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Charles-Orszag A, Petek-Seoane NA, Mullins RD. Archaeal actins and the origin of a multi-functional cytoskeleton. J Bacteriol 2024; 206:e0034823. [PMID: 38391233 PMCID: PMC10955848 DOI: 10.1128/jb.00348-23] [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] [Indexed: 02/24/2024] Open
Abstract
Actin and actin-like proteins form filamentous polymers that carry out important cellular functions in all domains of life. In this review, we sketch a map of the function and regulation of actin-like proteins across bacteria, archaea, and eukarya, marking some of the terra incognita that remain in this landscape. We focus particular attention on archaea because mapping the structure and function of cytoskeletal systems across this domain promises to help us understand the evolutionary relationship between the (mostly) mono-functional actin-like filaments found in bacteria and the multi-functional actin cytoskeletons that characterize eukaryotic cells.
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Affiliation(s)
- Arthur Charles-Orszag
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA
| | - Natalie A. Petek-Seoane
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA
| | - R. Dyche Mullins
- Department of Cellular and Molecular Pharmacology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA
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2
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Zheng J, Mallon J, Lammers A, Rados T, Litschel T, Moody ERR, Ramirez-Diaz DA, Schmid A, Williams TA, Bisson-Filho AW, Garner E. Salactin, a dynamically unstable actin homolog in Haloarchaea. mBio 2023; 14:e0227223. [PMID: 37966230 PMCID: PMC10746226 DOI: 10.1128/mbio.02272-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 10/05/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE Protein filaments play important roles in many biological processes. We discovered an actin homolog in halophilic archaea, which we call Salactin. Just like the filaments that segregate DNA in eukaryotes, Salactin grows out of the cell poles towards the middle, and then quickly depolymerizes, a behavior known as dynamic instability. Furthermore, we see that Salactin affects the distribution of DNA in daughter cells when cells are grown in low-phosphate media, suggesting Salactin filaments might be involved in segregating DNA when the cell has only a few copies of the chromosome.
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Affiliation(s)
- Jenny Zheng
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - John Mallon
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Alex Lammers
- Physiology Course, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
- Department of Biomedical Engineering, The Biological Design Center, Boston University, Boston, Massachusetts, USA
- The Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, USA
| | - Theopi Rados
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Thomas Litschel
- Physiology Course, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Edmund R. R. Moody
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
| | - Diego A. Ramirez-Diaz
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Amy Schmid
- Department of Biology, Duke University, Durham, North Carolina, USA
- Center for Genomics and Computational Biology, Duke University, Durham, North Carolina, USA
| | - Tom A. Williams
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Alexandre W. Bisson-Filho
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Ethan Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
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3
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Arboleda-García A, Alarcon-Ruiz I, Boada-Acosta L, Boada Y, Vignoni A, Jantus-Lewintre E. Advancements in synthetic biology-based bacterial cancer therapy: A modular design approach. Crit Rev Oncol Hematol 2023; 190:104088. [PMID: 37541537 DOI: 10.1016/j.critrevonc.2023.104088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/18/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023] Open
Abstract
Synthetic biology aims to program living bacteria cells with artificial genetic circuits for user-defined functions, transforming them into powerful tools with numerous applications in various fields, including oncology. Cancer treatments have serious side effects on patients due to the systemic action of the drugs involved. To address this, new systems that provide localized antitumoral action while minimizing damage to healthy tissues are required. Bacteria, often considered pathogenic agents, have been used as cancer treatments since the early 20th century. Advances in genetic engineering, synthetic biology, microbiology, and oncology have improved bacterial therapies, making them safer and more effective. Here we propose six modules for a successful synthetic biology-based bacterial cancer therapy, the modules include Payload, Release, Tumor-targeting, Biocontainment, Memory, and Genetic Circuit Stability Module. These will ensure antitumor activity, safety for the environment and patient, prevent bacterial colonization, maintain cell stability, and prevent loss or defunctionalization of the genetic circuit.
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Affiliation(s)
- Andrés Arboleda-García
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain
| | - Ivan Alarcon-Ruiz
- Gene Regulation in Cardiovascular Remodeling and Inflammation Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lissette Boada-Acosta
- Centro de Investigación Biomédica en Red Cáncer, CIBERONC, Madrid, Spain; TRIAL Mixed Unit, Centro de Investigación Príncipe Felipe-Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Molecular Oncology Laboratory, Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain
| | - Yadira Boada
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain
| | - Alejandro Vignoni
- Systems Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, Spain.
| | - Eloisa Jantus-Lewintre
- Centro de Investigación Biomédica en Red Cáncer, CIBERONC, Madrid, Spain; TRIAL Mixed Unit, Centro de Investigación Príncipe Felipe-Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Molecular Oncology Laboratory, Fundación Investigación del Hospital General Universitario de Valencia, Valencia, Spain; Department of Biotechnology, Universitat Politècnica de València, Valencia, Spain
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4
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Geelhoed JS, Thorup CA, Bjerg JJ, Schreiber L, Nielsen LP, Schramm A, Meysman FJR, Marshall IPG. Indications for a genetic basis for big bacteria and description of the giant cable bacterium Candidatus Electrothrix gigas sp. nov. Microbiol Spectr 2023; 11:e0053823. [PMID: 37732806 PMCID: PMC10580974 DOI: 10.1128/spectrum.00538-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/21/2023] [Indexed: 09/22/2023] Open
Abstract
Bacterial cells can vary greatly in size, from a few hundred nanometers to hundreds of micrometers in diameter. Filamentous cable bacteria also display substantial size differences, with filament diameters ranging from 0.4 to 8 µm. We analyzed the genomes of cable bacterium filaments from 11 coastal environments of which the resulting 23 new genomes represent 10 novel species-level clades of Candidatus Electrothrix and two clades that putatively represent novel genus-level diversity. Fluorescence in situ hybridization with a species-level probe showed that large-sized cable bacteria belong to a novel species with the proposed name Ca. Electrothrix gigas. Comparative genome analysis suggests genes that play a role in the construction or functioning of large cable bacteria cells: the genomes of Ca. Electrothrix gigas encode a novel actin-like protein as well as a species-specific gene cluster encoding four putative pilin proteins and a putative type II secretion platform protein, which are not present in other cable bacteria. The novel actin-like protein was also found in a number of other giant bacteria, suggesting there could be a genetic basis for large cell size. This actin-like protein (denoted big bacteria protein, Bbp) may have a function analogous to other actin proteins in cell structure or intracellular transport. We contend that Bbp may help overcome the challenges of diffusion limitation and/or morphological complexity presented by the large cells of Ca. Electrothrix gigas and other giant bacteria. IMPORTANCE In this study, we substantially expand the known diversity of marine cable bacteria and describe cable bacteria with a large diameter as a novel species with the proposed name Candidatus Electrothrix gigas. In the genomes of this species, we identified a gene that encodes a novel actin-like protein [denoted big bacteria protein (Bbp)]. The bbp gene was also found in a number of other giant bacteria, predominantly affiliated to Desulfobacterota and Gammaproteobacteria, indicating that there may be a genetic basis for large cell size. Thus far, mostly structural adaptations of giant bacteria, vacuoles, and other inclusions or organelles have been observed, which are employed to overcome nutrient diffusion limitation in their environment. In analogy to other actin proteins, Bbp could fulfill a structural role in the cell or potentially facilitate intracellular transport.
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Affiliation(s)
- Jeanine S. Geelhoed
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
| | - Casper A. Thorup
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Jesper J. Bjerg
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Lars Schreiber
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Lars Peter Nielsen
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Filip J. R. Meysman
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
| | - Ian P. G. Marshall
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
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Liao YC, Saengsawang B, Chen JW, Zhuo XZ, Li SY. Construction of an Antibiotic-Free Vector and its Application in the Metabolic Engineering of Escherichia Coli for Polyhydroxybutyrate Production. Front Bioeng Biotechnol 2022; 10:837944. [PMID: 35721860 PMCID: PMC9204107 DOI: 10.3389/fbioe.2022.837944] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
An antibiotic- and inducer-free culture condition was proposed for polyhydroxybutyrate (PHB) production in recombinant Escherichia coli. First, antibiotic-free vectors were constructed by installing the plasmid maintenance system, alp7, hok/sok, and the hok/sok and alp7 combination into the pUC19 vector. The plasmid stability test showed that pVEC02, the pUC19 vector containing the hok/sok system, was the most effective in achieving antibiotic-free cultivation in the E. coli B strain but not in the K strain. Second, the putative phaCAB operon derived from Caldimonas manganoxidans was inserted into pVEC02 to yield pPHB01 for PHB production in E. coli BL21 (DE3). The putative phaCAB operon was first shown function properly for PHB production and thus, inducer-free conditions were achieved. However, the maintenance of pPHB01 in E. coli requires antibiotics supplementation. Finally, an efficient E. coli ρ factor-independent terminator, thrLABC (ECK120033737), was inserted between the phaCAB operon and the hok/sok system to avoid possible transcriptional carry-over. The newly constructed plasmid pPHB01-1 facilitates an antibiotic- and inducer-free culture condition and induces the production of PHB with a concentration of 3.0 on0.2 g/L, yield of 0.26 /L0.07 g/g-glucose, and content of 44 /g3%. The PHB production using E. coli BL21 (DE3)/pPHB01-1 has been shown to last 84 and 96 h in the liquid and solid cultures.
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Affiliation(s)
- Ying-Cheng Liao
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
| | - Boonyawee Saengsawang
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
| | - Jun-Wei Chen
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
| | - Xiao-Zhen Zhuo
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
| | - Si-Yu Li
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, Taiwan
- *Correspondence: Si-Yu Li,
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6
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Mishra D, Srinivasan R. Catching a Walker in the Act-DNA Partitioning by ParA Family of Proteins. Front Microbiol 2022; 13:856547. [PMID: 35694299 PMCID: PMC9178275 DOI: 10.3389/fmicb.2022.856547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/28/2022] [Indexed: 12/01/2022] Open
Abstract
Partitioning the replicated genetic material is a crucial process in the cell cycle program of any life form. In bacteria, many plasmids utilize cytoskeletal proteins that include ParM and TubZ, the ancestors of the eukaryotic actin and tubulin, respectively, to segregate the plasmids into the daughter cells. Another distinct class of cytoskeletal proteins, known as the Walker A type Cytoskeletal ATPases (WACA), is unique to Bacteria and Archaea. ParA, a WACA family protein, is involved in DNA partitioning and is more widespread. A centromere-like sequence parS, in the DNA is bound by ParB, an adaptor protein with CTPase activity to form the segregation complex. The ParA ATPase, interacts with the segregation complex and partitions the DNA into the daughter cells. Furthermore, the Walker A motif-containing ParA superfamily of proteins is associated with a diverse set of functions ranging from DNA segregation to cell division, cell polarity, chemotaxis cluster assembly, cellulose biosynthesis and carboxysome maintenance. Unifying principles underlying the varied range of cellular roles in which the ParA superfamily of proteins function are outlined. Here, we provide an overview of the recent findings on the structure and function of the ParB adaptor protein and review the current models and mechanisms by which the ParA family of proteins function in the partitioning of the replicated DNA into the newly born daughter cells.
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Affiliation(s)
- Dipika Mishra
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India
- Homi Bhabha National Institutes, Mumbai, India
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, India
- Homi Bhabha National Institutes, Mumbai, India
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7
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Val-Calvo J, Miguel-Arribas A, Abia D, Wu LJ, Meijer WJJ. pLS20 is the archetype of a new family of conjugative plasmids harboured by Bacillus species. NAR Genom Bioinform 2021; 3:lqab096. [PMID: 34729475 PMCID: PMC8557374 DOI: 10.1093/nargab/lqab096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/03/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022] Open
Abstract
Conjugation plays important roles in genome plasticity, adaptation and evolution but is also the major horizontal gene-transfer route responsible for spreading toxin, virulence and antibiotic resistance genes. A better understanding of the conjugation process is required for developing drugs and strategies to impede the conjugation-mediated spread of these genes. So far, only a limited number of conjugative elements have been studied. For most of them, it is not known whether they represent a group of conjugative elements, nor about their distribution patterns. Here we show that pLS20 from the Gram-positive bacterium Bacillus subtilis is the prototype conjugative plasmid of a family of at least 35 members that can be divided into four clades, and which are harboured by different Bacillus species found in different global locations and environmental niches. Analyses of their phylogenetic relationship and their conjugation operons have expanded our understanding of a family of conjugative plasmids of Gram-positive origin.
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Affiliation(s)
- Jorge Val-Calvo
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - Andrés Miguel-Arribas
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - David Abia
- Bioinformatics Facility, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Wilfried J J Meijer
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), C. Nicolás Cabrera 1, Universidad Autónoma de Madrid, Canto Blanco, 28049, Madrid, Spain
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8
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Meijer WJJ, Boer DR, Ares S, Alfonso C, Rojo F, Luque-Ortega JR, Wu LJ. Multiple Layered Control of the Conjugation Process of the Bacillus subtilis Plasmid pLS20. Front Mol Biosci 2021; 8:648468. [PMID: 33816561 PMCID: PMC8014075 DOI: 10.3389/fmolb.2021.648468] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 02/08/2021] [Indexed: 11/24/2022] Open
Abstract
Bacterial conjugation is the main horizontal gene transfer route responsible for the spread of antibiotic resistance, virulence and toxin genes. During conjugation, DNA is transferred from a donor to a recipient cell via a sophisticated channel connecting the two cells. Conjugation not only affects many different aspects of the plasmid and the host, ranging from the properties of the membrane and the cell surface of the donor, to other developmental processes such as competence, it probably also poses a burden on the donor cell due to the expression of the large number of genes involved in the conjugation process. Therefore, expression of the conjugation genes must be strictly controlled. Over the past decade, the regulation of the conjugation genes present on the conjugative Bacillus subtilis plasmid pLS20 has been studied using a variety of methods including genetic, biochemical, biophysical and structural approaches. This review focuses on the interplay between RcopLS20, RappLS20 and Phr*pLS20, the proteins that control the activity of the main conjugation promoter Pc located upstream of the conjugation operon. Proper expression of the conjugation genes requires the following two fundamental elements. First, conjugation is repressed by default and an intercellular quorum-signaling system is used to sense conditions favorable for conjugation. Second, different layers of regulation act together to repress the Pc promoter in a strict manner but allowing rapid activation. During conjugation, ssDNA is exported from the cell by a membrane-embedded DNA translocation machine. Another membrane-embedded DNA translocation machine imports ssDNA in competent cells. Evidences are reviewed indicating that conjugation and competence are probably mutually exclusive processes. Some of the questions that remain unanswered are discussed.
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Affiliation(s)
- Wilfried J J Meijer
- Laboratory 402, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, Canto Blanco, Madrid, Spain
| | | | - Saúl Ares
- Laboratory 35, C. Grupo Interdisciplinar de Sistemas Complejos and Departamento de Biología de Sistemas, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Carlos Alfonso
- Laboratory B08, Systems Biochemistry of Bacterial Division Lab, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Fernando Rojo
- Laboratory 216, Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Juan R Luque-Ortega
- Laboratory S07, Molecular Interactions Facility, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, United Kingdom
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Gupta CM, Ambaru B, Bajaj R. Emerging Functions of Actins and Actin Binding Proteins in Trypanosomatids. Front Cell Dev Biol 2020; 8:587685. [PMID: 33163497 PMCID: PMC7581878 DOI: 10.3389/fcell.2020.587685] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/22/2020] [Indexed: 01/20/2023] Open
Abstract
Actin is the major protein constituent of the cytoskeleton that performs wide range of cellular functions. It exists in monomeric and filamentous forms, dynamics of which is regulated by a large repertoire of actin binding proteins. However, not much was known about existence of these proteins in trypanosomatids, till the genome sequence data of three important organisms of this class, viz. Trypanosoma brucei, Trypanosoma cruzi and Leishmania major, became available. Here, we have reviewed most of the findings reported to date on the intracellular distribution, structure and functions of these proteins and based on them, we have hypothesized some of their functions. The major findings are as follows: (1) All the three organisms encode at least a set of ten actin binding proteins (profilin, twinfilin, ADF/cofilin, CAP/srv2, CAPz, coronin, two myosins, two formins) and one isoform of actin, except that T. cruzi encodes for three formins and several myosins along with four actins. (2) Actin 1 and a few actin binding proteins (ADF/cofilin, profilin, twinfilin, coronin and myosin13 in L. donovani; ADF/cofilin, profilin and myosin1 in T. brucei; profilin and myosin-F in T.cruzi) have been identified and characterized. (3) In all the three organisms, actin cytoskeleton has been shown to regulate endocytosis and intracellular trafficking. (4) Leishmania actin1 has been the most characterized protein among trypanosomatid actins. (5) This protein is localized to the cytoplasm as well as in the flagellum, nucleus and kinetoplast, and in vitro, it binds to DNA and displays scDNA relaxing and kDNA nicking activities. (6) The pure protein prefers to form bundles instead of thin filaments, and does not bind DNase1 or phalloidin. (7) Myosin13, myosin1 and myosin-F regulate endocytosis and intracellular trafficking, respectively, in Leishmania, T. brucei and T. cruzi. (8) Actin-dependent myosin13 motor is involved in dynamics and assembly of Leishmania flagellum. (9) Leishmania twinfilin localizes mostly to the nucleolus and coordinates karyokinesis by effecting splindle elongation and DNA synthesis. (10) Leishmania coronin binds and promotes actin filament formation and exists in tetrameric form rather than trimeric form, like other coronins. (11) Trypanosomatid profilins are essential for survival of all the three parasites.
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Affiliation(s)
- Chhitar M Gupta
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru, India
| | - Bindu Ambaru
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru, India.,Manipal Academy of Higher Education, Manipal, India
| | - Rani Bajaj
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru, India.,Manipal Academy of Higher Education, Manipal, India
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10
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Oral delivery of bacteria: Basic principles and biomedical applications. J Control Release 2020; 327:801-833. [DOI: 10.1016/j.jconrel.2020.09.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/05/2020] [Indexed: 12/18/2022]
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11
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020. [PMID: 31900730 DOI: 10.1007/s00709-019-01442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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12
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020; 257:621-753. [PMID: 31900730 PMCID: PMC7203096 DOI: 10.1007/s00709-019-01442-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/19/2019] [Indexed: 05/02/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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13
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Abstract
Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the bacterial cell has been examined for about two decades; typically, they are not randomly distributed, and their positioning depends on copy number and their mode of segregation. Low-copy-number plasmids promote their own stable inheritance in their bacterial hosts by encoding active partition systems, which ensure that copies are positioned in both halves of a dividing cell. High-copy plasmids rely on passive diffusion of some copies, but many remain clustered together in the nucleoid-free regions of the cell. Here we review plasmid localization and partition (Par) systems, with particular emphasis on plasmids from Enterobacteriaceae and on recent results describing the in vivo localization properties and molecular mechanisms of each system. Partition systems also cause plasmid incompatibility such that distinct plasmids (with different replicons) with the same Par system cannot be stably maintained in the same cells. We discuss how partition-mediated incompatibility is a consequence of the partition mechanism.
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14
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Val-Calvo J, Luque-Ortega JR, Crespo I, Miguel-Arribas A, Abia D, Sánchez-Hevia DL, Serrano E, Gago-Córdoba C, Ares S, Alfonso C, Rojo F, Wu LJ, Boer DR, Meijer WJJ. Novel regulatory mechanism of establishment genes of conjugative plasmids. Nucleic Acids Res 2019; 46:11910-11926. [PMID: 30380104 PMCID: PMC6294495 DOI: 10.1093/nar/gky996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
The principal route for dissemination of antibiotic resistance genes is conjugation by which a conjugative DNA element is transferred from a donor to a recipient cell. Conjugative elements contain genes that are important for their establishment in the new host, for instance by counteracting the host defense mechanisms acting against incoming foreign DNA. Little is known about these establishment genes and how they are regulated. Here, we deciphered the regulation mechanism of possible establishment genes of plasmid p576 from the Gram-positive bacterium Bacillus pumilus. Unlike the ssDNA promoters described for some conjugative plasmids, the four promoters of these p576 genes are repressed by a repressor protein, which we named Reg576. Reg576 also regulates its own expression. After transfer of the DNA, these genes are de-repressed for a period of time until sufficient Reg576 is synthesized to repress the promoters again. Complementary in vivo and in vitro analyses showed that different operator configurations in the promoter regions of these genes lead to different responses to Reg576. Each operator is bound with extreme cooperativity by two Reg576-dimers. The X-ray structure revealed that Reg576 has a Ribbon-Helix-Helix core and provided important insights into the high cooperativity of DNA recognition.
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Affiliation(s)
- Jorge Val-Calvo
- Department of Virology and Microbiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Instituto de Biología Molecular "Eladio Viñuela" (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - Juan R Luque-Ortega
- Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Isidro Crespo
- ALBA Synchrotron Light Source, Carrer de la Llum 2-26, Cerdanyola del Vallès, Barcelona 08290, Spain
| | - Andrés Miguel-Arribas
- Department of Virology and Microbiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Instituto de Biología Molecular "Eladio Viñuela" (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - David Abia
- Bioinformatics Facility, Centro de Biología Molecular "Severo Ochoa"
| | | | - Ester Serrano
- Department of Virology and Microbiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Instituto de Biología Molecular "Eladio Viñuela" (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - César Gago-Córdoba
- Department of Virology and Microbiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Instituto de Biología Molecular "Eladio Viñuela" (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
| | - Saúl Ares
- Centro Nacional de Biotecnología (CSIC), Darwin 3, 28049 Madrid, Spain.,Grupo Interdisciplinar de Sistemas Complejos (GISC) and Departamento de Matemáticas, Universidad Carlos III de Madrid, 28911 Leganes, Spain
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Fernando Rojo
- Centro Nacional de Biotecnología (CSIC), Darwin 3, 28049 Madrid, Spain
| | - Ling J Wu
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle Upon Tyne, NE4AX, UK
| | - D Roeland Boer
- ALBA Synchrotron Light Source, Carrer de la Llum 2-26, Cerdanyola del Vallès, Barcelona 08290, Spain
| | - Wilfried J J Meijer
- Department of Virology and Microbiology, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Instituto de Biología Molecular "Eladio Viñuela" (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain
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Abstract
ABSTRACT
The clostridia cause a spectrum of diseases in humans and animals ranging from life-threatening tetanus and botulism, uterine infections, histotoxic infections and enteric diseases, including antibiotic-associated diarrhea, and food poisoning. The symptoms of all these diseases are the result of potent protein toxins produced by these organisms. These toxins are diverse, ranging from a multitude of pore-forming toxins to phospholipases, metalloproteases, ADP-ribosyltransferases and large glycosyltransferases. The location of the toxin genes is the unifying theme of this review because with one or two exceptions they are all located on plasmids or on bacteriophage that replicate using a plasmid-like intermediate. Some of these plasmids are distantly related whilst others share little or no similarity. Many of these toxin plasmids have been shown to be conjugative. The mobile nature of these toxin genes gives a ready explanation of how clostridial toxin genes have been so widely disseminated both within the clostridial genera as well as in the wider bacterial community.
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Hürtgen D, Vogel SK, Schwille P. Cytoskeletal and Actin-Based Polymerization Motors and Their Role in Minimal Cell Design. ACTA ACUST UNITED AC 2019; 3:e1800311. [PMID: 32648711 DOI: 10.1002/adbi.201800311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/28/2019] [Indexed: 01/28/2023]
Abstract
Life implies motion. In cells, protein-based active molecular machines drive cell locomotion and intracellular transport, control cell shape, segregate genetic material, and split a cell in two parts. Key players among molecular machines driving these various cell functions are the cytoskeleton and motor proteins that convert chemical bound energy into mechanical work. Findings over the last decades in the field of in vitro reconstitutions of cytoskeletal and motor proteins have elucidated mechanistic details of these active protein systems. For example, a complex spatial and temporal interplay between the cytoskeleton and motor proteins is responsible for the translation of chemically bound energy into (directed) movement and force generation, which eventually governs the emergence of complex cellular functions. Understanding these mechanisms and the design principles of the cytoskeleton and motor proteins builds the basis for mimicking fundamental life processes. Here, a brief overview of actin, prokaryotic actin analogs, and motor proteins and their potential role in the design of a minimal cell from the bottom-up is provided.
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Affiliation(s)
- Daniel Hürtgen
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (Synmikro), D-35043, Marburg, Germany
| | - Sven Kenjiro Vogel
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry , Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry , Am Klopferspitz 18, D-82152, Martinsried, Germany
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17
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Barvitenko N, Lawen A, Aslam M, Pantaleo A, Saldanha C, Skverchinskaya E, Regolini M, Tuszynski JA. Integration of intracellular signaling: Biological analogues of wires, processors and memories organized by a centrosome 3D reference system. Biosystems 2018; 173:191-206. [PMID: 30142359 DOI: 10.1016/j.biosystems.2018.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/03/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Myriads of signaling pathways in a single cell function to achieve the highest spatio-temporal integration. Data are accumulating on the role of electromechanical soliton-like waves in signal transduction processes. Theoretical studies strongly suggest feasibility of both classical and quantum computing involving microtubules. AIM A theoretical study of the role of the complex composed of the plasma membrane and the microtubule-based cytoskeleton as a system that transmits, stores and processes information. METHODS Theoretical analysis presented here refers to (i) the Penrose-Hameroff theory of consciousness (Orchestrated Objective Reduction; Orch OR), (ii) the description of the centrosome as a reference system for construction of the 3D map of the cell proposed by Regolini, (iii) the Heimburg-Jackson model of the nerve pulse propagation along axons' lipid bilayer as soliton-like electro-mechanical waves. RESULTS AND CONCLUSION The ideas presented in this paper provide a qualitative model for the decision-making processes in a living cell undergoing a differentiation process. OUTLOOK This paper paves the way for the real-time live-cell observation of information processing by microtubule-based cytoskeleton and cell fate decision making.
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Affiliation(s)
| | - Alfons Lawen
- Monash University, School of Biomedical Sciences, Department of Biochemistry and Molecular Biology, VIC, 3800, Australia
| | - Muhammad Aslam
- Medical Clininc I, Cardiology/Angiology, University Hospital, Justus-Liebig-University, Giessen, Germany
| | - Antonella Pantaleo
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Carlota Saldanha
- Instituto de Medicina Molecular, Instituto de Bioquimica, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | | | - Marco Regolini
- Department of Bioengineering and Mathematical Modeling, AudioLogic, Milan, Italy
| | - Jack A Tuszynski
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada; Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128, Torino, Italy.
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18
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LaSarre B, Kysela DT, Stein BD, Ducret A, Brun YV, McKinlay JB. Restricted Localization of Photosynthetic Intracytoplasmic Membranes (ICMs) in Multiple Genera of Purple Nonsulfur Bacteria. mBio 2018; 9:e00780-18. [PMID: 29970460 PMCID: PMC6030561 DOI: 10.1128/mbio.00780-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/06/2018] [Indexed: 01/18/2023] Open
Abstract
In bacteria and eukaryotes alike, proper cellular physiology relies on robust subcellular organization. For the phototrophic purple nonsulfur bacteria (PNSB), this organization entails the use of a light-harvesting, membrane-bound compartment known as the intracytoplasmic membrane (ICM). Here we show that ICMs are spatially and temporally localized in diverse patterns among PNSB. We visualized ICMs in live cells of 14 PNSB species across nine genera by exploiting the natural autofluorescence of the photosynthetic pigment bacteriochlorophyll (BChl). We then quantitatively characterized ICM localization using automated computational analysis of BChl fluorescence patterns within single cells across the population. We revealed that while many PNSB elaborate ICMs along the entirety of the cell, species across as least two genera restrict ICMs to discrete, nonrandom sites near cell poles in a manner coordinated with cell growth and division. Phylogenetic and phenotypic comparisons established that ICM localization and ICM architecture are not strictly interdependent and that neither trait fully correlates with the evolutionary relatedness of the species. The natural diversity of ICM localization revealed herein has implications for both the evolution of phototrophic organisms and their light-harvesting compartments and the mechanisms underpinning spatial organization of bacterial compartments.IMPORTANCE Many bacteria organize their cellular space by constructing subcellular compartments that are arranged in specific, physiologically relevant patterns. The purple nonsulfur bacteria (PNSB) utilize a membrane-bound compartment known as the intracytoplasmic membrane (ICM) to harvest light for photosynthesis. It was previously unknown whether ICM localization within cells is systematic or irregular and if ICM localization is conserved among PNSB. Here we surveyed ICM localization in diverse PNSB and show that ICMs are spatially organized in species-specific patterns. Most strikingly, several PNSB resolutely restrict ICMs to regions near the cell poles, leaving much of the cell devoid of light-harvesting machinery. Our results demonstrate that bacteria of a common lifestyle utilize unequal portions of their intracellular space to harvest light, despite light harvesting being a process that is intuitively influenced by surface area. Our findings therefore raise fundamental questions about ICM biology and evolution.
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Affiliation(s)
- Breah LaSarre
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - David T Kysela
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Barry D Stein
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Adrien Ducret
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Yves V Brun
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - James B McKinlay
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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19
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Pollard TD, Goldman RD. Overview of the Cytoskeleton from an Evolutionary Perspective. Cold Spring Harb Perspect Biol 2018; 10:10/7/a030288. [PMID: 29967009 DOI: 10.1101/cshperspect.a030288] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Organisms in the three domains of life depend on protein polymers to form a cytoskeleton that helps to establish their shapes, maintain their mechanical integrity, divide, and, in many cases, move. Eukaryotes have the most complex cytoskeletons, comprising three cytoskeletal polymers-actin filaments, intermediate filaments, and microtubules-acted on by three families of motor proteins (myosin, kinesin, and dynein). Prokaryotes have polymers of proteins homologous to actin and tubulin but no motors, and a few bacteria have a protein related to intermediate filament proteins.
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Affiliation(s)
- Thomas D Pollard
- Departments of Molecular Cellular and Developmental Biology, Molecular Biophysics and Biochemistry, and Cell Biology, Yale University, New Haven, Connecticut 06520-8103
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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20
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Szewczak-Harris A, Löwe J. Cryo-EM reconstruction of AlfA from Bacillus subtilis reveals the structure of a simplified actin-like filament at 3.4-Å resolution. Proc Natl Acad Sci U S A 2018; 115:3458-3463. [PMID: 29440489 PMCID: PMC5879667 DOI: 10.1073/pnas.1716424115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Low copy-number plasmid pLS32 of Bacillus subtilis subsp. natto contains a partitioning system that ensures segregation of plasmid copies during cell division. The partitioning locus comprises actin-like protein AlfA, adaptor protein AlfB, and the centromeric sequence parN Similar to the ParMRC partitioning system from Escherichia coli plasmid R1, AlfA filaments form actin-like double helical filaments that arrange into an antiparallel bipolar spindle, which attaches its growing ends to sister plasmids through interactions with AlfB and parN Because, compared with ParM and other actin-like proteins, AlfA is highly diverged in sequence, we determined the atomic structure of nonbundling AlfA filaments to 3.4-Å resolution by cryo-EM. The structure reveals how the deletion of subdomain IIB of the canonical actin fold has been accommodated by unique longitudinal and lateral contacts, while still enabling formation of left-handed, double helical, polar and staggered filaments that are architecturally similar to ParM. Through cryo-EM reconstruction of bundling AlfA filaments, we obtained a pseudoatomic model of AlfA doublets: the assembly of two filaments. The filaments are antiparallel, as required by the segregation mechanism, and exactly antiphasic with near eightfold helical symmetry, to enable efficient doublet formation. The structure of AlfA filaments and doublets shows, in atomic detail, how deletion of an entire domain of the actin fold is compensated by changes to all interfaces so that the required properties of polymerization, nucleotide hydrolysis, and antiparallel doublet formation are retained to fulfill the system's biological raison d'être.
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Affiliation(s)
| | - Jan Löwe
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
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21
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The complex simplicity of the bacterial cytoskeleton. Proc Natl Acad Sci U S A 2018; 115:3205-3206. [PMID: 29549153 DOI: 10.1073/pnas.1801783115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Cryo-EM structure of the bacterial actin AlfA reveals unique assembly and ATP-binding interactions and the absence of a conserved subdomain. Proc Natl Acad Sci U S A 2018; 115:3356-3361. [PMID: 29440491 DOI: 10.1073/pnas.1715836115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial actins are an evolutionarily diverse family of ATP-dependent filaments built from protomers with a conserved structural fold. Actin-based segregation systems are encoded on many bacterial plasmids and function to partition plasmids into daughter cells. The bacterial actin AlfA segregates plasmids by a mechanism distinct from other partition systems, dependent on its unique dynamic properties. Here, we report the near-atomic resolution electron cryo-microscopy structure of the AlfA filament, which reveals a strikingly divergent filament architecture resulting from the loss of a subdomain conserved in all other actins and a mode of ATP binding. Its unusual assembly interfaces and nucleotide interactions provide insight into AlfA dynamics, and expand the range of evolutionary variation accessible to actin quaternary structure.
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23
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Wagstaff J, Löwe J. Prokaryotic cytoskeletons: protein filaments organizing small cells. Nat Rev Microbiol 2018; 16:187-201. [PMID: 29355854 DOI: 10.1038/nrmicro.2017.153] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Most, if not all, bacterial and archaeal cells contain at least one protein filament system. Although these filament systems in some cases form structures that are very similar to eukaryotic cytoskeletons, the term 'prokaryotic cytoskeletons' is used to refer to many different kinds of protein filaments. Cytoskeletons achieve their functions through polymerization of protein monomers and the resulting ability to access length scales larger than the size of the monomer. Prokaryotic cytoskeletons are involved in many fundamental aspects of prokaryotic cell biology and have important roles in cell shape determination, cell division and nonchromosomal DNA segregation. Some of the filament-forming proteins have been classified into a small number of conserved protein families, for example, the almost ubiquitous tubulin and actin superfamilies. To understand what makes filaments special and how the cytoskeletons they form enable cells to perform essential functions, the structure and function of cytoskeletal molecules and their filaments have been investigated in diverse bacteria and archaea. In this Review, we bring these data together to highlight the diverse ways that linear protein polymers can be used to organize other molecules and structures in bacteria and archaea.
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Affiliation(s)
- James Wagstaff
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Jan Löwe
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
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24
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Stoddard PR, Williams TA, Garner E, Baum B. Evolution of polymer formation within the actin superfamily. Mol Biol Cell 2017; 28:2461-2469. [PMID: 28904122 PMCID: PMC5597319 DOI: 10.1091/mbc.e15-11-0778] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/13/2017] [Accepted: 07/18/2017] [Indexed: 01/02/2023] Open
Abstract
While many are familiar with actin as a well-conserved component of the eukaryotic cytoskeleton, it is less often appreciated that actin is a member of a large superfamily of structurally related protein families found throughout the tree of life. Actin-related proteins include chaperones, carbohydrate kinases, and other enzymes, as well as a staggeringly diverse set of proteins that use the energy from ATP hydrolysis to form dynamic, linear polymers. Despite differing widely from one another in filament structure and dynamics, these polymers play important roles in ordering cell space in bacteria, archaea, and eukaryotes. It is not known whether these polymers descended from a single ancestral polymer or arose multiple times by convergent evolution from monomeric actin-like proteins. In this work, we provide an overview of the structures, dynamics, and functions of this diverse set. Then, using a phylogenetic analysis to examine actin evolution, we show that the actin-related protein families that form polymers are more closely related to one another than they are to other nonpolymerizing members of the actin superfamily. Thus all the known actin-like polymers are likely to be the descendants of a single, ancestral, polymer-forming actin-like protein.
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Affiliation(s)
- Patrick R Stoddard
- Molecular and Cellular Biology, Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Ethan Garner
- Molecular and Cellular Biology, Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138
| | - Buzz Baum
- MRC-Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- Institute of Physics of Living Systems, University College London, London WC1E 6BT, UK
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25
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Forde AJ, Albrecht N, Klingl A, Donovan C, Bramkamp M. Polymerization Dynamics of the Prophage-Encoded Actin-Like Protein AlpC Is Influenced by the DNA-Binding Adapter AlpA. Front Microbiol 2017; 8:1429. [PMID: 28824563 PMCID: PMC5539076 DOI: 10.3389/fmicb.2017.01429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/14/2017] [Indexed: 11/13/2022] Open
Abstract
The Corynebacterium glutamicum ATCC 13032 prophage CGP3 encodes an actin-like protein, AlpC that was shown to be involved in viral DNA transport and efficient viral DNA replication. AlpC binds to an adapter, AlpA that in turn binds to specific DNA sequences, termed alpS sites. Thus, the AlpAC system is similar to the known plasmid segregation system ParMRS. So far it is unclear how the AlpACS system mediates DNA transport and, whether AlpA and AlpC functionally interact. We show here that AlpA modulates AlpC filamentation dynamics in a dual way. Unbound AlpA stimulates AlpC filament disassembly, while AlpA bound to alpS sites allows for AlpC filament formation. Based on these results we propose a simple search and capture model that explains DNA segregation by viral AlpACS DNA segregation system.
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26
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van Teeseling MCF, de Pedro MA, Cava F. Determinants of Bacterial Morphology: From Fundamentals to Possibilities for Antimicrobial Targeting. Front Microbiol 2017; 8:1264. [PMID: 28740487 PMCID: PMC5502672 DOI: 10.3389/fmicb.2017.01264] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/23/2017] [Indexed: 12/11/2022] Open
Abstract
Bacterial morphology is extremely diverse. Specific shapes are the consequence of adaptive pressures optimizing bacterial fitness. Shape affects critical biological functions, including nutrient acquisition, motility, dispersion, stress resistance and interactions with other organisms. Although the characteristic shape of a bacterial species remains unchanged for vast numbers of generations, periodical variations occur throughout the cell (division) and life cycles, and these variations can be influenced by environmental conditions. Bacterial morphology is ultimately dictated by the net-like peptidoglycan (PG) sacculus. The species-specific shape of the PG sacculus at any time in the cell cycle is the product of multiple determinants. Some morphological determinants act as a cytoskeleton to guide biosynthetic complexes spatiotemporally, whereas others modify the PG sacculus after biosynthesis. Accumulating evidence supports critical roles of morphogenetic processes in bacteria-host interactions, including pathogenesis. Here, we review the molecular determinants underlying morphology, discuss the evidence linking bacterial morphology to niche adaptation and pathogenesis, and examine the potential of morphological determinants as antimicrobial targets.
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Affiliation(s)
- Muriel C F van Teeseling
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
| | - Miguel A de Pedro
- Centro de Biología Molecular "Severo Ochoa" - Consejo Superior de Investigaciones Científicas, Universidad Autónoma de MadridMadrid, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
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27
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Popp D, Loh ND, Zorgati H, Ghoshdastider U, Liow LT, Ivanova MI, Larsson M, DePonte DP, Bean R, Beyerlein KR, Gati C, Oberthuer D, Arnlund D, Brändén G, Berntsen P, Cascio D, Chavas LMG, Chen JPJ, Ding K, Fleckenstein H, Gumprecht L, Harimoorthy R, Mossou E, Sawaya MR, Brewster AS, Hattne J, Sauter NK, Seibert M, Seuring C, Stellato F, Tilp T, Eisenberg DS, Messerschmidt M, Williams GJ, Koglin JE, Makowski L, Millane RP, Forsyth T, Boutet S, White TA, Barty A, Chapman H, Chen SL, Liang M, Neutze R, Robinson RC. Flow-aligned, single-shot fiber diffraction using a femtosecond X-ray free-electron laser. Cytoskeleton (Hoboken) 2017; 74:472-481. [PMID: 28574190 DOI: 10.1002/cm.21378] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/25/2017] [Accepted: 05/29/2017] [Indexed: 01/26/2023]
Abstract
A major goal for X-ray free-electron laser (XFEL) based science is to elucidate structures of biological molecules without the need for crystals. Filament systems may provide some of the first single macromolecular structures elucidated by XFEL radiation, since they contain one-dimensional translational symmetry and thereby occupy the diffraction intensity region between the extremes of crystals and single molecules. Here, we demonstrate flow alignment of as few as 100 filaments (Escherichia coli pili, F-actin, and amyloid fibrils), which when intersected by femtosecond X-ray pulses result in diffraction patterns similar to those obtained from classical fiber diffraction studies. We also determine that F-actin can be flow-aligned to a disorientation of approximately 5 degrees. Using this XFEL-based technique, we determine that gelsolin amyloids are comprised of stacked β-strands running perpendicular to the filament axis, and that a range of order from fibrillar to crystalline is discernable for individual α-synuclein amyloids.
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Affiliation(s)
- David Popp
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore
| | - N Duane Loh
- Department of Physics, National University of Singapore, 117557, Singapore.,Centre for BioImaging Sciences, National University of Singapore, 117546, Singapore
| | - Habiba Zorgati
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore.,Department of Biochemistry, National University of Singapore, 117597, Singapore
| | - Umesh Ghoshdastider
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore
| | - Lu Ting Liow
- Department of Medicine, National University of Singapore, 119074, Singapore
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, 109 Zina Pitcher Pl, Ann Arbor, Michigan, 48109
| | - Mårten Larsson
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore
| | - Daniel P DePonte
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025
| | - Richard Bean
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Kenneth R Beyerlein
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Cornelius Gati
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Dominik Oberthuer
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany.,Institute of Biochemistry and Molecular Biology, University of Hamburg, Hamburg, 22607, Germany
| | - David Arnlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Gisela Brändén
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Peter Berntsen
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Duilio Cascio
- Howard Hughes Medical Institute, University of California, Los Angeles, California, 90095
| | - Leonard M G Chavas
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Joe P J Chen
- Department of Electrical and Computer Engineering, Computational Imaging Group, University of Canterbury, Christchurch, New Zealand
| | - Ke Ding
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore
| | - Holger Fleckenstein
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Lars Gumprecht
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Rajiv Harimoorthy
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Estelle Mossou
- Institut Laue-Langevin, Grenoble, 38000, France.,EPSAM/ISTM, Keele University, Staffordshire, ST5 5BG, United Kingdom
| | - Michael R Sawaya
- Howard Hughes Medical Institute, University of California, Los Angeles, California, 90095
| | - Aaron S Brewster
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720
| | - Johan Hattne
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720
| | - Nicholas K Sauter
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720
| | - Marvin Seibert
- Department of Cell and Molecular Biology, Molecular Biophysics, Uppsala University, Uppsala, 751 24, Sweden
| | - Carolin Seuring
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Francesco Stellato
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Thomas Tilp
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - David S Eisenberg
- Howard Hughes Medical Institute, University of California, Los Angeles, California, 90095
| | - Marc Messerschmidt
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025
| | - Garth J Williams
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025
| | - Jason E Koglin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025
| | - Lee Makowski
- Department of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, Massachusetts, 02115
| | - Rick P Millane
- Department of Electrical and Computer Engineering, Computational Imaging Group, University of Canterbury, Christchurch, New Zealand
| | - Trevor Forsyth
- Institut Laue-Langevin, Grenoble, 38000, France.,EPSAM/ISTM, Keele University, Staffordshire, ST5 5BG, United Kingdom
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025
| | - Thomas A White
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Anton Barty
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Henry Chapman
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany.,Department of Physics, University of Hamburg, Luruper Chaussee 149, Hamburg, 22607, Germany
| | - Swaine L Chen
- Department of Medicine, National University of Singapore, 119074, Singapore.,Genome Institute of Singapore, Biopolis, A*STAR (Agency for Science, Technology and Research), 138672, Singapore
| | - Mengning Liang
- Center for Free Electron Laser Science, DESY, Notkestrasse 85, Hamburg, 22607, Germany
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Robert C Robinson
- Institute of Molecular and Cell Biology, Biopolis, A*STAR (Agency for Science, Technology and Research), 138673, Singapore.,Department of Biochemistry, National University of Singapore, 117597, Singapore.,Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan
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28
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Jiang S, Ghoshdastider U, Narita A, Popp D, Robinson RC. Structural complexity of filaments formed from the actin and tubulin folds. Commun Integr Biol 2016; 9:e1242538. [PMID: 28042378 PMCID: PMC5193048 DOI: 10.1080/19420889.2016.1242538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 11/09/2022] Open
Abstract
From yeast to man, an evolutionary distance of 1.3 billion years, the F-actin filament structure has been conserved largely in line with the 94% sequence identity. The situation is entirely different in bacteria. In comparison to eukaryotic actins, the bacterial actin-like proteins (ALPs) show medium to low levels of sequence identity. This is extreme in the case of the ParM family of proteins, which often display less than 20% identity. ParMs are plasmid segregation proteins that form the polymerizing motors that propel pairs of plasmids to the extremities of a cell prior to cell division, ensuring faithful inheritance of the plasmid. Recently, exotic ParM filament structures have been elucidated that show ParM filament geometries are not limited to the standard polar pair of strands typified by actin. Four-stranded non-polar ParM filaments existing as open or closed nanotubules are found in Clostridium tetani and Bacillus thuringiensis, respectively. These diverse architectures indicate that the actin fold is capable of forming a large variety of filament morphologies, and that the conception of the “actin” filament has been heavily influenced by its conservation in eukaryotes. Here, we review the history of the structure determination of the eukaryotic actin filament to give a sense of context for the discovery of the new ParM filament structures. We describe the novel ParM geometries and predict that even more complex actin-like filaments may exist in bacteria. Finally, we compare the architectures of filaments arising from the actin and tubulin folds and conclude that the basic units possess similar properties that can each form a range of structures. Thus, the use of the actin fold in microfilaments and the tubulin fold for microtubules likely arose from a wider range of filament possibilities, but became entrenched as those architectures in early eukaryotes.
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Affiliation(s)
- Shimin Jiang
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Umesh Ghoshdastider
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Akihiro Narita
- Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences , Furo-cho , Chikusa-ku, Nagoya, Japan
| | - David Popp
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Robert C Robinson
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research), Biopolis, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore; Lee Kong Chan School of Medicine, Singapore
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29
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Toro-Nahuelpan M, Müller FD, Klumpp S, Plitzko JM, Bramkamp M, Schüler D. Segregation of prokaryotic magnetosomes organelles is driven by treadmilling of a dynamic actin-like MamK filament. BMC Biol 2016; 14:88. [PMID: 27733152 PMCID: PMC5059902 DOI: 10.1186/s12915-016-0290-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The navigation of magnetotactic bacteria relies on specific intracellular organelles, the magnetosomes, which are membrane-enclosed crystals of magnetite aligned into a linear chain. The magnetosome chain acts as a cellular compass, aligning the cells in the geomagnetic field in order to search for suitable environmental conditions in chemically stratified water columns and sediments. During cytokinesis, magnetosome chains have to be properly positioned, cleaved and separated in order to be evenly passed into daughter cells. In Magnetospirillum gryphiswaldense, the assembly of the magnetosome chain is controlled by the actin-like MamK, which polymerizes into cytoskeletal filaments that are connected to magnetosomes through the acidic MamJ protein. MamK filaments were speculated to recruit the magnetosome chain to cellular division sites, thus ensuring equal organelle inheritance. However, the underlying mechanism of magnetic organelle segregation has remained largely unknown. RESULTS Here, we performed in vivo time-lapse fluorescence imaging to directly track the intracellular movement and dynamics of magnetosome chains as well as photokinetic and ultrastructural analyses of the actin-like cytoskeletal MamK filament. We show that magnetosome chains undergo rapid intracellular repositioning from the new poles towards midcell into the newborn daughter cells, and the driving force for magnetosomes movement is likely provided by the pole-to-midcell treadmilling growth of MamK filaments. We further discovered that splitting and equipartitioning of magnetosome chains occurs with unexpectedly high accuracy, which depends directly on the dynamics of MamK filaments. CONCLUSION We propose a novel mechanism for prokaryotic organelle segregation that, similar to the type-II bacterial partitioning system of plasmids, relies on the action of cytomotive actin-like filaments together with specific connectors, which transport the magnetosome cargo in a fashion reminiscent of eukaryotic actin-organelle transport and segregation mechanisms.
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Affiliation(s)
- Mauricio Toro-Nahuelpan
- Department of Microbiology, University of Bayreuth, 95447, Bayreuth, Germany.,Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Planegg-Martinsried, Germany
| | - Frank D Müller
- Department of Microbiology, University of Bayreuth, 95447, Bayreuth, Germany
| | - Stefan Klumpp
- Department Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.,Institute for Nonlinear Dynamics, Georg August University Göttingen, Göttingen, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Planegg-Martinsried, Germany
| | - Marc Bramkamp
- Department of Biology I, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Dirk Schüler
- Department of Microbiology, University of Bayreuth, 95447, Bayreuth, Germany.
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30
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Abstract
Organisms from all domains of life depend on filaments of the protein actin to provide structure and to support internal movements. Many eukaryotic cells use forces produced by actin polymerization for their motility, and myosin motor proteins use ATP hydrolysis to produce force on actin filaments. Actin polymerizes spontaneously, followed by hydrolysis of a bound adenosine triphosphate (ATP). Dissociation of the γ-phosphate prepares the polymer for disassembly. This review provides an overview of the properties of actin and shows how dozens of proteins control both the assembly and disassembly of actin filaments. These players catalyze nucleotide exchange on actin monomers, initiate polymerization, promote phosphate dissociation, cap the ends of polymers, cross-link filaments to each other and other cellular components, and sever filaments.
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31
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Din MO, Danino T, Prindle A, Skalak M, Selimkhanov J, Allen K, Julio E, Atolia E, Tsimring LS, Bhatia SN, Hasty J. Synchronized cycles of bacterial lysis for in vivo delivery. Nature 2016; 536:81-85. [PMID: 27437587 PMCID: PMC5048415 DOI: 10.1038/nature18930] [Citation(s) in RCA: 387] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 06/13/2016] [Indexed: 12/29/2022]
Abstract
The pervasive view of bacteria as strictly pathogenic has given way to an appreciation of the widespread prevalence of beneficial microbes within the human body1–3. Given this milieu, it is perhaps inevitable that some bacteria would evolve to preferentially grow in environments that harbor disease and thus provide a natural platform for the development of engineered therapies4–6. Such therapies could benefit from bacteria that are programmed to limit bacterial growth while continually producing and releasing cytotoxic agents in situ7–10. Here, we engineer a clinically relevant bacterium to lyse synchronously at a threshold population density and to release genetically encoded cargo. Following quorum lysis, a small number of surviving bacteria reseed the growing population, thus leading to pulsatile delivery cycles. We use microfluidic devices to characterize the engineered lysis strain and we demonstrate its potential as a drug delivery platform via co-culture with human cancer cells in vitro. As a proof of principle, we track the bacterial population dynamics in ectopic syngeneic colorectal tumors in mice. The lysis strain exhibits pulsatile population dynamics in vivo, with mean bacterial luminescence that remained two orders of magnitude lower than an unmodified strain. Finally, guided by previous findings that certain bacteria can enhance the efficacy of standard therapies11, we orally administer the lysis strain, alone or in combination with a clinical chemotherapeutic, to a syngeneic transplantation model of hepatic colorectal metastases. We find that the combination of both circuit-engineered bacteria and chemotherapy leads to a notable reduction of tumor activity along with a marked survival benefit over either therapy alone. Our approach establishes a methodology for leveraging the tools of synthetic biology to exploit the natural propensity for certain bacteria to colonize disease sites.
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Affiliation(s)
- M Omar Din
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Tal Danino
- Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Arthur Prindle
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Matt Skalak
- Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Jangir Selimkhanov
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Kaitlin Allen
- Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Ellixis Julio
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Eta Atolia
- Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA
| | - Lev S Tsimring
- BioCircuits Institute, University of California, San Diego, La Jolla, California, USA
| | - Sangeeta N Bhatia
- Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA.,Broad Institute of Harvard and MIT, Cambridge, MA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA.,Electrical Engineering and Computer Science and David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA.,Howard Hughes Medical Institute, Chevy Chase, MD
| | - Jeff Hasty
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA.,BioCircuits Institute, University of California, San Diego, La Jolla, California, USA.,Molecular Biology Section, Division of Biological Science, University of California, San Diego, La Jolla, CA 92093, USA
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32
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Dynamic Filament Formation by a Divergent Bacterial Actin-Like ParM Protein. PLoS One 2016; 11:e0156944. [PMID: 27310470 PMCID: PMC4911067 DOI: 10.1371/journal.pone.0156944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 05/23/2016] [Indexed: 01/24/2023] Open
Abstract
Actin-like proteins (Alps) are a diverse family of proteins whose genes are abundant in the chromosomes and mobile genetic elements of many bacteria. The low-copy-number staphylococcal multiresistance plasmid pSK41 encodes ParM, an Alp involved in efficient plasmid partitioning. pSK41 ParM has previously been shown to form filaments in vitro that are structurally dissimilar to those formed by other bacterial Alps. The mechanistic implications of these differences are not known. In order to gain insights into the properties and behavior of the pSK41 ParM Alp in vivo, we reconstituted the parMRC system in the ectopic rod-shaped host, E. coli, which is larger and more genetically amenable than the native host, Staphylococcus aureus. Fluorescence microscopy showed a functional fusion protein, ParM-YFP, formed straight filaments in vivo when expressed in isolation. Strikingly, however, in the presence of ParR and parC, ParM-YFP adopted a dramatically different structure, instead forming axial curved filaments. Time-lapse imaging and selective photobleaching experiments revealed that, in the presence of all components of the parMRC system, ParM-YFP filaments were dynamic in nature. Finally, molecular dissection of the parMRC operon revealed that all components of the system are essential for the generation of dynamic filaments.
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33
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Danino T, Prindle A, Kwong GA, Skalak M, Li H, Allen K, Hasty J, Bhatia SN. Programmable probiotics for detection of cancer in urine. Sci Transl Med 2016; 7:289ra84. [PMID: 26019220 DOI: 10.1126/scitranslmed.aaa3519] [Citation(s) in RCA: 238] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rapid advances in the forward engineering of genetic circuitry in living cells has positioned synthetic biology as a potential means to solve numerous biomedical problems, including disease diagnosis and therapy. One challenge in exploiting synthetic biology for translational applications is to engineer microbes that are well tolerated by patients and seamlessly integrate with existing clinical methods. We use the safe and widely used probiotic Escherichia coli Nissle 1917 to develop an orally administered diagnostic that can noninvasively indicate the presence of liver metastasis by producing easily detectable signals in urine. Our microbial diagnostic generated a high-contrast urine signal through selective expansion in liver metastases (10(6)-fold enrichment) and high expression of a lacZ reporter maintained by engineering a stable plasmid system. The lacZ reporter cleaves a substrate to produce a small molecule that can be detected in urine. E. coli Nissle 1917 robustly colonized tumor tissue in rodent models of liver metastasis after oral delivery but did not colonize healthy organs or fibrotic liver tissue. We saw no deleterious health effects on the mice for more than 12 months after oral delivery. Our results demonstrate that probiotics can be programmed to safely and selectively deliver synthetic gene circuits to diseased tissue microenvironments in vivo.
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Affiliation(s)
- Tal Danino
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Arthur Prindle
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gabriel A Kwong
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Matthew Skalak
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Howard Li
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaitlin Allen
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Jeff Hasty
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA. BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA. Molecular Biology Section, Division of Biological Science, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sangeeta N Bhatia
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA. Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA. Electrical Engineering and Computer Science and David H. Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA 02139, USA. Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Deng A, Lin W, Shi N, Wu J, Sun Z, Sun Q, Bai H, Pan Y, Wen T. In vitro assembly of the bacterial actin protein MamK from ' Candidatus Magnetobacterium casensis' in the phylum Nitrospirae. Protein Cell 2016; 7:267-280. [PMID: 26960409 PMCID: PMC4818849 DOI: 10.1007/s13238-016-0253-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 02/07/2016] [Indexed: 10/29/2022] Open
Abstract
Magnetotactic bacteria (MTB), a group of phylogenetically diverse organisms that use their unique intracellular magnetosome organelles to swim along the Earth's magnetic field, play important roles in the biogeochemical cycles of iron and sulfur. Previous studies have revealed that the bacterial actin protein MamK plays essential roles in the linear arrangement of magnetosomes in MTB cells belonging to the Proteobacteria phylum. However, the molecular mechanisms of multiple-magnetosome-chain arrangements in MTB remain largely unknown. Here, we report that the MamK filaments from the uncultivated 'Candidatus Magnetobacterium casensis' (Mcas) within the phylum Nitrospirae polymerized in the presence of ATP alone and were stable without obvious ATP hydrolysis-mediated disassembly. MamK in Mcas can convert NTP to NDP and NDP to NMP, showing the highest preference to ATP. Unlike its Magnetospirillum counterparts, which form a single magnetosome chain, or other bacterial actins such as MreB and ParM, the polymerized MamK from Mcas is independent of metal ions and nucleotides except for ATP, and is assembled into well-ordered filamentous bundles consisted of multiple filaments. Our results suggest a dynamically stable assembly of MamK from the uncultivated Nitrospirae MTB that synthesizes multiple magnetosome chains per cell. These findings further improve the current knowledge of biomineralization and organelle biogenesis in prokaryotic systems.
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Affiliation(s)
- Aihua Deng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wei Lin
- Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Nana Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jie Wu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhaopeng Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qinyun Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hua Bai
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yongxin Pan
- Biogeomagnetism Group, Paleomagnetism and Geochronology Laboratory, Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Tingyi Wen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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35
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Abstract
There is a growing need to enhance our capabilities in medical and environmental diagnostics. Synthetic biologists have begun to focus their biomolecular engineering approaches toward this goal, offering promising results that could lead to the development of new classes of inexpensive, rapidly deployable diagnostics. Many conventional diagnostics rely on antibody-based platforms that, although exquisitely sensitive, are slow and costly to generate and cannot readily confront rapidly emerging pathogens or be applied to orphan diseases. Synthetic biology, with its rational and short design-to-production cycles, has the potential to overcome many of these limitations. Synthetic biology devices, such as engineered gene circuits, bring new capabilities to molecular diagnostics, expanding the molecular detection palette, creating dynamic sensors, and untethering reactions from laboratory equipment. The field is also beginning to move toward in vivo diagnostics, which could provide near real-time surveillance of multiple pathological conditions. Here, we describe current efforts in synthetic biology, focusing on the translation of promising technologies into pragmatic diagnostic tools and platforms.
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36
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Abstract
The stable maintenance of low-copy-number plasmids in bacteria is actively driven by partition mechanisms that are responsible for the positioning of plasmids inside the cell. Partition systems are ubiquitous in the microbial world and are encoded by many bacterial chromosomes as well as plasmids. These systems, although different in sequence and mechanism, typically consist of two proteins and a DNA partition site, or prokaryotic centromere, on the plasmid or chromosome. One protein binds site-specifically to the centromere to form a partition complex, and the other protein uses the energy of nucleotide binding and hydrolysis to transport the plasmid, via interactions with this partition complex inside the cell. For plasmids, this minimal cassette is sufficient to direct proper segregation in bacterial cells. There has been significant progress in the last several years in our understanding of partition mechanisms. Two general areas that have developed are (i) the structural biology of partition proteins and their interactions with DNA and (ii) the action and dynamics of the partition ATPases that drive the process. In addition, systems that use tubulin-like GTPases to partition plasmids have recently been identified. In this chapter, we concentrate on these recent developments and the molecular details of plasmid partition mechanisms.
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37
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Hepler PK. The Cytoskeleton and Its Regulation by Calcium and Protons. PLANT PHYSIOLOGY 2016; 170:3-22. [PMID: 26722019 PMCID: PMC4704593 DOI: 10.1104/pp.15.01506] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/28/2015] [Indexed: 05/18/2023]
Abstract
Calcium and protons exert control over the formation and activity of the cytoskeleton, usually by modulating an associated motor protein or one that affects the structural organization of the polymer.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
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38
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39
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Kim MK, Kim JH, Kim JS, Kang SO. Structure of the 34 kDa F-actin-bundling protein ABP34 from Dictyostelium discoideum. ACTA ACUST UNITED AC 2015; 71:1835-49. [PMID: 26327373 DOI: 10.1107/s139900471501264x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/30/2015] [Indexed: 11/11/2022]
Abstract
The crystal structure of the 34 kDa F-actin-bundling protein ABP34 from Dictyostelium discoideum was solved by Ca(2+)/S-SAD phasing and refined at 1.89 Å resolution. ABP34 is a calcium-regulated actin-binding protein that cross-links actin filaments into bundles. Its in vitro F-actin-binding and F-actin-bundling activities were confirmed by a co-sedimentation assay and transmission electron microscopy. The co-localization of ABP34 with actin in cells was also verified. ABP34 adopts a two-domain structure with an EF-hand-containing N-domain and an actin-binding C-domain, but has no reported overall structural homologues. The EF-hand is occupied by a calcium ion with a pentagonal bipyramidal coordination as in the canonical EF-hand. The C-domain structure resembles a three-helical bundle and superposes well onto the rod-shaped helical structures of some cytoskeletal proteins. Residues 216-244 in the C-domain form part of the strongest actin-binding sites (193-254) and exhibit a conserved sequence with the actin-binding region of α-actinin and ABP120. Furthermore, the second helical region of the C-domain is kinked by a proline break, offering a convex surface towards the solvent area which is implicated in actin binding. The F-actin-binding model suggests that ABP34 binds to the side of the actin filament and residues 216-244 fit into a pocket between actin subdomains -1 and -2 through hydrophobic interactions. These studies provide insights into the calcium coordination in the EF-hand and F-actin-binding site in the C-domain of ABP34, which are associated through interdomain interactions.
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Affiliation(s)
- Min-Kyu Kim
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Ji-Hye Kim
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Ji-Sun Kim
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sa-Ouk Kang
- Laboratory of Biophysics, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea
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Abstract
The prokaryotic origins of the actin cytoskeleton have been firmly established, but it has become clear that the bacterial actins form a wide variety of different filaments, different both from each other and from eukaryotic F-actin. We have used electron cryomicroscopy (cryo-EM) to examine the filaments formed by the protein crenactin (a crenarchaeal actin) from Pyrobaculum calidifontis, an organism that grows optimally at 90 °C. Although this protein only has ∼ 20% sequence identity with eukaryotic actin, phylogenetic analyses have placed it much closer to eukaryotic actin than any of the bacterial homologs. It has been assumed that the crenactin filament is double-stranded, like F-actin, in part because it would be hard to imagine how a single-stranded filament would be stable at such high temperatures. We show that not only is the crenactin filament single-stranded, but that it is remarkably similar to each of the two strands in F-actin. A large insertion in the crenactin sequence would prevent the formation of an F-actin-like double-stranded filament. Further, analysis of two existing crystal structures reveals six different subunit-subunit interfaces that are filament-like, but each is different from the others in terms of significant rotations. This variability in the subunit-subunit interface, seen at atomic resolution in crystals, can explain the large variability in the crenactin filaments observed by cryo-EM and helps to explain the variability in twist that has been observed for eukaryotic actin filaments.
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Eun YJ, Kapoor M, Hussain S, Garner EC. Bacterial Filament Systems: Toward Understanding Their Emergent Behavior and Cellular Functions. J Biol Chem 2015; 290:17181-9. [PMID: 25957405 DOI: 10.1074/jbc.r115.637876] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacteria use homologs of eukaryotic cytoskeletal filaments to conduct many different tasks, controlling cell shape, division, and DNA segregation. These filaments, combined with factors that regulate their polymerization, create emergent self-organizing machines. Here, we summarize the current understanding of the assembly of these polymers and their spatial regulation by accessory factors, framing them in the context of being dynamical systems. We highlight how comparing the in vivo dynamics of the filaments with those measured in vitro has provided insight into the regulation, emergent behavior, and cellular functions of these polymeric systems.
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Affiliation(s)
- Ye-Jin Eun
- From the Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Mrinal Kapoor
- From the Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Saman Hussain
- From the Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Ethan C Garner
- From the Molecular and Cellular Biology Department and Faculty of Arts and Sciences (FAS) Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
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Donovan C, Heyer A, Pfeifer E, Polen T, Wittmann A, Krämer R, Frunzke J, Bramkamp M. A prophage-encoded actin-like protein required for efficient viral DNA replication in bacteria. Nucleic Acids Res 2015; 43:5002-16. [PMID: 25916847 PMCID: PMC4446434 DOI: 10.1093/nar/gkv374] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/09/2015] [Indexed: 12/31/2022] Open
Abstract
In host cells, viral replication is localized at specific subcellular sites. Viruses that infect eukaryotic and prokaryotic cells often use host-derived cytoskeletal structures, such as the actin skeleton, for intracellular positioning. Here, we describe that a prophage, CGP3, integrated into the genome of Corynebacterium glutamicum encodes an actin-like protein, AlpC. Biochemical characterization confirms that AlpC is a bona fide actin-like protein and cell biological analysis shows that AlpC forms filamentous structures upon prophage induction. The co-transcribed adaptor protein, AlpA, binds to a consensus sequence in the upstream promoter region of the alpAC operon and also interacts with AlpC, thus connecting circular phage DNA to the actin-like filaments. Transcriptome analysis revealed that alpA and alpC are among the early induced genes upon excision of the CGP3 prophage. Furthermore, qPCR analysis of mutant strains revealed that both AlpA and AlpC are required for efficient phage replication. Altogether, these data emphasize that AlpAC are crucial for the spatio-temporal organization of efficient viral replication. This is remarkably similar to actin-assisted membrane localization of eukaryotic viruses that use the actin cytoskeleton to concentrate virus particles at the egress sites and provides a link of evolutionary conserved interactions between intracellular virus transport and actin.
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Affiliation(s)
- Catriona Donovan
- Department of Biology I, Ludwig-Maximilians-University Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany Institute for Biochemistry, University of Cologne, Zülpicherstr. 47, 50674 Cologne, Germany
| | - Antonia Heyer
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Eugen Pfeifer
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Tino Polen
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Anja Wittmann
- Institute for Biochemistry, University of Cologne, Zülpicherstr. 47, 50674 Cologne, Germany
| | - Reinhard Krämer
- Institute for Biochemistry, University of Cologne, Zülpicherstr. 47, 50674 Cologne, Germany
| | - Julia Frunzke
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Marc Bramkamp
- Department of Biology I, Ludwig-Maximilians-University Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany Institute for Biochemistry, University of Cologne, Zülpicherstr. 47, 50674 Cologne, Germany
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43
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Galkin VE, Orlova A, Vos MR, Schröder GF, Egelman EH. Near-atomic resolution for one state of F-actin. Structure 2014; 23:173-182. [PMID: 25533486 DOI: 10.1016/j.str.2014.11.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 11/03/2014] [Accepted: 11/14/2014] [Indexed: 01/15/2023]
Abstract
Actin functions as a helical polymer, F-actin, but attempts to build an atomic model for this filament have been hampered by the fact that the filament cannot be crystallized and by structural heterogeneity. We have used a direct electron detector, cryo-electron microscopy, and the forces imposed on actin filaments in thin films to reconstruct one state of the filament at 4.7 Å resolution, which allows for building a reliable pseudo-atomic model of F-actin. We also report a different state of the filament where actin protomers adopt a conformation observed in the crystal structure of the G-actin-profilin complex with an open ATP-binding cleft. Comparison of the two structural states provides insights into ATP-hydrolysis and filament dynamics. The atomic model provides a framework for understanding why every buried residue in actin has been under intense selective pressure.
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Affiliation(s)
- Vitold E Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA.
| | - Albina Orlova
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Matthijn R Vos
- FEI Company, Nanoport Europe, 5651 GG Eindhoven, the Netherlands
| | - Gunnar F Schröder
- Institute of Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany; Physics Department, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA.
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Abstract
Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins.
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45
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Erb ML, Kraemer JA, Coker JKC, Chaikeeratisak V, Nonejuie P, Agard DA, Pogliano J. A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells. eLife 2014; 3. [PMID: 25429514 PMCID: PMC4244570 DOI: 10.7554/elife.03197] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 10/22/2014] [Indexed: 11/13/2022] Open
Abstract
Dynamic instability, polarity, and spatiotemporal organization are hallmarks of the microtubule cytoskeleton that allow formation of complex structures such as the eukaryotic spindle. No similar structure has been identified in prokaryotes. The bacteriophage-encoded tubulin PhuZ is required to position DNA at mid-cell, without which infectivity is compromised. Here, we show that PhuZ filaments, like microtubules, stochastically switch from growing in a distinctly polar manner to catastrophic depolymerization (dynamic instability) both in vitro and in vivo. One end of each PhuZ filament is stably anchored near the cell pole to form a spindle-like array that orients the growing ends toward the phage nucleoid so as to position it near mid-cell. Our results demonstrate how a bacteriophage can harness the properties of a tubulin-like cytoskeleton for efficient propagation. This represents the first identification of a prokaryotic tubulin with the dynamic instability of microtubules and the ability to form a simplified bipolar spindle.
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Affiliation(s)
- Marcella L Erb
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - James A Kraemer
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Joanna K C Coker
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Vorrapon Chaikeeratisak
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Poochit Nonejuie
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - David A Agard
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Joe Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, United States
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46
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Abstract
One of the most important discoveries in the field of microbiology in the last two decades is that bacterial cells have intricate subcellular organization. This understanding has emerged mainly from the depiction of spatial and temporal organization of proteins in specific domains within bacterial cells, e.g., midcell, cell poles, membrane and periplasm. Because translation of bacterial RNA molecules was considered to be strictly coupled to their synthesis, they were not thought to specifically localize to regions outside the nucleoid. However, the increasing interest in RNAs, including non-coding RNAs, encouraged researchers to explore the spatial and temporal localization of RNAs in bacteria. The recent technological improvements in the field of fluorescence microscopy allowed subcellular imaging of RNAs even in the tiny bacterial cells. It has been reported by several groups, including ours that transcripts may specifically localize in such cells. Here we review what is known about localization of RNA and of the pathways that determine RNA fate in bacteria, and discuss the possible cues and mechanisms underlying these distribution patterns.
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Affiliation(s)
- Avi-ad Avraam Buskila
- a Department of Microbiology and Molecular Genetics; IMRIC ; The Hebrew University Faculty of Medicine ; Israel
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47
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Ramachandran G, Singh PK, Luque-Ortega JR, Yuste L, Alfonso C, Rojo F, Wu LJ, Meijer WJJ. A complex genetic switch involving overlapping divergent promoters and DNA looping regulates expression of conjugation genes of a gram-positive plasmid. PLoS Genet 2014; 10:e1004733. [PMID: 25340403 PMCID: PMC4207663 DOI: 10.1371/journal.pgen.1004733] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 09/03/2014] [Indexed: 11/22/2022] Open
Abstract
Plasmid conjugation plays a significant role in the dissemination of antibiotic resistance and pathogenicity determinants. Understanding how conjugation is regulated is important to gain insights into these features. Little is known about regulation of conjugation systems present on plasmids from Gram-positive bacteria. pLS20 is a native conjugative plasmid from the Gram-positive bacterium Bacillus subtilis. Recently the key players that repress and activate pLS20 conjugation have been identified. Here we studied in detail the molecular mechanism regulating the pLS20 conjugation genes using both in vivo and in vitro approaches. Our results show that conjugation is subject to the control of a complex genetic switch where at least three levels of regulation are integrated. The first of the three layers involves overlapping divergent promoters of different strengths regulating expression of the conjugation genes and the key transcriptional regulator RcoLS20. The second layer involves a triple function of RcoLS20 being a repressor of the main conjugation promoter and an activator and repressor of its own promoter at low and high concentrations, respectively. The third level of regulation concerns formation of a DNA loop mediated by simultaneous binding of tetrameric RcoLS20 to two operators, one of which overlaps with the divergent promoters. The combination of these three layers of regulation in the same switch allows the main conjugation promoter to be tightly repressed during conditions unfavorable to conjugation while maintaining the sensitivity to accurately switch on the conjugation genes when appropriate conditions occur. The implications of the regulatory switch and comparison with other genetic switches involving DNA looping are discussed. Plasmids are extrachromosomal, autonomously replicating units that are harbored by many bacteria. Many plasmids encode transfer function allowing them to be transferred into plasmid-free bacteria by a process named conjugation. Since many of them also carry antibiotic resistance genes, plasmid-mediated conjugation is a major mechanism in the dissemination of antibiotic resistance. In depth knowledge on the regulation of conjugation genes is a prerequisite to design measures interfering with the spread of antibiotic resistance. pLS20 is a conjugative plasmid of the soil bacterium Bacillus subtilis, which is also a gut commensal in animals and humans. Here we describe in detail the molecular mechanism by which the key transcriptional regulator tightly represses the conjugation genes during conditions unfavorable to conjugation without compromising the ability to switch on accurately the conjugation genes when appropriate. We found that conjugation is subject to the control of a unique genetic switch where at least three levels of regulation are integrated. The first level involves overlapping divergent promoters of different strengths. The second layer involves a triple function of the transcriptional regulator. And the third level of regulation concerns formation of a DNA loop mediated by the transcriptional regulator.
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Affiliation(s)
- Gayetri Ramachandran
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Universidad Autónoma, Canto Blanco, Madrid, Spain
| | - Praveen K. Singh
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Universidad Autónoma, Canto Blanco, Madrid, Spain
| | | | - Luis Yuste
- Centro Nacional de Biotecnología (CSIC), Canto Blanco, Madrid, Spain
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
| | - Fernando Rojo
- Centro Nacional de Biotecnología (CSIC), Canto Blanco, Madrid, Spain
| | - Ling J. Wu
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Wilfried J. J. Meijer
- Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Instituto de Biología Molecular “Eladio Viñuela” (CSIC), Universidad Autónoma, Canto Blanco, Madrid, Spain
- * E-mail:
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Jékely G. Origin and evolution of the self-organizing cytoskeleton in the network of eukaryotic organelles. Cold Spring Harb Perspect Biol 2014; 6:a016030. [PMID: 25183829 DOI: 10.1101/cshperspect.a016030] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The eukaryotic cytoskeleton evolved from prokaryotic cytomotive filaments. Prokaryotic filament systems show bewildering structural and dynamic complexity and, in many aspects, prefigure the self-organizing properties of the eukaryotic cytoskeleton. Here, the dynamic properties of the prokaryotic and eukaryotic cytoskeleton are compared, and how these relate to function and evolution of organellar networks is discussed. The evolution of new aspects of filament dynamics in eukaryotes, including severing and branching, and the advent of molecular motors converted the eukaryotic cytoskeleton into a self-organizing "active gel," the dynamics of which can only be described with computational models. Advances in modeling and comparative genomics hold promise of a better understanding of the evolution of the self-organizing cytoskeleton in early eukaryotes, and its role in the evolution of novel eukaryotic functions, such as amoeboid motility, mitosis, and ciliary swimming.
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Affiliation(s)
- Gáspár Jékely
- Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany
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49
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Interplay between two bacterial actin homologs, MamK and MamK-Like, is required for the alignment of magnetosome organelles in Magnetospirillum magneticum AMB-1. J Bacteriol 2014; 196:3111-21. [PMID: 24957623 DOI: 10.1128/jb.01674-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many bacterial species contain multiple actin-like proteins tasked with the execution of crucial cell biological functions. MamK, an actin-like protein found in magnetotactic bacteria, is important in organizing magnetosome organelles into chains that are used for navigation along geomagnetic fields. MamK and numerous other magnetosome formation factors are encoded by a genetic island termed the magnetosome island. Unlike most magnetotactic bacteria, Magnetospirillum magneticum AMB-1 (AMB-1) contains a second island of magnetosome-related genes that was named the magnetosome islet. A homologous copy of mamK, mamK-like, resides within this islet and encodes a protein capable of filament formation in vitro. Previous work had shown that mamK-like is expressed in vivo, but its function, if any, had remained unknown. Though MamK-like is highly similar to MamK, it contains a mutation that in MamK and other actins blocks ATPase activity in vitro and filament dynamics in vivo. Here, using genetic analysis, we demonstrate that mamK-like has an in vivo role in assisting organelle alignment. In addition, MamK-like forms filaments in vivo in a manner that is dependent on the presence of MamK and the two proteins interact in a yeast two-hybrid assay. Surprisingly, despite the ATPase active-site mutation, MamK-like is capable of ATP hydrolysis in vitro and promotes MamK filament turnover in vivo. Taken together, these experiments suggest that direct interactions between MamK and MamK-like contribute to magnetosome alignment in AMB-1.
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50
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Ku C, Lo WS, Kuo CH. Molecular evolution of the actin-like MreB protein gene family in wall-less bacteria. Biochem Biophys Res Commun 2014; 446:927-32. [DOI: 10.1016/j.bbrc.2014.03.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 01/01/2023]
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