation pattern. While some peritrichous flagellation patterns might occur by rather simple stochastic processes, other bacterial species appear to rely on landmark systems to define the designated flagellar position. Such landmarks are the Tip system of Caulobacter crescentus or the signal recognition particle (SRP)-GTPase FlhF and the MinD/ParA-type ATPase FlhG (synonyms: FleN, YlxH and MinD2). The latter two proteins constitute a regulatory circuit essential for diverse flagellation patterns in many Gram-positive and negative species. The interactome of FlhF/G (e.g. C-ring proteins FliM, FliN, FliY or the transcriptional regulator FleQ/FlrA) seems evolutionary adapted to meet the specific needs for a respective pattern. This variability highlights the importance of the correct flagellation pattern for motile species.
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Affiliation(s)
- Jan S Schuhmacher
- LOEWE Center for Synthetic Microbiology & Dep. of Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35043 Marburg, Germany
| | - Kai M Thormann
- Justus-Liebig University, Department of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| | - Gert Bange
- LOEWE Center for Synthetic Microbiology & Dep. of Chemistry, Philipps University Marburg, Hans-Meerwein-Strasse, D-35043 Marburg, Germany
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41
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Ono H, Takashima A, Hirata H, Homma M, Kojima S. The MinD homolog FlhG regulates the synthesis of the single polar flagellum of Vibrio alginolyticus. Mol Microbiol 2015; 98:130-41. [PMID: 26112286 DOI: 10.1111/mmi.13109] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2015] [Indexed: 01/09/2023]
Abstract
FlhG, a MinD homolog and an ATPase, is known to mediate the formation of the single polar flagellum of Vibrio alginolyticus together with FlhF. FlhG and FlhF work antagonistically, with FlhF promoting flagellar assembly and FlhG inhibiting it. Here, we demonstrate that purified FlhG exhibits a low basal ATPase activity. As with MinD, the basal ATPase activity of FlhG can be activated and the D171A residue substitution enhances its ATPase activity sevenfold. FlhG-D171A localizes strongly at the cell pole and severely inhibits motility and flagellation, whereas the FlhG K31A and K36Q mutants, which are defective in ATP binding, do not localize to the poles, cannot complement a flhG mutant and lead to hyperflagellation. A strong polar localization of FlhF is observed with the K36Q mutant FlhG but not with the wild-type or D171A mutant FlhG. Unexpectedly, an Ala substitution at the catalytic residue (D60A), which abolishes ATPase activity but still allows ATP binding, only slightly affects FlhG functions. These results suggest that the ATP-dependent polar localization of FlhG is crucial for its ability to downregulate the number of polar flagella. We speculate that ATP hydrolysis by FlhG is required for the fine tuning of the regulation.
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Affiliation(s)
- Hiroki Ono
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya, 464-8602, Japan
| | - Akari Takashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya, 464-8602, Japan
| | - Hikaru Hirata
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya, 464-8602, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya, 464-8602, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya, 464-8602, Japan
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42
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MinD-like ATPase FlhG effects location and number of bacterial flagella during C-ring assembly. Proc Natl Acad Sci U S A 2015; 112:3092-7. [PMID: 25733861 DOI: 10.1073/pnas.1419388112] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The number and location of flagella, bacterial organelles of locomotion, are species specific and appear in regular patterns that represent one of the earliest taxonomic criteria in microbiology. However, the mechanisms that reproducibly establish these patterns during each round of cell division are poorly understood. FlhG (previously YlxH) is a major determinant for a variety of flagellation patterns. Here, we show that FlhG is a structural homolog of the ATPase MinD, which serves in cell-division site determination. Like MinD, FlhG forms homodimers that are dependent on ATP and lipids. It interacts with a complex of the flagellar C-ring proteins FliM and FliY (also FliN) in the Gram-positive, peritrichous-flagellated Bacillus subtilis and the Gram-negative, polar-flagellated Shewanella putrefaciens. FlhG interacts with FliM/FliY in a nucleotide-independent manner and activates FliM/FliY to assemble with the C-ring protein FliG in vitro. FlhG-driven assembly of the FliM/FliY/FliG complex is strongly enhanced by ATP and lipids. The protein shows a highly dynamic subcellular distribution between cytoplasm and flagellar basal bodies, suggesting that FlhG effects flagellar location and number during assembly of the C-ring. We describe the molecular evolution of a MinD-like ATPase into a flagellation pattern effector and suggest that the underappreciated structural diversity of the C-ring proteins might contribute to the formation of different flagellation patterns.
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Abstract
Bacterial flagellar motility is among the most extensively studied physiological systems in biology, but most research has been restricted to using the highly similar Gram-negative species Escherichia coli and Salmonella enterica. Here, we review the recent advances in the study of flagellar structure and regulation of the distantly related and genetically tractable Gram-positive bacterium Bacillus subtilis. B. subtilis has a thicker layer of peptidoglycan and lacks the outer membrane of the Gram-negative bacteria; thus, not only phylogenetic separation but also differences in fundamental cell architecture contribute to deviations in flagellar structure and regulation. We speculate that a large number of flagella and the absence of a periplasm make B. subtilis a premier organism for the study of the earliest events in flagellar morphogenesis and the type III secretion system. Furthermore, B. subtilis has been instrumental in the study of heterogeneous gene transcription in subpopulations and of flagellar regulation at the translational and functional level.
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Abstract
Accurate folding, assembly, localization, and maturation of newly synthesized proteins are essential to all cells and require high fidelity in the protein biogenesis machineries that mediate these processes. Here, we review our current understanding of how high fidelity is achieved in one of these processes, the cotranslational targeting of nascent membrane and secretory proteins by the signal recognition particle (SRP). Recent biochemical, biophysical, and structural studies have elucidated how the correct substrates drive a series of elaborate conformational rearrangements in the SRP and SRP receptor GTPases; these rearrangements provide effective fidelity checkpoints to reject incorrect substrates and enhance the fidelity of this essential cellular pathway. The mechanisms used by SRP to ensure fidelity share important conceptual analogies with those used by cellular machineries involved in DNA replication, transcription, and translation, and these mechanisms likely represent general principles for other complex cellular pathways.
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Affiliation(s)
- Xin Zhang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125;
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45
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Altegoer F, Schuhmacher J, Pausch P, Bange G. From molecular evolution to biobricks and synthetic modules: a lesson by the bacterial flagellum. Biotechnol Genet Eng Rev 2014; 30:49-64. [DOI: 10.1080/02648725.2014.921500] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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YlxM is a newly identified accessory protein that influences the function of signal recognition particle pathway components in Streptococcus mutans. J Bacteriol 2014; 196:2043-52. [PMID: 24659773 DOI: 10.1128/jb.01465-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Streptococcus mutans is a cariogenic oral pathogen whose virulence is determined largely by its membrane composition. The signal recognition particle (SRP) protein-targeting pathway plays a pivotal role in membrane biogenesis. S. mutans SRP pathway mutants demonstrate growth defects, cannot contend with environmental stress, and exhibit multiple changes in membrane composition. This study sought to define a role for ylxM, which in S. mutans and numerous other bacteria resides directly upstream of the ffh gene, encoding a major functional element of the bacterial SRP. YlxM was observed as a produced protein in S. mutans. Its predicted helix-turn-helix motif suggested that it has a role as a transcriptional regulator of components within the SRP pathway; however, no evidence of transcriptional regulation was found. Instead, capture enzyme-linked immunosorbent assay (ELISA), affinity chromatography, and bio-layer interferometry (BLI) demonstrated that S. mutans YlxM interacts with the SRP components Ffh and small cytoplasmic RNA (scRNA) but not with the SRP receptor FtsY. In the absence of FtsY, YlxM increased the GTP hydrolysis activity of Ffh alone and in complex with scRNA. However, in the presence of FtsY, YlxM caused an overall diminution of net GTPase activity. Thus, YlxM appears to modulate GTP hydrolysis, a process necessary for proper recycling of SRP pathway components. The presence of YlxM conferred a significant competitive growth advantage under nonstress and acid stress conditions when wild-type and ylxM mutant strains were cultured together. Our results identify YlxM as a component of the S. mutans SRP and suggest a regulatory function affecting GTPase activity.
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47
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Jang MS, Goo E, An JH, Kim J, Hwang I. Quorum sensing controls flagellar morphogenesis in Burkholderia glumae. PLoS One 2014; 9:e84831. [PMID: 24416296 PMCID: PMC3885665 DOI: 10.1371/journal.pone.0084831] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/19/2013] [Indexed: 12/30/2022] Open
Abstract
Burkholderia glumae is a motile plant pathogenic bacterium that has multiple polar flagella and one LuxR/LuxI-type quorum sensing (QS) system, TofR/TofI. A QS-dependent transcriptional regulator, QsmR, activates flagellar master regulator flhDC genes. FlhDC subsequently activates flagellar gene expression in B. glumae at 37°C. Here, we confirm that the interplay between QS and temperature is critical for normal polar flagellar morphogenesis in B. glumae. In the wild-type bacterium, flagellar gene expression and flagellar number were greater at 28°C compared to 37°C. The QS-dependent flhC gene was significantly expressed at 28°C in two QS-defective (tofI::Ω and qsmR::Ω) mutants. Thus, flagella were present in both tofI::Ω and qsmR::Ω mutants at 28°C, but were absent at 37°C. Most tofI::Ω and qsmR::Ω mutant cells possessed polar or nonpolar flagella at 28°C. Nonpolarly flagellated cells processing flagella around cell surface of both tofI::Ω and qsmR::Ω mutants exhibited tumbling and spinning movements. The flhF gene encoding GTPase involved in regulating the correct placement of flagella in other bacteria was expressed in QS mutants in a FlhDC-dependent manner at 28°C. However, FlhF was mislocalized in QS mutants, and was associated with nonpolar flagellar formation in QS mutants at 28°C. These results indicate that QS-independent expression of flagellar genes at 28°C allows flagellar biogenesis, but is not sufficient for normal polar flagellar morphogenesis in B. glumae. Our findings demonstrate that QS functions together with temperature to control flagellar morphogenesis in B. glumae.
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Affiliation(s)
- Moon Sun Jang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Eunhye Goo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Jae Hyung An
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Jinwoo Kim
- Division of Applied Life Science and Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju, Republic of Korea
| | - Ingyu Hwang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- * E-mail:
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Saraogi I, Shan SO. Co-translational protein targeting to the bacterial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1433-41. [PMID: 24513458 DOI: 10.1016/j.bbamcr.2013.10.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/09/2013] [Accepted: 10/16/2013] [Indexed: 12/18/2022]
Abstract
Co-translational protein targeting by the Signal Recognition Particle (SRP) is an essential cellular pathway that couples the synthesis of nascent proteins to their proper cellular localization. The bacterial SRP, which contains the minimal ribonucleoprotein core of this universally conserved targeting machine, has served as a paradigm for understanding the molecular basis of protein localization in all cells. In this review, we highlight recent biochemical and structural insights into the molecular mechanisms by which fundamental challenges faced by protein targeting machineries are met in the SRP pathway. Collectively, these studies elucidate how an essential SRP RNA and two regulatory GTPases in the SRP and SRP receptor (SR) enable this targeting machinery to recognize, sense and respond to its biological effectors, i.e. the cargo protein, the target membrane and the translocation machinery, thus driving efficient and faithful co-translational protein targeting. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Ishu Saraogi
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Shu-ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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SIMIBI twins in protein targeting and localization. Nat Struct Mol Biol 2013; 20:776-80. [DOI: 10.1038/nsmb.2605] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/07/2013] [Indexed: 12/31/2022]
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Kazmierczak BI, Hendrixson DR. Spatial and numerical regulation of flagellar biosynthesis in polarly flagellated bacteria. Mol Microbiol 2013; 88:655-63. [PMID: 23600726 DOI: 10.1111/mmi.12221] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2013] [Indexed: 12/20/2022]
Abstract
Control of surface organelle number and placement is a crucial aspect of the cell biology of many Gram-positive and Gram-negative bacteria, yet mechanistic insights into how bacteria spatially and numerically organize organelles are lacking. Many surface structures and internal complexes are spatially restricted in the bacterial cell (e.g. type IV pili, holdfasts, chemoreceptors), but perhaps none show so many distinct patterns in terms of number and localization as the flagellum. In this review, we discuss two proteins, FlhF and FlhG (also annotated FleN/YlxH), which control aspects of flagellar assembly, placement and number in polar flagellates, and may influence flagellation in some bacteria that produce peritrichous flagella. Experimental data obtained in a number of bacterial species suggest that these proteins may have acquired distinct attributes influencing flagellar assembly that reflect the diversity of flagellation patterns seen in different polar flagellates. Recent findings also suggest FlhF and FlhG are involved in other processes, such as influencing the rotation of flagella and proper cell division. Continued examination of these proteins in polar flagellates is expected to reveal how different bacteria have adapted FlhF or FlhG with specific activities to tailor flagellar biosynthesis and motility to fit the needs of each species.
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Affiliation(s)
- Barbara I Kazmierczak
- Departments of Medicine & Microbial Pathogenesis, Yale University School of Medicine, 333 Cedar St, New Haven, CT 06520-8022, USA.
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