1
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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: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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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2
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Ithurbide S, Gribaldo S, Albers SV, Pende N. Spotlight on FtsZ-based cell division in Archaea. Trends Microbiol 2022; 30:665-678. [PMID: 35246355 DOI: 10.1016/j.tim.2022.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 12/15/2022]
Abstract
Compared with the extensive knowledge on cell division in model eukaryotes and bacteria, little is known about how archaea divide. Interestingly, both endosomal sorting complex required for transport (ESCRT)-based and FtsZ-based cell division systems are found in members of the Archaea. In the past couple of years, several studies have started to shed light on FtsZ-based cell division processes in members of the Euryarchaeota. In this review we highlight recent findings in this emerging field of research. We present current knowledge of the cell division machinery of halophiles which relies on two FtsZ proteins, and we compare it with that of methanobacteria, which relies on only one FtsZ. Finally, we discuss how these differences relate to the distinct cell envelopes of these two archaeal model systems.
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Affiliation(s)
- Solenne Ithurbide
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Simonetta Gribaldo
- Evolutionary Biology of the Microbial Cell Unit, CNRS UMR2001, Department of Microbiology, Institut Pasteur, Paris, France.
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.
| | - Nika Pende
- Evolutionary Biology of the Microbial Cell Unit, CNRS UMR2001, Department of Microbiology, Institut Pasteur, Paris, France
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3
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Dersch S, Reimold C, Stoll J, Breddermann H, Heimerl T, Defeu Soufo HJ, Graumann PL. Polymerization of Bacillus subtilis MreB on a lipid membrane reveals lateral co-polymerization of MreB paralogs and strong effects of cations on filament formation. BMC Mol Cell Biol 2020; 21:76. [PMID: 33148162 PMCID: PMC7641798 DOI: 10.1186/s12860-020-00319-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/18/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND MreB is a bacterial ortholog of actin and forms mobile filaments underneath the cell membrane, perpendicular to the long axis of the cell, which play a crucial role for cell shape maintenance. We wished to visualize Bacillus subtilis MreB in vitro and therefore established a protocol to obtain monomeric protein, which could be polymerized on a planar membrane system, or associated with large membrane vesicles. RESULTS Using a planar membrane system and electron microscopy, we show that Bacillus subtilis MreB forms bundles of filaments, which can branch and fuse, with an average width of 70 nm. Fluorescence microscopy of non-polymerized YFP-MreB, CFP-Mbl and mCherry-MreBH proteins showed uniform binding to the membrane, suggesting that 2D diffusion along the membrane could facilitate filament formation. After addition of divalent magnesium and calcium ions, all three proteins formed highly disordered sheets of filaments that could split up or merge, such that at high protein concentration, MreB and its paralogs generated a network of filaments extending away from the membrane. Filament formation was positively affected by divalent ions and negatively by monovalent ions. YFP-MreB or CFP-Mbl also formed filaments between two adjacent membranes, which frequently has a curved appearance. New MreB, Mbl or MreBH monomers could add to the lateral side of preexisting filaments, and MreB paralogs co-polymerized, indicating direct lateral interaction between MreB paralogs. CONCLUSIONS Our data show that B. subtilis MreB paralogs do not easily form ordered filaments in vitro, possibly due to extensive lateral contacts, but can co-polymerise. Monomeric MreB, Mbl and MreBH uniformly bind to a membrane, and form irregular and frequently split up filamentous structures, facilitated by the addition of divalent ions, and counteracted by monovalent ions, suggesting that intracellular potassium levels may be one important factor to counteract extensive filament formation and filament splitting in vivo.
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Affiliation(s)
- Simon Dersch
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Christian Reimold
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Joshua Stoll
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany
| | | | - Thomas Heimerl
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany.,Fachbereich Biologie, Karl-von-Frisch-Straße 10, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Hervé Joel Defeu Soufo
- Department of Microsystems Engineering - IMTEK, University of Freiburg, 79110, Freiburg, Germany
| | - Peter L Graumann
- Centre for Synthetic Microbiology (SYNMIKRO) Hans-Meerwein Strasse 6, Philipps-Universität Marburg, 35032, Marburg, Germany. .,Fachbereich Chemie, Hans-Meerwein Strasse, Philipps-Universität Marburg, 35032, Marburg, Germany.
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4
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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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5
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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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6
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Pathway of Actin Folding Directed by the Eukaryotic Chaperonin TRiC. Cell 2018; 174:1507-1521.e16. [PMID: 30100183 DOI: 10.1016/j.cell.2018.07.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/20/2018] [Accepted: 07/03/2018] [Indexed: 12/22/2022]
Abstract
The hetero-oligomeric chaperonin of eukarya, TRiC, is required to fold the cytoskeletal protein actin. The simpler bacterial chaperonin system, GroEL/GroES, is unable to mediate actin folding. Here, we use spectroscopic and structural techniques to determine how TRiC promotes the conformational progression of actin to the native state. We find that actin fails to fold spontaneously even in the absence of aggregation but populates a kinetically trapped, conformationally dynamic state. Binding of this frustrated intermediate to TRiC specifies an extended topology of actin with native-like secondary structure. In contrast, GroEL stabilizes bound actin in an unfolded state. ATP binding to TRiC effects an asymmetric conformational change in the chaperonin ring. This step induces the partial release of actin, priming it for folding upon complete release into the chaperonin cavity, mediated by ATP hydrolysis. Our results reveal how the unique features of TRiC direct the folding pathway of an obligate eukaryotic substrate.
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7
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Bisson-Filho AW, Zheng J, Garner E. Archaeal imaging: leading the hunt for new discoveries. Mol Biol Cell 2018; 29:1675-1681. [PMID: 30001185 PMCID: PMC6080714 DOI: 10.1091/mbc.e17-10-0603] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/15/2018] [Accepted: 05/22/2018] [Indexed: 12/20/2022] Open
Abstract
Since the identification of the archaeal domain in the mid-1970s, we have collected a great deal of metagenomic, biochemical, and structural information from archaeal species. However, there is still little known about how archaeal cells organize their internal cellular components in space and time. In contrast, live-cell imaging has allowed bacterial and eukaryotic cell biologists to learn a lot about biological processes by observing the motions of cells, the dynamics of their internal organelles, and even the motions of single molecules. The explosion of knowledge gained via live-cell imaging in prokaryotes and eukaryotes has motivated an ever-improving set of imaging technologies that could allow analogous explorations into archaeal biology. Furthermore, previous studies of essential biological processes in prokaryotic and eukaryotic organisms give methodological roadmaps for the investigation of similar processes in archaea. In this perspective, we highlight a few fundamental cellular processes in archaea, reviewing our current state of understanding about each, and compare how imaging approaches helped to advance the study of similar processes in bacteria and eukaryotes.
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Affiliation(s)
| | | | - Ethan Garner
- Molecular and Cellular Biology, Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138
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8
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Lancaster CE, Ho CY, Hipolito VEB, Botelho RJ, Terebiznik MR. Phagocytosis: what's on the menu? 1. Biochem Cell Biol 2018; 97:21-29. [PMID: 29791809 DOI: 10.1139/bcb-2018-0008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phagocytosis is an evolutionarily conserved process. In Protozoa, phagocytosis fulfills a feeding mechanism, while in Metazoa, phagocytosis diversified to play multiple organismal roles, including immune defence, tissue homeostasis, and remodeling. Accordingly, phagocytes display a high level of plasticity in their capacity to recognize, engulf, and process targets that differ in composition and morphology. Here, we review how phagocytosis adapts to its multiple roles and discuss in particular the effect of target morphology in phagocytic uptake and phagosome maturation.
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Affiliation(s)
- Charlene E Lancaster
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada.,b Department of Cell and System Biology, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
| | - Cheuk Y Ho
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
| | - Victoria E B Hipolito
- c Molecular Science Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada.,d Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Roberto J Botelho
- c Molecular Science Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada.,d Department of Chemistry and Biology, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Mauricio R Terebiznik
- a Department of Biological Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada.,b Department of Cell and System Biology, University of Toronto at Scarborough, Toronto, ON M1C 1A4, Canada
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9
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Eme L, Spang A, Lombard J, Stairs CW, Ettema TJG. Archaea and the origin of eukaryotes. Nat Rev Microbiol 2017; 15:711-723. [DOI: 10.1038/nrmicro.2017.133] [Citation(s) in RCA: 279] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Abstract
Actin represents one of the most abundant and conserved eukaryotic proteins over time, and has an important role in many different cellular processes such as cell shape determination, motility, force generation, cytokinesis, amongst many others. Eukaryotic actin has been studied for decades and was for a long time considered a eukaryote-specific trait. However, in the early 2000s a bacterial actin homolog, MreB, was identified, characterized and found to have a cytoskeletal function and group within the superfamily of actin proteins. More recently, an actin cytoskeleton was also identified in archaea. The genome of the hyperthermophilic crenarchaeon Pyrobaculum calidifontis contains a five-gene cluster named Arcade encoding for an actin homolog, Crenactin, polymerizing into helical filaments spanning the whole length of the cell. Phylogenetic and structural studies place Crenactin closer to the eukaryotic actin than to the bacterial homologues. A significant difference, however, is that Crenactin can form single helical filaments in addition to filaments containing two intertwined proto filaments. The genome of the recently discovered Lokiarchaeota encodes several different actin homologues, termed Lokiactins, which are even more closely related to the eukaryotic actin than Crenactin. A primitive, dynamic actin-based cytoskeleton in archaea could have enabled the engulfment of the alphaproteobacterial progenitor of the mitochondria, a key-event in the evolution of eukaryotes.
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Affiliation(s)
- Ann-Christin Lindås
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius v. 20C, SE-106 91, Stockholm, Sweden.
| | - Karin Valegård
- Department of Cell and Molecular Biology/Molecular Biophysics, Uppsala University, Box 596, SE-751 24, Uppsala, Sweden
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology/Molecular Evolution, Uppsala University, Box 596, SE-751 24, Uppsala, Sweden
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11
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Abstract
A diverse set of protein polymers, structurally related to actin filaments contributes to the organization of bacterial cells as cytomotive or cytoskeletal filaments. This chapter describes actin homologs encoded by bacterial chromosomes. MamK filaments, unique to magnetotactic bacteria, help establishing magnetic biological compasses by interacting with magnetosomes. Magnetosomes are intracellular membrane invaginations containing biomineralized crystals of iron oxide that are positioned by MamK along the long-axis of the cell. FtsA is widespread across bacteria and it is one of the earliest components of the divisome to arrive at midcell, where it anchors the cell division machinery to the membrane. FtsA binds directly to FtsZ filaments and to the membrane through its C-terminus. FtsA shows altered domain architecture when compared to the canonical actin fold. FtsA's subdomain 1C replaces subdomain 1B of other members of the actin family and is located on the opposite side of the molecule. Nevertheless, when FtsA assembles into protofilaments, the protofilament structure is preserved, as subdomain 1C replaces subdomain IB of the following subunit in a canonical actin filament. MreB has an essential role in shape-maintenance of most rod-shaped bacteria. Unusually, MreB filaments assemble from two protofilaments in a flat and antiparallel arrangement. This non-polar architecture implies that both MreB filament ends are structurally identical. MreB filaments bind directly to membranes where they interact with both cytosolic and membrane proteins, thereby forming a key component of the elongasome. MreB filaments in cells are short and dynamic, moving around the long axis of rod-shaped cells, sensing curvature of the membrane and being implicated in peptidoglycan synthesis.
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Affiliation(s)
- Thierry Izoré
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Fusinita van den Ent
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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12
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Abstract
As discovered over the past 25 years, the cytoskeletons of bacteria and archaea are complex systems of proteins whose central components are dynamic cytomotive filaments. They perform roles in cell division, DNA partitioning, cell shape determination and the organisation of intracellular components. The protofilament structures and polymerisation activities of various actin-like, tubulin-like and ESCRT-like proteins of prokaryotes closely resemble their eukaryotic counterparts but show greater diversity. Their activities are modulated by a wide range of accessory proteins but these do not include homologues of the motor proteins that supplement filament dynamics to aid eukaryotic cell motility. Numerous other filamentous proteins, some related to eukaryotic IF-proteins/lamins and dynamins etc, seem to perform structural roles similar to those in eukaryotes.
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Affiliation(s)
- Linda A Amos
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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13
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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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14
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Koonin EV. Origin of eukaryotes from within archaea, archaeal eukaryome and bursts of gene gain: eukaryogenesis just made easier? Philos Trans R Soc Lond B Biol Sci 2016; 370:20140333. [PMID: 26323764 PMCID: PMC4571572 DOI: 10.1098/rstb.2014.0333] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The origin of eukaryotes is a fundamental, forbidding evolutionary puzzle. Comparative genomic analysis clearly shows that the last eukaryotic common ancestor (LECA) possessed most of the signature complex features of modern eukaryotic cells, in particular the mitochondria, the endomembrane system including the nucleus, an advanced cytoskeleton and the ubiquitin network. Numerous duplications of ancestral genes, e.g. DNA polymerases, RNA polymerases and proteasome subunits, also can be traced back to the LECA. Thus, the LECA was not a primitive organism and its emergence must have resulted from extensive evolution towards cellular complexity. However, the scenario of eukaryogenesis, and in particular the relationship between endosymbiosis and the origin of eukaryotes, is far from being clear. Four recent developments provide new clues to the likely routes of eukaryogenesis. First, evolutionary reconstructions suggest complex ancestors for most of the major groups of archaea, with the subsequent evolution dominated by gene loss. Second, homologues of signature eukaryotic proteins, such as actin and tubulin that form the core of the cytoskeleton or the ubiquitin system, have been detected in diverse archaea. The discovery of this ‘dispersed eukaryome’ implies that the archaeal ancestor of eukaryotes was a complex cell that might have been capable of a primitive form of phagocytosis and thus conducive to endosymbiont capture. Third, phylogenomic analyses converge on the origin of most eukaryotic genes of archaeal descent from within the archaeal evolutionary tree, specifically, the TACK superphylum. Fourth, evidence has been presented that the origin of the major archaeal phyla involved massive acquisition of bacterial genes. Taken together, these findings make the symbiogenetic scenario for the origin of eukaryotes considerably more plausible and the origin of the organizational complexity of eukaryotic cells more readily explainable than they appeared until recently.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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15
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Terwilliger TC, Bunkóczi G, Hung LW, Zwart PH, Smith JL, Akey DL, Adams PD. Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing. Acta Crystallogr D Struct Biol 2016; 72:346-58. [PMID: 26960122 PMCID: PMC4784666 DOI: 10.1107/s2059798315019269] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/12/2015] [Indexed: 12/19/2022] Open
Abstract
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. A simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment is presented. Here, the useful anomalous correlation is defined as the correlation of anomalous differences with ideal anomalous differences from the anomalous substructure. The useful anomalous correlation reflects the accuracy of the data and the absence of minor sites. The useful anomalous correlation also reflects the information available for estimating crystallographic phases once the substructure has been determined. In contrast, the anomalous signal (the peak height in a model-phased anomalous difference Fourier at the coordinates of atoms in the anomalous substructure) reflects the information available about each site in the substructure and is related to the ability to find the substructure. A theoretical analysis shows that the expected value of the anomalous signal is the product of the useful anomalous correlation, the square root of the ratio of the number of unique reflections in the data set to the number of sites in the substructure, and a function that decreases with increasing values of the atomic displacement factor for the atoms in the substructure. This means that the ability to find the substructure in a SAD experiment is increased by high data quality and by a high ratio of reflections to sites in the substructure, and is decreased by high atomic displacement factors for the substructure.
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Affiliation(s)
- Thomas C. Terwilliger
- Bioscience Division, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA
| | - Gábor Bunkóczi
- Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England
| | - Li-Wei Hung
- Physics Division, Los Alamos National Laboratory, Mail Stop D454, Los Alamos, NM 87545, USA
| | - Peter H. Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - David L. Akey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Paul D. Adams
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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16
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Terwilliger TC, Bunkóczi G, Hung LW, Zwart PH, Smith JL, Akey DL, Adams PD. Can I solve my structure by SAD phasing? Planning an experiment, scaling data and evaluating the useful anomalous correlation and anomalous signal. Acta Crystallogr D Struct Biol 2016; 72:359-74. [PMID: 26960123 PMCID: PMC4784667 DOI: 10.1107/s2059798315019403] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/13/2015] [Indexed: 01/15/2023] Open
Abstract
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. Here, algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment are described. A simple theoretical framework [Terwilliger et al. (2016), Acta Cryst. D72, 346-358] is used to develop methods for planning a SAD experiment, scaling SAD data sets and estimating the useful anomalous correlation and anomalous signal in a SAD data set. The phenix.plan_sad_experiment tool uses a database of solved and unsolved SAD data sets and the expected characteristics of a SAD data set to estimate the probability that the anomalous substructure will be found in the SAD experiment and the expected map quality that would be obtained if the substructure were found. The phenix.scale_and_merge tool scales unmerged SAD data from one or more crystals using local scaling and optimizes the anomalous signal by identifying the systematic differences among data sets, and the phenix.anomalous_signal tool estimates the useful anomalous correlation and anomalous signal after collecting SAD data and estimates the probability that the data set can be solved and the likely figure of merit of phasing.
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Affiliation(s)
- Thomas C. Terwilliger
- Bioscience Division, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA
| | - Gábor Bunkóczi
- Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England
| | - Li-Wei Hung
- Physics Division, Los Alamos National Laboratory, Mail Stop D454, Los Alamos, NM 87545, USA
| | - Peter H. Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - David L. Akey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Paul D. Adams
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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17
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Izoré T, Kureisaite-Ciziene D, McLaughlin SH, Löwe J. Crenactin forms actin-like double helical filaments regulated by arcadin-2. eLife 2016; 5:e21600. [PMID: 27852434 PMCID: PMC5173319 DOI: 10.7554/elife.21600] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 11/14/2016] [Indexed: 01/27/2023] Open
Abstract
The similarity of eukaryotic actin to crenactin, a filament-forming protein from the crenarchaeon Pyrobaculum calidifontis supports the theory of a common origin of Crenarchaea and Eukaryotes. Monomeric structures of crenactin and actin are similar, although their filament architectures were suggested to be different. Here we report that crenactin forms bona fide double helical filaments that show exceptional similarity to eukaryotic F-actin. With cryo-electron microscopy and helical reconstruction we solved the structure of the crenactin filament to 3.8 Å resolution. When forming double filaments, the 'hydrophobic plug' loop in crenactin rearranges. Arcadin-2, also encoded by the arcade gene cluster, binds tightly with its C-terminus to the hydrophobic groove of crenactin. Binding is reminiscent of eukaryotic actin modulators such as cofilin and thymosin β4 and arcadin-2 is a depolymeriser of crenactin filaments. Our work further supports the theory of shared ancestry of Eukaryotes and Crenarchaea.
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Affiliation(s)
- Thierry Izoré
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | | | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom,
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18
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19
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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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21
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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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22
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Ettema TJG, Lindås AC, Hjort K, Poplawski AB, Kaessmann H, Grogan DW, Kelman Z, Andersson AF, Pelve EA, Lundgren M, Svärd SG. Rolf Bernander (1956-2014): pioneer of the archaeal cell cycle. Mol Microbiol 2014; 92:903-9. [PMID: 24865634 DOI: 10.1111/mmi.12608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2014] [Indexed: 11/29/2022]
Abstract
On 19 January 2014 Rolf ('Roffe') Bernander passed away unexpectedly. Rolf was a dedicated scientist; his research aimed at unravelling the cell biology of the archaeal domain of life, especially cell cycle-related questions, but he also made important contributions in other areas of microbiology. Rolf had a professor position in the Molecular Evolution programme at Uppsala University, Sweden for about 8 years, and in January 2013 he became chair professor at the Department of Molecular Biosciences, The Wenner-Gren Institute at Stockholm University in Sweden. Rolf was an exceptional colleague and will be deeply missed by his family and friends, and the colleagues and co-workers that he leaves behind in the scientific community. He will be remembered for his endless enthusiasm for science, his analytical mind, and his quirky sense of humour.
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Affiliation(s)
- Thijs J G Ettema
- Department of Cell- and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
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23
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van den Ent F, Izoré T, Bharat TA, Johnson CM, Löwe J. Bacterial actin MreB forms antiparallel double filaments. eLife 2014; 3:e02634. [PMID: 24843005 PMCID: PMC4051119 DOI: 10.7554/elife.02634] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/02/2014] [Indexed: 12/30/2022] Open
Abstract
Filaments of all actin-like proteins known to date are assembled from pairs of protofilaments that are arranged in a parallel fashion, generating polarity. In this study, we show that the prokaryotic actin homologue MreB forms pairs of protofilaments that adopt an antiparallel arrangement in vitro and in vivo. We provide an atomic view of antiparallel protofilaments of Caulobacter MreB as apparent from crystal structures. We show that a protofilament doublet is essential for MreB's function in cell shape maintenance and demonstrate by in vivo site-specific cross-linking the antiparallel orientation of MreB protofilaments in E. coli. 3D cryo-EM shows that pairs of protofilaments of Caulobacter MreB tightly bind to membranes. Crystal structures of different nucleotide and polymerisation states of Caulobacter MreB reveal conserved conformational changes accompanying antiparallel filament formation. Finally, the antimicrobial agents A22/MP265 are shown to bind close to the bound nucleotide of MreB, presumably preventing nucleotide hydrolysis and destabilising double protofilaments.DOI: http://dx.doi.org/10.7554/eLife.02634.001.
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Affiliation(s)
- Fusinita van den Ent
- Structural Studies Division, Medical Research Council - Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Thierry Izoré
- Structural Studies Division, Medical Research Council - Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Tanmay Am Bharat
- Structural Studies Division, Medical Research Council - Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Christopher M Johnson
- Protein and Nucleic Acid Chemistry Division, Medical Research Council - Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Jan Löwe
- Structural Studies Division, Medical Research Council - Laboratory of Molecular Biology, Cambridge, United Kingdom
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