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Auer GK, Lee TK, Rajendram M, Cesar S, Miguel A, Huang KC, Weibel DB. Mechanical Genomics Identifies Diverse Modulators of Bacterial Cell Stiffness. Cell Syst 2016; 2:402-11. [PMID: 27321372 PMCID: PMC4967499 DOI: 10.1016/j.cels.2016.05.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 02/03/2016] [Accepted: 05/18/2016] [Indexed: 10/21/2022]
Abstract
Bacteria must maintain mechanical integrity to withstand the large osmotic pressure differential across the cell membrane and wall. Although maintaining mechanical integrity is critical for proper cellular function, a fact exploited by prominent cell-wall-targeting antibiotics, the proteins that contribute to cellular mechanics remain unidentified. Here, we describe a high-throughput optical method for quantifying cell stiffness and apply this technique to a genome-wide collection of ∼4,000 Escherichia coli mutants. We identify genes with roles in diverse functional processes spanning cell-wall synthesis, energy production, and DNA replication and repair that significantly change cell stiffness when deleted. We observe that proteins with biochemically redundant roles in cell-wall synthesis exhibit different stiffness defects when deleted. Correlating our data with chemical screens reveals that reducing membrane potential generally increases cell stiffness. In total, our work demonstrates that bacterial cell stiffness is a property of both the cell wall and broader cell physiology and lays the groundwork for future systematic studies of mechanoregulation.
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Affiliation(s)
- George K Auer
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Timothy K Lee
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Manohary Rajendram
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Spencer Cesar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amanda Miguel
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Douglas B Weibel
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Murakami J, Terao Y, Morisaki I, Hamada S, Kawabata S. Group A streptococcus adheres to pharyngeal epithelial cells with salivary proline-rich proteins via GrpE chaperone protein. J Biol Chem 2012; 287:22266-75. [PMID: 22566698 DOI: 10.1074/jbc.m112.350082] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Group A Streptococcus pyogenes (GAS) is an important human pathogen that frequently causes pharyngitis. GAS organisms can adhere to and invade pharyngeal epithelial cells, which are overlaid by salivary components. However, the role of salivary components in GAS adhesion to pharyngeal cells has not been reported precisely. We collected human saliva and purified various salivary components, including proline-rich protein (PRP), statherin, and amylase, and performed invasion assays. The GAS-HEp-2 association ratio (invasion/adhesion ratio) and invasion ratio of GAS were increased significantly with whole human saliva and PRP, while the anti-PRP antibody inhibited the latter. GAS strain NY-5, which lacks M and F proteins on the cell surface, was promoted to cohere with HEp-2 cells by whole human saliva and PRP. The 28-kDa protein of GAS bound to PRP and was identified as GrpE, a chaperone protein, whereas the N-terminal of GrpE was found to bind to PRP. A GrpE-deficient mutant of GAS strain B514Sm, TR-45, exhibited a reduced ability to adhere to and invade HEp-2 cells. Microscopic observations showed the GrpE was mainly expressed on the surface of the cell division site of GAS. Furthermore, GrpE-deficient mutants of GAS and Streptococcus pneumoniae showed an elongated morphology as compared with the wild type. Taken together, this is the first study to show an interaction between salivary PRP and GAS GrpE, which plays an important role in GAS infection on the pharynx, whereas the expression of GrpE on the surface of GAS helps to maintain morphology.
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Affiliation(s)
- Jumpei Murakami
- Division of Special Care Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, 565-0871, Japan
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Abstract
Mutations at the APM1 and APM2 loci in the green alga Chlamydomonas reinhardtii confer resistance to phosphorothioamidate and dinitroaniline herbicides. Genetic interactions between apm1 and apm2 mutations suggest an interaction between the gene products. We identified the APM1 and APM2 genes using a map-based cloning strategy. Genomic DNA fragments containing only the DNJ1 gene encoding a type I Hsp40 protein rescue apm1 mutant phenotypes, conferring sensitivity to the herbicides and rescuing a temperature-sensitive growth defect. Lesions at five apm1 alleles include missense mutations and nucleotide insertions and deletions that result in altered proteins or very low levels of gene expression. The HSP70A gene, encoding a cytosolic Hsp70 protein known to interact with Hsp40 proteins, maps near the APM2 locus. Missense mutations found in three apm2 alleles predict altered Hsp70 proteins. Genomic fragments containing the HSP70A gene rescue apm2 mutant phenotypes. The results suggest that a client of the Hsp70-Hsp40 chaperone complex may function to increase microtubule dynamics in Chlamydomonas cells. Failure of the chaperone system to recognize or fold the client protein(s) results in increased microtubule stability and resistance to the microtubule-destabilizing effect of the herbicides. The lack of redundancy of genes encoding cytosolic Hsp70 and Hsp40 type I proteins in Chlamydomonas makes it a uniquely valuable system for genetic analysis of the function of the Hsp70 chaperone complex.
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The proper ratio of GrpE to DnaK is important for protein quality control by the DnaK–DnaJ–GrpE chaperone system and for cell division. Microbiology (Reading) 2008; 154:1876-1885. [DOI: 10.1099/mic.0.2008/017376-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Abstract
Plastids are derived from free-living cyanobacteria that were engulfed by eukaryotic host cells through the process of endosymbiosis and, like their cyanobacterial ancestors, divide by binary fission. Over the last decade the continued identification and functional analysis of plastid division components, coupled with ever-increasing genomic resources, have yielded insights into the origins and evolution of the plastid division mechanism in higher plants. Here we review the current understanding of the evolution of the chloroplast division proteins and present a model of how the machinery has developed to execute plastid division in Arabidopsis.
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Affiliation(s)
- Astrid E Tveitaskog
- Centre for Organelle Research, Department of Mathematics and Natural Science, University of Stavanger, N-4036 Stavanger, Norway
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Samaluru H, SaiSree L, Reddy M. Role of SufI (FtsP) in cell division of Escherichia coli: evidence for its involvement in stabilizing the assembly of the divisome. J Bacteriol 2007; 189:8044-52. [PMID: 17766410 PMCID: PMC2168700 DOI: 10.1128/jb.00773-07] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The function of SufI, a well-studied substrate of the TatABC translocase in Escherichia coli, is not known. It was earlier implicated in cell division, based on the finding that multiple copies of sufI suppressed the phenotypes of cells with mutations in ftsI (ftsI23), which encodes a divisomal transpeptidase. Recently, sufI was identified as both a multicopy suppressor gene and a synthetic lethal mutant of ftsEX, which codes for a division-specific putative ABC transporter. In this study, we show that sufI is essential for the viability of E. coli cells subjected to various forms of stress, including oxidative stress and DNA damage. The sufI mutant also exhibits sulA-independent filamentation, indicating a role in cell division. The phenotypes of the sufI mutant are suppressed by factors that stabilize FtsZ ring assembly, such as increased expression of cell division proteins FtsQAZ or FtsN or the presence of the gain-of-function ftsA* (FtsA R286W) mutation, suggesting that SufI is a divisomal protein required during stress conditions. In support of this, multicopy sufI suppressed the divisional defects of mutants carrying the ftsA12, ftsQ1, or ftsK44 allele but not those of mutants carrying ftsZ84. Most of the division-defective mutants, in particular those carrying a DeltaftsEX or ftsI23 allele, exhibited sensitivity to oxidative stress or DNA damage, and this sensitivity was also abolished by multiple copies of SufI. All of these data suggest that SufI is a division component involved in protecting or stabilizing the divisomal assembly under conditions of stress. Since sufI fulfils the requirements to be designated an fts gene, we propose that it be renamed ftsP.
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Affiliation(s)
- Harish Samaluru
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
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Maple J, Møller SG. Plastid division coordination across a double-membraned structure. FEBS Lett 2007; 581:2162-7. [PMID: 17350001 DOI: 10.1016/j.febslet.2007.02.062] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2006] [Revised: 02/19/2007] [Accepted: 02/26/2007] [Indexed: 11/16/2022]
Abstract
Chloroplasts still retain components of the bacterial cell division machinery and research over the past decade has led to an understanding of how these stromal division proteins assemble and function as a complex chloroplast division machinery. However, during evolution plant chloroplasts have acquired a number of cytosolic division proteins, indicating that unlike the cyanobacterial ancestors of plastids, chloroplast division in higher plants require a second division machinery located on the chloroplast outer envelope membrane. Here we review the current understanding of the stromal and cytosolic plastid division machineries and speculate how two protein machineries coordinate their activities across a double-membraned structure.
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Affiliation(s)
- Jodi Maple
- Centre for Organelle Research, Department of Mathematics and Natural Sciences, University of Stavanger, N-4036 Stavanger, Norway
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Vicente M, Rico AI, Martínez-Arteaga R, Mingorance J. Septum enlightenment: assembly of bacterial division proteins. J Bacteriol 2006; 188:19-27. [PMID: 16352817 PMCID: PMC1317574 DOI: 10.1128/jb.188.1.19-27.2006] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Miguel Vicente
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, c/ Darwin 3, 28049 Madrid, Spain.
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Maple J, Møller SG. An emerging picture of plastid division in higher plants. PLANTA 2005; 223:1-4. [PMID: 16136332 DOI: 10.1007/s00425-005-0078-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 06/30/2005] [Indexed: 05/04/2023]
Affiliation(s)
- Jodi Maple
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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Maple J, Aldridge C, Møller SG. Plastid division is mediated by combinatorial assembly of plastid division proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 43:811-23. [PMID: 16146521 DOI: 10.1111/j.1365-313x.2005.02493.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plastids arise by division from pre-existing organelles, and with the recent characterization of several new components of plastid division our understanding of the division process in higher plants has improved dramatically. However, it is still not known how these different protein components act together during division. Here we analyse protein-protein interactions between all known stromal plastid division proteins. Using a combination of quantitative yeast two-hybrid assays, in planta co-localization studies, fluorescence resonance energy transfer and bimolecular fluorescence complementation assays we show that these proteins do not act in isolation but rather in protein complexes to govern appropriate plastid division. We have previously shown that AtMinD1 forms functional homodimers and we show here that in addition to homodimerization AtMinD1 also interacts with AtMinE1. Furthermore, AtMinE1 has the ability to homodimerize. We also demonstrate that proteins from both FtsZ families (AtFtsZ1-1 and AtFtsZ2-1) not only interact with themselves but also with each other, and we show that these interactions are not dependent on correct Z-ring formation. Further to this we demonstrate that ARC6 specifically interacts with the core domain of AtFtsZ2-1, but not with AtFtsZ1-1, providing in planta evidence for a functional difference between the two FtsZ protein families in plants. Our studies have enabled us to construct a meaningful intraplastidic protein-protein interaction map of all known stromal plastid division proteins in Arabidopsis.
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Affiliation(s)
- Jodi Maple
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
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Vitha S, Froehlich JE, Koksharova O, Pyke KA, van Erp H, Osteryoung KW. ARC6 is a J-domain plastid division protein and an evolutionary descendant of the cyanobacterial cell division protein Ftn2. THE PLANT CELL 2003; 15:1918-33. [PMID: 12897262 PMCID: PMC167179 DOI: 10.1105/tpc.013292] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2003] [Accepted: 05/21/2003] [Indexed: 05/18/2023]
Abstract
Replication of chloroplasts is essential for achieving and maintaining optimal plastid numbers in plant cells. The plastid division machinery contains components of both endosymbiotic and host cell origin, but little is known about the regulation and molecular mechanisms that govern the division process. The Arabidopsis mutant arc6 is defective in plastid division, and its leaf mesophyll cells contain only one or two grossly enlarged chloroplasts. We show here that arc6 chloroplasts also exhibit abnormal localization of the key plastid division proteins FtsZ1 and FtsZ2. Whereas in wild-type plants, the FtsZ proteins assemble into a ring at the plastid division site, chloroplasts in the arc6 mutant contain numerous short, disorganized FtsZ filament fragments. We identified the mutation in arc6 and show that the ARC6 gene encodes a chloroplast-targeted DnaJ-like protein localized to the plastid envelope membrane. An ARC6-green fluorescent protein fusion protein was localized to a ring at the center of the chloroplasts and rescued the chloroplast division defect in the arc6 mutant. The ARC6 gene product is related closely to Ftn2, a prokaryotic cell division protein unique to cyanobacteria. Based on the FtsZ filament morphology observed in the arc6 mutant and in plants that overexpress ARC6, we hypothesize that ARC6 functions in the assembly and/or stabilization of the plastid-dividing FtsZ ring. We also analyzed FtsZ localization patterns in transgenic plants in which plastid division was blocked by altered expression of the division site-determining factor AtMinD. Our results indicate that MinD and ARC6 act in opposite directions: ARC6 promotes and MinD inhibits FtsZ filament formation in the chloroplast.
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Affiliation(s)
- Stanislav Vitha
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
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Andreu JM, Oliva MA, Monasterio O. Reversible unfolding of FtsZ cell division proteins from archaea and bacteria. Comparison with eukaryotic tubulin folding and assembly. J Biol Chem 2002; 277:43262-70. [PMID: 12215443 DOI: 10.1074/jbc.m206723200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The stability, refolding, and assembly properties of FtsZ cell division proteins from Methanococcus jannaschii and Escherichia coli have been investigated. Their guanidinium chloride unfolding has been studied by circular dichroism spectroscopy. FtsZ from E. coli and tubulin released the bound guanine nucleotide, coinciding with an initial unfolding stage at low denaturant concentrations, followed by unfolding of the apoprotein. FtsZ from M. jannaschii released its nucleotide without any detectable secondary structural change. It unfolded in an apparently two-state transition at larger denaturant concentrations. Isolated FtsZ polypeptide chains were capable of spontaneous refolding and GTP-dependent assembly. The homologous eukaryotic tubulin monomers misfold in solution, but fold within the cytosolic chaperonin CCT. Analysis of the extensive tubulin loop insertions in the FtsZ/tubulin common core and of the intermolecular contacts in model microtubules and tubulin-CCT complexes shows a loop insertion present at every element of lateral protofilament contact and at every contact of tubulin with CCT (except at loop T7). The polymers formed by purified FtsZ have a distinct limited protofilament association in comparison with microtubules. We propose that the loop insertions of tubulin and its CCT-assisted folding coevolved with the lateral association interfaces responsible for extended two-dimensional polymerization into microtubule polymers.
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Affiliation(s)
- Jose Manuel Andreu
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, Velázquez 144, 28006 Madrid, Spain.
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Ichimura T, Yamazoe M, Maeda M, Wada C, Hiraga S. Proteolytic activity of YibP protein in Escherichia coli. J Bacteriol 2002; 184:2595-602. [PMID: 11976287 PMCID: PMC135028 DOI: 10.1128/jb.184.10.2595-2602.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli YibP protein (47.4 kDa) has a membrane-spanning signal at the N-terminal region, two long coiled-coil regions in the middle part, and a C-terminal globular domain, which involves amino acid sequences homologous to the peptidase M23/M37 family. A yibP disrupted mutant grows in rich medium at 37 degrees C but not at 42 degrees C. In the yibP null mutant, cell division and FtsZ ring formation are inhibited at 42 degrees C without SOS induction, resulting in filamentous cells with multiple nucleoids and finally in cell lysis. Five percent betaine suppresses the temperature sensitivity of the yibP disrupted mutation. The mutant has the same sensitivity to drugs, such as nalidixic acid, ethidium bromide, ethylmethane sulfonate, and sodium dodecyl sulfate, as the parental strain. YibP protein is recovered in the inner membrane and cytoplasmic fractions, but not in the outer membrane fraction. Results suggest that the coiled-coil regions and the C-terminal globular domain of YibP are localized in the cytoplasmic space, not in the periplasmic space. Purified YibP has a protease activity that split the substrate beta-casein.
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Affiliation(s)
- Toshiharu Ichimura
- Division of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kuhonji 4-24-1, Kumamoto 862-0976, Japan
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