1
|
Pende N, Wang J, Weber PM, Verheul J, Kuru E, Rittmann SKMR, Leisch N, VanNieuwenhze MS, Brun YV, den Blaauwen T, Bulgheresi S. Host-Polarized Cell Growth in Animal Symbionts. Curr Biol 2018; 28:1039-1051.e5. [PMID: 29576473 PMCID: PMC6611161 DOI: 10.1016/j.cub.2018.02.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 12/13/2017] [Accepted: 02/15/2018] [Indexed: 01/16/2023]
Abstract
To determine the fundamentals of cell growth, we must extend cell
biological studies to non-model organisms. Here, we investigated the growth
modes of the only two rods known to widen instead of elongating,
Candidatus Thiosymbion oneisti and Thiosymbion
hypermnestrae. These bacteria are attached by one pole to the surface of their
respective nematode hosts. By incubating live Ca. T. oneisti
and T. hypermnestrae with a peptidoglycan metabolic probe, we observed that the
insertion of new cell wall starts at the poles and proceeds inward,
concomitantly with FtsZ-based membrane constriction. Remarkably, in
Ca. T. hypermnestrae, the proximal, animal-attached pole
grows before the distal, free pole, indicating that the peptidoglycan synthesis
machinery is host oriented. Immunostaining of the symbionts with an antibody
against the actin homolog MreB revealed that it was arranged
medially—that is, parallel to the cell long axis—throughout the
symbiont life cycle. Given that depolymerization of MreB abolished newly
synthesized peptidoglycan insertion and impaired divisome assembly, we conclude
that MreB function is required for symbiont widening and division. In
conclusion, our data invoke a reassessment of the localization and function of
the bacterial actin homolog. Pende et al. show that cell growth is host oriented in two marine
nematode-attached bacteria. In contrast to what is observed in model rods, the
actin homolog MreB of the symbionts is arranged parallel to the cell long axis
throughout the cell cycle. This medial MreB ring is essential for symbiont
growth and division.
Collapse
Affiliation(s)
- Nika Pende
- University of Vienna, Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, Althanstrasse 14, 1090 Vienna, Austria
| | - Jinglan Wang
- Bacterial Cell Biology and Physiology Swammerdam Institute for Life Sciences, University of Amsterdam, De Boelelaan 1108, 1081 Amsterdam, the Netherlands
| | - Philipp M Weber
- University of Vienna, Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, Althanstrasse 14, 1090 Vienna, Austria
| | - Jolanda Verheul
- Bacterial Cell Biology and Physiology Swammerdam Institute for Life Sciences, University of Amsterdam, De Boelelaan 1108, 1081 Amsterdam, the Netherlands
| | - Erkin Kuru
- Department of Genetics, Harvard Medical School NRB, 77 Avenue Louis Pasteur, Boston, MA, USA
| | - Simon K-M R Rittmann
- University of Vienna, Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, Althanstrasse 14, 1090 Vienna, Austria
| | - Nikolaus Leisch
- University of Vienna, Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, Althanstrasse 14, 1090 Vienna, Austria
| | | | - Yves V Brun
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Tanneke den Blaauwen
- Bacterial Cell Biology and Physiology Swammerdam Institute for Life Sciences, University of Amsterdam, De Boelelaan 1108, 1081 Amsterdam, the Netherlands
| | - Silvia Bulgheresi
- University of Vienna, Department of Ecogenomics and Systems Biology, Archaeal Biology and Ecogenomics Division, Althanstrasse 14, 1090 Vienna, Austria.
| |
Collapse
|
2
|
Wasnik V, Wang H, Wingreen NS, Mukhopadhyay R. Physical model of protein cluster positioning in growing bacteria. NEW JOURNAL OF PHYSICS 2017; 19:105004. [PMID: 29628783 PMCID: PMC5885638 DOI: 10.1088/1367-2630/aa8247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chemotaxic receptors in bacteria form clusters at cell poles and also laterally, and this clustering plays an important role in signal transduction. These clusters were found to be periodically arranged on the surface of the bacterium Escherichia coli, independent of any known positioning mechanism. In this work we extend a model based on diffusion and aggregation to more realistic geometries and present a means based on "bursty" protein production to distinguish spontaneous positioning from an independently existing positioning mechanism. We also consider the case of isotropic cellular growth and characterize the degree of order arising spontaneously. Our model could also be relevant for other examples of periodically positioned protein clusters in bacteria.
Collapse
Affiliation(s)
- Vaibhav Wasnik
- Department of Physics, Clark University, Worcester, MA 01610
| | - Hui Wang
- Department of Physics, Clark University, Worcester, MA 01610
| | - Ned S Wingreen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | | |
Collapse
|
3
|
Gunasinghe SD, Webb CT, Elgass KD, Hay ID, Lithgow T. Super-Resolution Imaging of Protein Secretion Systems and the Cell Surface of Gram-Negative Bacteria. Front Cell Infect Microbiol 2017; 7:220. [PMID: 28611954 PMCID: PMC5447050 DOI: 10.3389/fcimb.2017.00220] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/12/2017] [Indexed: 12/28/2022] Open
Abstract
Gram-negative bacteria have a highly evolved cell wall with two membranes composed of complex arrays of integral and peripheral proteins, as well as phospholipids and glycolipids. In order to sense changes in, respond to, and exploit their environmental niches, bacteria rely on structures assembled into or onto the outer membrane. Protein secretion across the cell wall is a key process in virulence and other fundamental aspects of bacterial cell biology. The final stage of protein secretion in Gram-negative bacteria, translocation across the outer membrane, is energetically challenging so sophisticated nanomachines have evolved to meet this challenge. Advances in fluorescence microscopy now allow for the direct visualization of the protein secretion process, detailing the dynamics of (i) outer membrane biogenesis and the assembly of protein secretion systems into the outer membrane, (ii) the spatial distribution of these and other membrane proteins on the bacterial cell surface, and (iii) translocation of effector proteins, toxins and enzymes by these protein secretion systems. Here we review the frontier research imaging the process of secretion, particularly new studies that are applying various modes of super-resolution microscopy.
Collapse
Affiliation(s)
- Sachith D Gunasinghe
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash UniversityClayton, VIC, Australia
| | - Chaille T Webb
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash UniversityClayton, VIC, Australia
| | | | - Iain D Hay
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash UniversityClayton, VIC, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash UniversityClayton, VIC, Australia
| |
Collapse
|
4
|
Huang KH, Mychack A, Tchorzewski L, Janakiraman A. Characterization of the FtsZ C-Terminal Variable (CTV) Region in Z-Ring Assembly and Interaction with the Z-Ring Stabilizer ZapD in E. coli Cytokinesis. PLoS One 2016; 11:e0153337. [PMID: 27088231 PMCID: PMC4835091 DOI: 10.1371/journal.pone.0153337] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 03/28/2016] [Indexed: 12/19/2022] Open
Abstract
Polymerization of a ring-like cytoskeletal structure, the Z-ring, at midcell is a highly conserved feature in virtually all bacteria. The Z-ring is composed of short protofilaments of the tubulin homolog FtsZ, randomly arranged and held together through lateral interactions. In vitro, lateral associations between FtsZ protofilaments are stabilized by crowding agents, high concentrations of divalent cations, or in some cases, low pH. In vivo, the last 4–10 amino acid residues at the C-terminus of FtsZ (the C-terminal variable region, CTV) have been implicated in mediating lateral associations between FtsZ protofilaments through charge shielding. Multiple Z-ring associated proteins (Zaps), also promote lateral interactions between FtsZ protofilaments to stabilize the FtsZ ring in vivo. Here we characterize the complementary role/s of the CTV of E. coli FtsZ and the FtsZ-ring stabilizing protein ZapD, in FtsZ assembly. We show that the net charge of the FtsZ CTV not only affects FtsZ protofilament bundling, confirming earlier observations, but likely also the length of the FtsZ protofilaments in vitro. The CTV residues also have important consequences for Z-ring assembly and interaction with ZapD in the cell. ZapD requires the FtsZ CTV region for interaction with FtsZ in vitro and for localization to midcell in vivo. Our data suggest a mechanism in which the CTV residues, particularly K380, facilitate a conformation for the conserved carboxy-terminal residues in FtsZ, that lie immediately N-terminal to the CTV, to enable optimal contact with ZapD. Further, phylogenetic analyses suggest a correlation between the nature of FtsZ CTV residues and the presence of ZapD in the β- γ-proteobacterial species.
Collapse
Affiliation(s)
- Kuo-Hsiang Huang
- Department of Biology, City College of CUNY, 160 Convent Avenue, MR 526, New York, NY, United States of America
- The Graduate Center of CUNY, 365 Fifth Avenue, New York, NY, United States of America
| | - Aaron Mychack
- Department of Biology, City College of CUNY, 160 Convent Avenue, MR 526, New York, NY, United States of America
- The Graduate Center of CUNY, 365 Fifth Avenue, New York, NY, United States of America
| | - Lukasz Tchorzewski
- Department of Biology, City College of CUNY, 160 Convent Avenue, MR 526, New York, NY, United States of America
| | - Anuradha Janakiraman
- Department of Biology, City College of CUNY, 160 Convent Avenue, MR 526, New York, NY, United States of America
- The Graduate Center of CUNY, 365 Fifth Avenue, New York, NY, United States of America
- * E-mail:
| |
Collapse
|
5
|
Abstract
The autotransporter and two-partner secretion (TPS) pathways are used by E. coli and many other Gram-negative bacteria to delivervirulence factors into the extracellular milieu.Autotransporters arecomprised of an N-terminal extracellular ("passenger") domain and a C-terminal β barrel domain ("β domain") that anchors the protein to the outer membrane and facilitates passenger domain secretion. In the TPS pathway, a secreted polypeptide ("exoprotein") is coordinately expressed with an outer membrane protein that serves as a dedicated transporter. Bothpathways are often grouped together under the heading "type V secretion" because they have many features in common and are used for the secretion of structurally related polypeptides, but it is likely that theyhave distinct evolutionary origins. Although it was proposed many years ago that autotransporterpassenger domains are transported across the outer membrane through a channel formed by the covalently linked β domain, there is increasing evidence that additional factors are involved in the translocation reaction. Furthermore, details of the mechanism of protein secretion through the TPS pathway are only beginning to emerge. In this chapter I discussour current understanding ofboth early and late steps in the biogenesis of polypeptides secreted through type V pathways and current modelsofthe mechanism of secretion.
Collapse
|
6
|
Biogenesis of YidC cytoplasmic membrane substrates is required for positioning of autotransporter IcsA at future poles. J Bacteriol 2013; 196:624-32. [PMID: 24272775 DOI: 10.1128/jb.00840-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Localization of proteins to specific sites within bacterial cells is often critical to their function. In rod-shaped bacteria, proteins involved in diverse and important cell processes localize to the cell poles. The molecular mechanisms by which these proteins are targeted to the pole, however, are poorly understood. The Shigella autotransporter protein IcsA, which is localized to the pole on the surface of the bacterium, is targeted to the pole in the cytoplasm by a mechanism that is conserved across multiple Gram-negative bacterial species and has thus served as an important and informative model for studying polar localization. We present evidence that in Escherichia coli, the establishment of polar positional information recognized by IcsA requires the activity of the cytoplasmic membrane protein insertase YidC. We show that the role of YidC in IcsA localization is independent of the cell septation and cytokinesis proteins FtsQ and FtsEX. FtsQ is required for polar localization of IcsA and, based on cross-linking studies, is inserted in the vicinity of YidC, but, we find, is not dependent on YidC for membrane insertion. FtsEX is a YidC substrate, but we find that it is not required for polar localization of IcsA. These findings indicate that polar positional information recognized by IcsA depends on one or more membrane proteins that require YidC for proper membrane insertion.
Collapse
|
7
|
Identification of ZapD as a cell division factor that promotes the assembly of FtsZ in Escherichia coli. J Bacteriol 2012; 194:3189-98. [PMID: 22505682 DOI: 10.1128/jb.00176-12] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The tubulin homolog FtsZ forms a polymeric membrane-associated ring structure (Z ring) at midcell that establishes the site of division and provides an essential framework for the localization of a multiprotein molecular machine that promotes division in Escherichia coli. A number of regulatory proteins interact with FtsZ and modulate FtsZ assembly/disassembly processes, ensuring the spatiotemporal integrity of cytokinesis. The Z-associated proteins (ZapA, ZapB, and ZapC) belong to a group of FtsZ-regulatory proteins that exhibit functionally redundant roles in stabilizing FtsZ-ring assembly by binding and bundling polymeric FtsZ at midcell. In this study, we report the identification of ZapD (YacF) as a member of the E. coli midcell division machinery. Genetics and cell biological evidence indicate that ZapD requires FtsZ but not other downstream division proteins for localizing to midcell, where it promotes FtsZ-ring assembly via molecular mechanisms that overlap with ZapA. Biochemical evidence indicates that ZapD directly interacts with FtsZ and promotes bundling of FtsZ protofilaments. Similarly to ZapA, ZapB, and ZapC, ZapD is dispensable for division and therefore belongs to the growing group of FtsZ-associated proteins in E. coli that aid in the overall fitness of the division process.
Collapse
|
8
|
Abstract
Spatial organization within bacteria is fundamental to many cellular processes, although the basic mechanisms underlying localization of proteins to specific sites within bacteria are poorly understood. The study of protein positioning has been limited by a paucity of methods that allow rapid large-scale screening for mutants in which protein positioning is altered. We developed a genetic reporter system for protein localization to the pole within the bacterial cytoplasm that allows saturation screening for mutants in Escherichia coli in which protein localization is altered. Utilizing this system, we identify proteins required for proper positioning of the Shigella autotransporter IcsA. Autotransporters, widely distributed bacterial virulence proteins, are secreted at the bacterial pole. We show that the conserved cell division protein FtsQ is required for localization of IcsA and other autotransporters to the pole. We demonstrate further that this system can be applied to the study of proteins other than autotransporters that display polar positioning within bacterial cells. Many proteins localize to specific sites within bacterial cells, and localization to these sites is frequently critical to proper protein function. The mechanisms that underlie protein localization are incompletely understood, in part because of the paucity of methods that allow saturation screening for mutants in which protein localization is altered. We developed a genetic reporter assay that enables screening of bacterial populations for changes in localization of proteins to the bacterial pole, and we demonstrate the utility of the system in identifying factors required for proper localization of the polar Shigella autotransporter protein IcsA. Using this method, we identify the conserved cell division protein FtsQ as being required for positioning of IcsA to the bacterial pole. We demonstrate further that the requirement for FtsQ for polar positioning applies to other autotransporters and that the method can be applied to polar proteins other than autotransporters.
Collapse
|
9
|
The three-layered DNA uptake machinery at the cell pole in competent Bacillus subtilis cells is a stable complex. J Bacteriol 2011; 193:1633-42. [PMID: 21278288 DOI: 10.1128/jb.01128-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Many bacteria possess the ability to actively take up DNA from the environment and incorporate it into the chromosome. RecA protein is the key protein achieving homologous recombination. Several of the proteins involved in the transport of DNA across the cell envelope assemble at a single or both cell poles in competent Bacillus subtilis cells. We show that the presumed structure that transports DNA across the cell wall, the pseudopilus, also assembles at a single or both cell poles, while the membrane receptor, ComEA, forms a mobile layer throughout the cell membrane. All other known Com proteins, including the membrane permease, localize again to the cell pole, revealing that the uptake machinery has three distinct layers. In cells having two uptake machineries, one complex is occasionally mobile, with pairs of proteins moving together, suggesting that a complete complex may lose anchoring and become mobile. Overall, the cell pole provides stable anchoring. Only one of two uptake machineries assembles RecA protein, suggesting that only one is competent for DNA transfer. FRAP (fluorescence recovery after photobleaching) analyses show that in contrast to known multiprotein complexes, the DNA uptake machinery forms a highly stable complex, showing little or no exchange with unbound molecules. When cells are converted into round spheroplasts, the structure persists, revealing that the assembly is highly stable and does not require the cell pole for its maintenance. High stability may be important to fulfill the mechanical function in pulling DNA across two cell layers.
Collapse
|
10
|
Identification and characterization of ZapC, a stabilizer of the FtsZ ring in Escherichia coli. J Bacteriol 2011; 193:1405-13. [PMID: 21216995 DOI: 10.1128/jb.01258-10] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Escherichia coli, spatiotemporal control of cell division occurs at the level of the assembly/disassembly process of the essential cytoskeletal protein FtsZ. A number of regulators interact with FtsZ and modulate the dynamics of the assembled FtsZ ring at the midcell division site. In this article, we report the identification of an FtsZ stabilizer, ZapC (Z-associated protein C), in a protein localization screen conducted with E. coli. ZapC colocalizes with FtsZ at midcell and interacts directly with FtsZ, as determined by a protein-protein interaction assay in yeast. Cells lacking or overexpressing ZapC are slightly elongated and have aberrant FtsZ ring morphologies indicative of a role for ZapC in FtsZ regulation. We also demonstrate the ability of purified ZapC to promote lateral bundling of FtsZ in a sedimentation reaction visualized by transmission electron microscopy. While ZapC lacks sequence similarity with other nonessential FtsZ regulators, ZapA and ZapB, all three Zap proteins appear to play an important role in FtsZ regulation during rapid growth. Taken together, our results suggest a key role for lateral bundling of the midcell FtsZ polymers in maintaining FtsZ ring stability during division.
Collapse
|
11
|
Abstract
Like their eukaryotic counterparts, bacterial cells have a highly organized internal architecture. Here, we address the question of how proteins localize to particular sites in the cell and how they do so in a dynamic manner. We consider the underlying mechanisms that govern the positioning of proteins and protein complexes in the examples of the divisome, polar assemblies, cytoplasmic clusters, cytoskeletal elements, and organelles. We argue that geometric cues, self-assembly, and restricted sites of assembly are all exploited by the cell to specifically localize particular proteins that we refer to as anchor proteins. These anchor proteins in turn govern the localization of a whole host of additional proteins. Looking ahead, we speculate on the existence of additional mechanisms that contribute to the organization of bacterial cells, such as the nucleoid, membrane microdomains enriched in specific lipids, and RNAs with positional information.
Collapse
|
12
|
Ping L. The asymmetric flagellar distribution and motility of Escherichia coli. J Mol Biol 2010; 397:906-16. [PMID: 20156455 DOI: 10.1016/j.jmb.2010.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 02/03/2010] [Accepted: 02/08/2010] [Indexed: 10/19/2022]
Abstract
Rod-shaped bacteria such as Escherichia coli divide by binary fission. They inherit an old pole from the parent cell. The new pole is recently derived from the septum. Because the chemoreceptor accumulates linearly with time on the cell pole, the old pole carries more receptors than does the new pole. Here, further evidence is provided that the old pole appears more frequently at the rear when bacteria swim. This phenomenon had been observed, yet not extensively explored in the literature. The biased swimming orientation is the consequence of the asymmetric distribution of flagella over the cell surface. On about 75% of cells, there are more flagella on the old-pole half of the cell than on the new-pole half, regardless of growth conditions. Most flagella are lateral, and few were found on the cell pole per se. The asymmetric flagellar distribution makes cells more efficient in chemotaxis. Both swimming orientation and receptor localization are components of chemotaxis, by which bacteria follow environmental stimuli. If unipolarly flagellated cells, such as the swarmer cells of Caulobacter crescentus, are regarded as 100% polar with respect to chemotaxis, E. coli is about 75%. The difference is quantitative. The peritrichous flagellation might enhance the motility and chemotaxis in the viscous environment of enteric bacteria.
Collapse
Affiliation(s)
- Liyan Ping
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knoell-Strasse 8, 07745 Jena, Germany.
| |
Collapse
|
13
|
Abstract
Prokaryotes come in a wide variety of shapes, determined largely by natural selection, physical constraints, and patterns of cell growth and division. Because of their relative simplicity, bacterial cells are excellent models for how genes and proteins can directly determine morphology. Recent advances in cytological methods for bacteria have shown that distinct cytoskeletal filaments composed of actin and tubulin homologs are important for guiding growth patterns of the cell wall in bacteria, and that the glycan strands that constitute the wall are generally perpendicular to the direction of growth. This cytoskeleton-directed cell wall patterning is strikingly reminiscent of how plant cell wall growth is regulated by microtubules. In rod-shaped bacilli, helical cables of actin-like MreB protein stretch along the cell length and orchestrate elongation of the cell wall, whereas the tubulin-like FtsZ protein directs formation of the division septum and the resulting cell poles. The overlap and interplay between these two systems and the peptidoglycan-synthesizing enzymes they recruit are the major driving forces of cylindrical shapes. Round cocci, on the other hand, have lost their MreB cables and instead must grow mainly via their division septum, giving them their characteristic round or ovoid shapes. Other bacteria that lack MreB homologs or even cell walls use distinct cytoskeletal systems to maintain their distinct shapes. Here I review what is known about the mechanisms that determine the shape of prokaryotic cells.
Collapse
Affiliation(s)
- William Margolin
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
| |
Collapse
|
14
|
García Véscovi E, Sciara MI, Castelli ME. Two component systems in the spatial program of bacteria. Curr Opin Microbiol 2010; 13:210-8. [PMID: 20138002 DOI: 10.1016/j.mib.2009.12.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 12/29/2009] [Accepted: 12/31/2009] [Indexed: 11/26/2022]
Abstract
Despite being considered a relatively simple form of life, bacteria have revealed a high degree of structural organization, with the spatial destination of their components precisely regulated within the cell. Nevertheless, the primary signals that dictate differential distribution of cellular building blocks and physiological processes remain in most cases largely undisclosed. Signal transduction systems are no exception within this three-dimensional organization and two-component systems (TCS) involved in controlling cell division, differentiation, chemotaxis and virulence show specific and/or dynamic localization, engaging in the spatial program of the bacterial cell.
Collapse
Affiliation(s)
- Eleonora García Véscovi
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina.
| | | | | |
Collapse
|
15
|
Janakiraman A, Fixen KR, Gray AN, Niki H, Goldberg MB. A genome-scale proteomic screen identifies a role for DnaK in chaperoning of polar autotransporters in Shigella. J Bacteriol 2009; 191:6300-11. [PMID: 19684128 PMCID: PMC2753027 DOI: 10.1128/jb.00833-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 08/07/2009] [Indexed: 11/20/2022] Open
Abstract
Autotransporters are outer membrane proteins that are widely distributed among gram-negative bacteria. Like other autotransporters, the Shigella autotransporter IcsA, which is required for actin assembly during infection, is secreted at the bacterial pole. In the bacterial cytoplasm, IcsA localizes to poles and potential cell division sites independent of the cell division protein FtsZ. To identify bacterial proteins involved in the targeting of IcsA to the pole in the bacterial cytoplasm, we screened a genome-scale library of Escherichia coli proteins tagged with green fluorescent protein (GFP) for those that displayed a localization pattern similar to that of IcsA-GFP in cells that lack functional FtsZ using a strain carrying a temperature-sensitive ftsZ allele. For each protein that mimicked the localization of IcsA-GFP, we tested whether IcsA localization was dependent on the presence of the protein. Although these approaches did not identify a polar receptor for IcsA, the cytoplasmic chaperone DnaK both mimicked IcsA localization at elevated temperatures as a GFP fusion and was required for the localization of IcsA to the pole in the cytoplasm of E. coli. DnaK was also required for IcsA secretion at the pole in Shigella flexneri. The localization of DnaK-GFP to poles and potential cell division sites was dependent on elevated growth temperature and independent of the presence of IcsA or functional FtsZ; native DnaK was found to be enhanced at midcell and the poles. A second Shigella autotransporter, SepA, also required DnaK for secretion, consistent with a role of DnaK more generally in the chaperoning of autotransporter proteins in the bacterial cytoplasm.
Collapse
Affiliation(s)
- Anuradha Janakiraman
- Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts 02139, USA
| | | | | | | | | |
Collapse
|
16
|
Vishnyakov IE, Borchsenius SN, Basovskii YI, Levitskii SA, Lazarev VN, Snigirevskaya ES, Komissarchik YY. Localization of division protein FtsZ in Mycoplasma hominis. ACTA ACUST UNITED AC 2009. [DOI: 10.1134/s1990519x09030079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
17
|
Self-organization of the Escherichia coli chemotaxis network imaged with super-resolution light microscopy. PLoS Biol 2009; 7:e1000137. [PMID: 19547746 PMCID: PMC2691949 DOI: 10.1371/journal.pbio.1000137] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 05/14/2009] [Indexed: 11/19/2022] Open
Abstract
Photoactivated localization microscopy analysis of chemotaxis receptors in bacteria suggests that the non-random organization of these proteins results from random self-assembly of clusters without direct cytoskeletal involvement or active transport. The Escherichia coli chemotaxis network is a model system for biological signal processing. In E. coli, transmembrane receptors responsible for signal transduction assemble into large clusters containing several thousand proteins. These sensory clusters have been observed at cell poles and future division sites. Despite extensive study, it remains unclear how chemotaxis clusters form, what controls cluster size and density, and how the cellular location of clusters is robustly maintained in growing and dividing cells. Here, we use photoactivated localization microscopy (PALM) to map the cellular locations of three proteins central to bacterial chemotaxis (the Tar receptor, CheY, and CheW) with a precision of 15 nm. We find that cluster sizes are approximately exponentially distributed, with no characteristic cluster size. One-third of Tar receptors are part of smaller lateral clusters and not of the large polar clusters. Analysis of the relative cellular locations of 1.1 million individual proteins (from 326 cells) suggests that clusters form via stochastic self-assembly. The super-resolution PALM maps of E. coli receptors support the notion that stochastic self-assembly can create and maintain approximately periodic structures in biological membranes, without direct cytoskeletal involvement or active transport. Cells arrange their components—proteins, lipids, and nucleic acids—in organized and reproducible ways to optimize the activities of these components and, therefore, to improve cell efficiency and survival. Eukaryotic cells have a complex arrangement of subcellular structures such as membrane-bound organelles and cytoskeletal transport systems. However, subcellular organization is also important in prokaryotic cells, including rod-shaped bacteria such as E. coli, most of which lack such well-developed systems of organelles and motor proteins for transporting cellular cargoes. In fact, it has remained somewhat mysterious how bacteria are able to organize and spatially segregate their interiors. The E. coli chemotaxis network, a system important for the bacterial response to environmental cues, is one of the best-understood biological signal transduction pathways and serves as a useful model for studying bacterial spatial organization because its components display a nonrandom, periodic distribution in mature cells. Chemotaxis receptors aggregate and cluster into large sensory complexes that localize to the poles of bacteria. To understand how these clusters form and what controls their size and density, we use ultrahigh-resolution light microscopy, called photoactivated localization microscopy (PALM), to visualize individual chemoreceptors in single E. coli cells. From these high-resolution images, we determined that receptors are not actively distributed or attached to specific locations in cells. Instead, we show that random receptor diffusion and receptor–receptor interactions are sufficient to generate the observed complex, ordered pattern. This simple mechanism, termed stochastic self-assembly, may prove to be widespread in both prokaryotic and eukaryotic cells.
Collapse
|
18
|
Wang H, Wingreen NS, Mukhopadhyay R. Self-organized periodicity of protein clusters in growing bacteria. PHYSICAL REVIEW LETTERS 2008; 101:218101. [PMID: 19113453 DOI: 10.1103/physrevlett.101.218101] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Indexed: 05/27/2023]
Abstract
Chemotaxis receptors in E. coli form clusters at the cell poles and also laterally along the cell body, and this clustering plays an important role in signal transduction. Recently, experiments using fluorescence imaging have shown that, during cell growth, lateral clusters form at positions approximately periodically spaced along the cell body. In this Letter, we demonstrate within a lattice model that such spatial organization could arise spontaneously from a stochastic nucleation mechanism. The same mechanism may explain the recent observation of periodic aggregates of misfolded proteins in E. coli.
Collapse
Affiliation(s)
- Hui Wang
- Department of Physics, Clark University, Worcester, Massachusetts 01610, USA
| | | | | |
Collapse
|
19
|
Affiliation(s)
- Dylan M. Morris
- Division of Biology, California Institute of Technology, Pasadena, California 91125;
| | - Grant J. Jensen
- Division of Biology, California Institute of Technology, Pasadena, California 91125;
| |
Collapse
|
20
|
Edgar R, Rokney A, Feeney M, Semsey S, Kessel M, Goldberg MB, Adhya S, Oppenheim AB. Bacteriophage infection is targeted to cellular poles. Mol Microbiol 2008; 68:1107-16. [PMID: 18363799 PMCID: PMC3740151 DOI: 10.1111/j.1365-2958.2008.06205.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The poles of bacteria exhibit several specialized functions related to the mobilization of DNA and certain proteins. To monitor the infection of Escherichia coli cells by light microscopy, we developed procedures for the tagging of mature bacteriophages with quantum dots. Surprisingly, most of the infecting phages were found attached to the bacterial poles. This was true for a number of temperate and virulent phages of E. coli that use widely different receptors and for phages infecting Yersinia pseudotuberculosis and Vibrio cholerae. The infecting phages colocalized with the polar protein marker IcsA-GFP. ManY, an E. coli protein that is required for phage lambda DNA injection, was found to localize to the bacterial poles as well. Furthermore, labelling of lambda DNA during infection revealed that it is injected and replicated at the polar region of infection. The evolutionary benefits that lead to this remarkable preference for polar infections may be related to lambda's developmental decision as well as to the function of poles in the ability of bacterial cells to communicate with their environment and in gene regulation.
Collapse
Affiliation(s)
- Rotem Edgar
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Den Blaauwen T, de Pedro MA, Nguyen-Distèche M, Ayala JA. Morphogenesis of rod-shaped sacculi. FEMS Microbiol Rev 2008; 32:321-44. [DOI: 10.1111/j.1574-6976.2007.00090.x] [Citation(s) in RCA: 235] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
22
|
Asymmetric segregation of protein aggregates is associated with cellular aging and rejuvenation. Proc Natl Acad Sci U S A 2008; 105:3076-81. [PMID: 18287048 DOI: 10.1073/pnas.0708931105] [Citation(s) in RCA: 385] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aging, defined as a decrease in reproduction rate with age, is a fundamental characteristic of all living organisms down to bacteria. Yet we know little about the causal molecular mechanisms of aging within the in vivo context of a wild-type organism. One of the prominent markers of aging is protein aggregation, associated with cellular degeneracy in many age-related diseases, although its in vivo dynamics and effect are poorly understood. We followed the appearance and inheritance of spontaneous protein aggregation within lineages of Escherichia coli grown under nonstressed conditions using time-lapse microscopy and a fluorescently tagged chaperone (IbpA) involved in aggregate processing. The fluorescent marker is shown to faithfully identify in vivo the localization of aggregated proteins, revealing their accumulation upon cell division in cells with older poles. This accretion is associated with >30% of the loss of reproductive ability (aging) in these cells relative to the new-pole progeny, devoid of parental inclusion bodies, that exhibit rejuvenation. This suggests an asymmetric strategy whereby dividing cells segregate damage at the expense of aging individuals, resulting in the perpetuation of the population.
Collapse
|
23
|
Dautin N, Bernstein HD. Protein secretion in gram-negative bacteria via the autotransporter pathway. Annu Rev Microbiol 2007; 61:89-112. [PMID: 17506669 DOI: 10.1146/annurev.micro.61.080706.093233] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autotransporters are a large and diverse superfamily of proteins produced by pathogenic gram-negative bacteria that are composed of an N-terminal passenger domain, which typically harbors a virulence function, and a C-terminal beta domain. It has long been known that the beta domain anchors the protein to the outer membrane and facilitates transport of the passenger domain into the extracellular space. Despite the apparent simplicity of the autotransporter pathway, several aspects of autotransporter biogenesis remain poorly understood, most notably the mechanism by which the passenger domain is translocated across the outer membrane. Here we review recent evidence that the enormous sequence diversity of both passenger and beta domains belies a remarkable conservation of structure. We also discuss insights into each stage of autotransporter biogenesis that have emerged from recent structural, biochemical, and imaging studies.
Collapse
Affiliation(s)
- Nathalie Dautin
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0538, USA.
| | | |
Collapse
|
24
|
Srivastava P, Demarre G, Karpova TS, McNally J, Chattoraj DK. Changes in nucleoid morphology and origin localization upon inhibition or alteration of the actin homolog, MreB, of Vibrio cholerae. J Bacteriol 2007; 189:7450-63. [PMID: 17704222 PMCID: PMC2168437 DOI: 10.1128/jb.00362-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MreB is an actin homolog required for the morphogenesis of most rod-shaped bacteria and for other functions, including chromosome segregation. In Caulobacter crescentus and Escherichia coli, the protein seems to play a role in the segregation of sister origins, but its role in Bacillus subtilis chromosome segregation is less clear. To help clarify its role in segregation, we have here studied the protein in Vibrio cholerae, whose chromosome I segregates like the one in C. crescentus and whose chromosome II like the one in E. coli or B. subtilis. The properties of Vibrio MreB were similar to those of its homologs in other bacteria in that it formed dynamic helical filaments, was essential for viability, and was inhibited by the drug A22. Wild-type (WT) cells exposed to A22 became spherical and larger. The nucleoids enlarged correspondingly, and the origin positions for both the chromosomes no longer followed any fixed pattern. However, the sister origins separated, unlike the situation in other bacteria. In mutants isolated as A22 resistant, the nucleoids in some cases appeared compacted even when the cell shape was nearly normal. In these cells, the origins of chromosome I were at the distal edges of the nucleoid but not all the way to the poles where they normally reside. The sister origins of chromosome II also separated less. Thus, it appears that the inhibition or alteration of Vibrio MreB can affect both the nucleoid morphology and origin localization.
Collapse
Affiliation(s)
- Preeti Srivastava
- Laboratory of Biochemistry and Molecular Biology, NCI, NIH, Bethesda, MD 20892-4260, USA
| | | | | | | | | |
Collapse
|
25
|
Rajalahti T, Huang F, Klement MR, Pisareva T, Edman M, Sjöström M, Wieslander A, Norling B. Proteins in different Synechocystis compartments have distinguishing N-terminal features: a combined proteomics and multivariate sequence analysis. J Proteome Res 2007; 6:2420-34. [PMID: 17508731 DOI: 10.1021/pr0605973] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacteria have a cell envelope consisting of a plasma membrane, a periplasmic space with a peptidoglycan layer, and an outer membrane. A third, separate membrane system, the intracellular thylakoid membranes, is the site for both photosynthesis and respiration. All membranes and luminal spaces have unique protein compositions, which impose an intriguing mechanism for protein sorting of extracytoplasmic proteins due to single sets of translocation protein genes. It is shown here by multivariate sequence analyses of many experimentally identified proteins in Synechocystis, that proteins routed for the different extracytosolic compartments have correspondingly different physicochemical properties in their signal peptide and mature N-terminal segments. The full-length mature sequences contain less significant information. From these multivariate, N-terminal property-profile models for proteins with single experimental localization, proteins with ambiguous localization could, to a large extent, be predicted to a defined compartment. The sequence properties involve amino acids varying especially in volume and polarizability and at certain positions in the sequence segments, in a manner typical for the various compartment classes. Potential means of the cell to recognize the property features are discussed, involving the translocation channels and two Type I signal peptidases with different cellular localization, and charge features at their membrane interfaces.
Collapse
Affiliation(s)
- Tarja Rajalahti
- Department of Chemistry, University of Bergen, Bergen, Norway
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Thiem S, Kentner D, Sourjik V. Positioning of chemosensory clusters in E. coli and its relation to cell division. EMBO J 2007; 26:1615-23. [PMID: 17332753 PMCID: PMC1829377 DOI: 10.1038/sj.emboj.7601610] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 01/25/2007] [Indexed: 11/09/2022] Open
Abstract
Chemotaxis receptors and associated signalling proteins in Escherichia coli form clusters that consist of thousands of molecules and are the largest native protein complexes described to date in bacteria. Clusters are located at the cell poles and laterally along the cell body, and play an important role in signal transduction. Much work has been done to study the structure and function of receptor clusters, but the significance of their positioning and the underlying mechanisms are not understood. Here, we used fluorescence imaging to study cluster distribution and follow cluster dynamics during cell growth. Our data show that lateral clusters localise to specific periodic positions along the cell body, which mark future division sites and are involved in the localisation of the replication machinery. The chemoreceptor cluster positioning is thus intricately related to the overall structure and division of an E. coli cell.
Collapse
Affiliation(s)
- Sebastian Thiem
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - David Kentner
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - Victor Sourjik
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, Heidelberg 69120, Germany. Tel.: +49 6221 546858; Fax: +49 6221 545894; E-mail:
| |
Collapse
|
27
|
Ebersbach G, Jacobs-Wagner C. Exploration into the spatial and temporal mechanisms of bacterial polarity. Trends Microbiol 2007; 15:101-8. [PMID: 17275310 DOI: 10.1016/j.tim.2007.01.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 01/04/2007] [Accepted: 01/23/2007] [Indexed: 10/23/2022]
Abstract
The recognition of bacterial asymmetry is not new: the first high-resolution microscopy studies revealed that bacteria come in a multitude of shapes and sometimes carry asymmetrically localized external structures such as flagella on the cell surface. Even so, the idea that bacteria could have an inherent overall polarity, which affects not only their outer appearance but also many of their vital processes, has only recently been appreciated. In this review, we focus on recent advances in our understanding of the molecular mechanisms underlying the establishment of polarized functions and cell polarity in bacteria.
Collapse
Affiliation(s)
- Gitte Ebersbach
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | | |
Collapse
|
28
|
Pradel N, Santini CL, Bernadac A, Shih YL, Goldberg MB, Wu LF. Polar positional information in Escherichia coli spherical cells. Biochem Biophys Res Commun 2007; 353:493-500. [PMID: 17188233 DOI: 10.1016/j.bbrc.2006.12.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 12/06/2006] [Indexed: 11/23/2022]
Abstract
Shigella surface protein IcsA and its cytoplasmic derivatives are localized to the old pole of rod-shaped cells when expressed in Escherichia coli. In spherical mreB cells, IcsA is targeted to ectopic sites and close to one extremity of actin-like MamK filament. To gain insight into the properties of the sites containing polar material, we studied the IcsA localization in spherical cells. GFP was exported into the periplasm via the Tat pathway and used as a periplasmic space marker. GFP displayed zonal fluorescence in both mreB and rodA-pbpA spherical E. coli cells, indicating an uneven periplasmic space. Deconvolution images revealed that the cytoplasmic IcsA fused to mCherry was localized outside or at the edge of the GFP zones. These observations strongly suggest that polar material is restricted to the positions where the periplasm possesses particular structural or biochemical properties.
Collapse
Affiliation(s)
- Nathalie Pradel
- Laboratoire de Chimie Bactérienne, UPR9043, Institut de Biologie Structurale et Microbiologie, CNRS, 31 chemin Joseph Aiguier, F-13402 Marseille cedex 20, France
| | | | | | | | | | | |
Collapse
|
29
|
Watt RM, Wang J, Leong M, Kung HF, Cheah KS, Liu D, Danchin A, Huang JD. Visualizing the proteome of Escherichia coli: an efficient and versatile method for labeling chromosomal coding DNA sequences (CDSs) with fluorescent protein genes. Nucleic Acids Res 2007; 35:e37. [PMID: 17272300 PMCID: PMC1874593 DOI: 10.1093/nar/gkl1158] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
To investigate the feasibility of conducting a genomic-scale protein labeling and localization study in Escherichia coli, a representative subset of 23 coding DNA sequences (CDSs) was selected for chromosomal tagging with one or more fluorescent protein genes (EGFP, EYFP, mRFP1, DsRed2). We used λ-Red recombination to precisely and efficiently position PCR-generated DNA targeting cassettes containing a fluorescent protein gene and an antibiotic resistance marker, at the C-termini of the CDSs of interest, creating in-frame fusions under the control of their native promoters. We incorporated cre/loxP and flpe/frt technology to enable multiple rounds of chromosomal tagging events to be performed sequentially with minimal disruption to the target locus, thus allowing sets of proteins to be co-localized within the cell. The visualization of labeled proteins in live E. coli cells using fluorescence microscopy revealed a striking variety of distributions including: membrane and nucleoid association, polar foci and diffuse cytoplasmic localization. Fifty of the fifty-two independent targeting experiments performed were successful, and 21 of the 23 selected CDSs could be fluorescently visualized. Our results show that E. coli has an organized and dynamic proteome, and demonstrate that this approach is applicable for tagging and (co-) localizing CDSs on a genome-wide scale.
Collapse
Affiliation(s)
- Rory M. Watt
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Jing Wang
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Meikid Leong
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Hsiang-fu Kung
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Kathryn S.E. Cheah
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Depei Liu
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Antoine Danchin
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Jian-Dong Huang
- Open Laboratory of Chemical Biology, The Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China, Department of Biochemistry, The University of Hong Kong, 3/F Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China, The Center for Emerging Infectious Diseases, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China, National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) & Peking Union Medical College (PUMC), Beijing 100005, P.R. China, Unité GGB, CNRS URA 2171, Institut Pasteur, 28 rue Dr. Roux, 75015 Paris, France and HKU-Pasteur Research Centre, Dexter HC Man Building, 8, Sassoon Road, Pokfulam, Hong Kong SAR, China
- *To whom correspondence should be addressed. (+852) 2819 2810(+852) 2855 1254
| |
Collapse
|
30
|
Abstract
In recent years it has been shown that bacteria contain a number of cytoskeletal structures. The bacterial cytoplasmic elements include homologs of the three major types of eukaryotic cytoskeletal proteins (actin, tubulin, and intermediate filament proteins) and a fourth group, the MinD-ParA group, that appears to be unique to bacteria. The cytoskeletal structures play important roles in cell division, cell polarity, cell shape regulation, plasmid partition, and other functions. The proteins self-assemble into filamentous structures in vitro and form intracellular ordered structures in vivo. In addition, there are a number of filamentous bacterial elements that may turn out to be cytoskeletal in nature. This review attempts to summarize and integrate the in vivo and in vitro aspects of these systems and to evaluate the probable future directions of this active research field.
Collapse
Affiliation(s)
- Yu-Ling Shih
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06032, USA
| | | |
Collapse
|
31
|
Peters V, Rehm BHA. In vivo monitoring of PHA granule formation using GFP-labeled PHA synthases. FEMS Microbiol Lett 2006; 248:93-100. [PMID: 15963662 DOI: 10.1016/j.femsle.2005.05.027] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 04/27/2005] [Accepted: 05/16/2005] [Indexed: 10/25/2022] Open
Abstract
For the first time a functional protein was fused to a PHA synthase resulting in PHA granule formation and display of the respective function at the PHA granule surface. The GFP reporter protein was N-terminally fused to the class I PHA synthase of Cupriavidus necator (PhaC) and the class II PHA synthase of Pseudomonas aeruginosa PAO1 (PhaC1), respectively, while maintaining PHA synthase activity and PHA granule formation. Fluorescence microscopy studies of GFP-PHA synthase attached to emerging PHA granules indicated that emerging PHA granules locate to cell poles and to midcell representing the future cell poles. A rapid oscillating movement of GFP-PHA synthase foci from pole to pole was observed. In cell division impaired Escherichia coli, PHA granules were localized between nucleoids at regular spacing suggesting that nucleoid occlusion occurred. Accordingly, anucleate regions of the E. coli mukB mutant showed no regular spacing, but PHA granules with twofold increased diameter were formed. First evidence was provided that the cell division and the localization of GFP-PHA synthase foci are in vivo co-located.
Collapse
Affiliation(s)
- Verena Peters
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | | |
Collapse
|
32
|
Abstract
Binary fission of many prokaryotes as well as some eukaryotic organelles depends on the FtsZ protein, which self-assembles into a membrane-associated ring structure early in the division process. FtsZ is homologous to tubulin, the building block of the microtubule cytoskeleton in eukaryotes. Recent advances in genomics and cell-imaging techniques have paved the way for the remarkable progress in our understanding of fission in bacteria and organelles.
Collapse
Affiliation(s)
- William Margolin
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, 6431 Fannin, Houston, Texas 77030, USA.
| |
Collapse
|
33
|
Abstract
The site of cell division in bacterial cells is placed with high fidelity at a designated position, usually the midpoint of the cell. In normal cell division in Escherichia coli this is accomplished by the action of the Min proteins, which maintain a high concentration of a septation inhibitor near the ends of the cell, and a low concentration at midcell. This leaves the midcell site as the only available location for formation of the division septum. In other species, such as Bacillus subtilis, this general paradigm is maintained, although some of the proteins differ and the mechanisms used to localize the proteins vary. A second mechanism of negative regulation, the nucleoid-occlusion system, prevents septa forming over nucleoids. This system functions in Gram-negative and Gram-positive bacteria, and is especially important in cells that lack the Min system or in cells in which nucleoid replication or segregation are defective. Here, we review the latest findings on these two systems.
Collapse
Affiliation(s)
- Lawrence Rothfield
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
| | | | | |
Collapse
|
34
|
Nilsen T, Yan AW, Gale G, Goldberg MB. Presence of multiple sites containing polar material in spherical Escherichia coli cells that lack MreB. J Bacteriol 2005; 187:6187-96. [PMID: 16109960 PMCID: PMC1196171 DOI: 10.1128/jb.187.17.6187-6196.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In rod-shaped bacteria, certain proteins are specifically localized to the cell poles. The nature of the positional information that leads to the proper localization of these proteins is unclear. In a screen for factors required for the localization of the Shigella sp. actin assembly protein IcsA to the bacterial pole, a mutant carrying a transposon insertion in mreB displayed altered targeting of IcsA. The phenotype of cells containing a transposon insertion in mreB was indistinguishable from that of cells containing a nonpolar mutation in mreB or that of wild-type cells treated with the MreB inhibitor A22. In cells lacking MreB, a green fluorescent protein (GFP) fusion to a cytoplasmic derivative of IcsA localized to multiple sites. Secreted full-length native IcsA was present in multiple faint patches on the surfaces of these cells in a pattern similar to that seen for the cytoplasmic IcsA-GFP fusion. EpsM, the polar Vibrio cholerae inner membrane protein, also localized to multiple sites in mreB cells and colocalized with IcsA, indicating that localization to multiple sites is not unique to IcsA. Our results are consistent with the requirement, either direct or indirect, for MreB in the restriction of certain polar material to defined sites within the cell and, in the absence of MreB, with the formation of ectopic sites containing polar material.
Collapse
Affiliation(s)
- Trine Nilsen
- Bacterial Pathogenesis Laboratories, University Park, 65 Landsdowne Street, Cambridge, MA 02139, USA
| | | | | | | |
Collapse
|
35
|
Shih YL, Kawagishi I, Rothfield L. The MreB and Min cytoskeletal-like systems play independent roles in prokaryotic polar differentiation. Mol Microbiol 2005; 58:917-28. [PMID: 16262780 DOI: 10.1111/j.1365-2958.2005.04841.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Establishment of an axis of cell polarity and differentiation of the cell poles are fundamental aspects of cellular development in many organisms. We compared the effects of two bacterial cytoskeletal-like systems, the MreB and MinCDE systems, on these processes in Escherichia coli. We report that the Min proteins are capable of establishing an axis of oscillation that is the initial step in establishment of polarity in spherical cells, in a process that is independent of the MreB cytoskeleton. In contrast, the MreB system is required for establishment of the rod shape of the cell and for polar targeting of other polar constituents, such as the Shigella virulence factor IcsA and the aspartate chemoreceptor Tar, in a process that is independent of the Min system. Thus, the two bacterial cytoskeletal-like systems act independently on different aspects of cell polarization.
Collapse
Affiliation(s)
- Yu-Ling Shih
- Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, CT 06032, USA.
| | | | | |
Collapse
|
36
|
Zhao J, Lambowitz AM. A bacterial group II intron-encoded reverse transcriptase localizes to cellular poles. Proc Natl Acad Sci U S A 2005; 102:16133-40. [PMID: 16186487 PMCID: PMC1283441 DOI: 10.1073/pnas.0507057102] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Lactococcus lactis Ll.LtrB group II intron encodes a reverse transcriptase (LtrA protein) that binds the intron RNA to promote RNA splicing and intron mobility. Here, we used LtrA-GFP fusions and immunofluorescence microscopy to show that LtrA localizes to cellular poles in Escherichia coli and Lactococcus lactis. This polar localization occurs with or without coexpression of Ll.LtrB intron RNA, is observed over a wide range of cellular growth rates and expression levels, and is independent of replication origin function. The same localization pattern was found for three nonoverlapping LtrA subsegments, possibly reflecting dependence on common redundant signals and/or protein physical properties. When coexpressed in E. coli, LtrA interferes with the polar localization of the Shigella IcsA protein, which mediates polarized actin tail assembly, suggesting competition for a common localization determinant. The polar localization of LtrA could account for the preferential insertion of the Ll.LtrB intron in the origin and terminus regions of the E. coli chromosome, may facilitate access to exposed DNA in these regions, and could potentially link group II intron mobility to the host DNA replication and/or cell division machinery.
Collapse
Affiliation(s)
- Junhua Zhao
- Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712, USA
| | | |
Collapse
|
37
|
Drew DA, Osborn MJ, Rothfield LI. A polymerization-depolymerization model that accurately generates the self-sustained oscillatory system involved in bacterial division site placement. Proc Natl Acad Sci U S A 2005; 102:6114-8. [PMID: 15840714 PMCID: PMC1087953 DOI: 10.1073/pnas.0502037102] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Determination of the proper site for division in Escherichia coli and other bacteria involves a unique spatial oscillatory system in which membrane-associated structures composed of the MinC, MinD and MinE proteins oscillate rapidly between the two cell poles. In vitro evidence indicates that this involves ordered cycles of assembly and disassembly of MinD polymers. We propose a mathematical model to explain this behavior. Unlike previous attempts, the present approach is based on the expected behavior of polymerization-depolymerization systems and incorporates current knowledge of the biochemical properties of MinD and MinE. Simulations based on the model reproduce all of the known topological and temporal characteristics of the in vivo oscillatory system.
Collapse
Affiliation(s)
- Donald A Drew
- Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA
| | | | | |
Collapse
|
38
|
Abstract
In rod-shaped bacteria, a surprisingly large number of proteins are localized to the cell poles. Polar positioning of proteins is crucial to many fundamental cellular processes. Formation of the pole occurs at the time of a prior cell division event and involves coordination of the cell division machinery with septal placement of newly-synthesized peptidoglycan. Development of polar peptidoglycan and outer membrane depends on the formation of the cytokinetic FtsZ ring at midcell. By contrast, positioning of at least two polar proteins depends on signals independent of both the assembly of the FtsZ ring and the synthesis of septal and polar peptidoglycan. We propose a model for distinct but interrelated developmental pathways for polar cell envelope synthesis and positional information recognized by polar proteins.
Collapse
Affiliation(s)
- Anuradha Janakiraman
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital/Harvard Medical School, 65 Landsdowne St., Cambridge, MA 02139, USA
| | | |
Collapse
|
39
|
Nilsen T, Ghosh AS, Goldberg MB, Young KD. Branching sites and morphological abnormalities behave as ectopic poles in shape-defective Escherichia coli. Mol Microbiol 2004; 52:1045-54. [PMID: 15130123 PMCID: PMC3097518 DOI: 10.1111/j.1365-2958.2004.04050.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Certain mutants in Escherichia coli lacking multiple penicillin-binding proteins (PBPs) produce misshapen cells containing kinks, bends and branches. These deformed regions exhibit two structural characteristics of normal cell poles: the peptidoglycan is inert to dilution by new synthesis or turnover, and a similarly stable patch of outer membrane caps the sites. To test the premise that these aberrant sites represent biochemically functional but misplaced cell poles, we assessed the intracellular distribution of proteins that localize specifically to bacterial poles. Green fluorescent protein (GFP) hybrids containing polar localization sequences from the Shigella flexneri IcsA protein or from the Vibrio cholerae EpsM protein formed foci at the poles of wild-type E. coli and at the poles and morphological abnormalities in PBP mutants. In addition, secreted wild-type IcsA localized to the outer membrane overlying these aberrant domains. We conclude that the morphologically deformed sites in these mutants represent fully functional poles or pole fragments. The results suggest that prokaryotic morphology is driven, at least in part, by the controlled placement of polar material, and that one or more of the low-molecular-weight PBPs participate in this process. Such mutants may help to unravel how particular proteins are targeted to bacterial poles, thereby creating important biochemical and functional asymmetries.
Collapse
Affiliation(s)
- Trine Nilsen
- Infectious Disease Division, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA
| | - Anindya S. Ghosh
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
| | - Marcia B. Goldberg
- Infectious Disease Division, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA
| | - Kevin D. Young
- Department of Microbiology and Immunology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA
- For correspondence. ; Tel. (+1) 701 777 2624; Fax (+1) 701 777 2054
| |
Collapse
|