scholarly journals Role of FtsEX in Cell Division of Escherichia coli: Viability of ftsEX Mutants Is Dependent on Functional SufI or High Osmotic Strength

2006 ◽  
Vol 189 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Manjula Reddy
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Salt Transport ◽  
High Osmolarity ◽  
Growth Defects ◽  
Ring Assembly ◽  
Multiple Copies ◽  
Z Ring ◽  
Twin Arginine Translocase ◽  
The Stability

ABSTRACT In Escherichia coli, at least 12 proteins, FtsZ, ZipA, FtsA, FtsE/X, FtsK, FtsQ, FtsL, FtsB, FtsW, FtsI, FtsN, and AmiC, are known to localize to the septal ring in an interdependent and sequential pathway to coordinate the septum formation at the midcell. The FtsEX complex is the latest recruit of this pathway, and unlike other division proteins, it is shown to be essential only on low-salt media. In this study, it is shown that ftsEX null mutations are not only salt remedial but also osmoremedial, which suggests that FtsEX may not be involved in salt transport as previously thought. Increased coexpression of cell division proteins FtsQ-FtsA-FtsZ or FtsN alone restored the growth defects of ftsEX mutants. ftsEX deletion exacerbated the defects of most of the mutants affected in Z ring localization and septal assembly; however, the ftsZ84 allele was a weak suppressor of ftsEX. The viability of ftsEX mutants in high-osmolarity conditions was shown to be dependent on the presence of a periplasmic protein, SufI, a substrate of twin-arginine translocase. In addition, SufI in multiple copies could substitute for the functions of FtsEX. Taken together, these results suggest that FtsE and FtsX are absolutely required for the process of cell division in conditions of low osmotic strength for the stability of the septal ring assembly and that, during high-osmolarity conditions, the FtsEX and SufI functions are redundant for this essential process.

scholarly journals A newly identified prophage-encoded gene, ymfM, causes SOS-inducible filamentation in Escherichia coli

2021 ◽  
Author(s):  
Shirin Ansari ◽  
James C. Walsh ◽  
Amy L. Bottomley ◽  
Iain G. Duggin ◽  
Catherine Burke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Ring Assembly ◽  
Multiple Alternative ◽  
Z Ring ◽  
Cell Division Inhibitor

Rod-shaped bacteria such as Escherichia coli can regulate cell division in response to stress, leading to filamentation, a process where cell growth and DNA replication continues in the absence of division, resulting in elongated cells. The classic example of stress is DNA damage which results in the activation of the SOS response. While the inhibition of cell division during SOS has traditionally been attributed to SulA in E. coli, a previous report suggests that the e14 prophage may also encode an SOS-inducible cell division inhibitor, previously named SfiC. However, the exact gene responsible for this division inhibition has remained unknown for over 35 years. A recent high-throughput over-expression screen in E. coli identified the e14 prophage gene, ymfM, as a potential cell division inhibitor. In this study, we show that the inducible expression of ymfM from a plasmid causes filamentation. We show that this expression of ymfM results in the inhibition of Z ring formation and is independent of the well characterised inhibitors of FtsZ ring assembly in E. coli, SulA, SlmA and MinC. We confirm that ymfM is the gene responsible for the SfiC phenotype as it contributes to the filamentation observed during the SOS response. This function is independent of SulA, highlighting that multiple alternative division inhibition pathways exist during the SOS response. Our data also highlight that our current understanding of cell division regulation during the SOS response is incomplete and raises many questions regarding how many inhibitors there actually are and their purpose for the survival of the organism. Importance: Filamentation is an important biological mechanism which aids in the survival, pathogenesis and antibiotic resistance of bacteria within different environments, including pathogenic bacteria such as uropathogenic Escherichia coli. Here we have identified a bacteriophage-encoded cell division inhibitor which contributes to the filamentation that occurs during the SOS response. Our work highlights that there are multiple pathways that inhibit cell division during stress. Identifying and characterising these pathways is a critical step in understanding survival tactics of bacteria which become important when combating the development of bacterial resistance to antibiotics and their pathogenicity.

scholarly journals Analysis of MinC Reveals Two Independent Domains Involved in Interaction with MinD and FtsZ

2000 ◽  
Vol 182 (14) ◽  
pp. 3965-3971 ◽  
Author(s):  
Zonglin Hu ◽  
Joe Lutkenhaus
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Functional Domains ◽  
Wild Type ◽  
Terminal Domain ◽  
Ring Assembly ◽  
Z Ring ◽  
Ftsz Assembly

ABSTRACT In Escherichia coli FtsZ assembles into a Z ring at midcell while assembly at polar sites is prevented by themin system. MinC, a component of this system, is an inhibitor of FtsZ assembly that is positioned within the cell by interaction with MinDE. In this study we found that MinC consists of two functional domains connected by a short linker. When fused to MalE the N-terminal domain is able to inhibit cell division and prevent FtsZ assembly in vitro. The C-terminal domain interacts with MinD, and expression in wild-type cells as a MalE fusion disrupts minfunction, resulting in a minicell phenotype. We also find that MinC is an oligomer, probably a dimer. Although the C-terminal domain is clearly sufficient for oligomerization, the N-terminal domain also promotes oligomerization. These results demonstrate that MinC consists of two independently functioning domains: an N-terminal domain capable of inhibiting FtsZ assembly and a C-terminal domain responsible for localization of MinC through interaction with MinD. The fusion of these two independent domains is required to achieve topological regulation of Z ring assembly.

scholarly journals The C-Terminal Domain of MinC Inhibits Assembly of the Z Ring in Escherichia coli

2006 ◽  
Vol 189 (1) ◽  
pp. 236-243 ◽  
Author(s):  
Daisuke Shiomi ◽  
William Margolin
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Fluorescent Protein ◽  
Additional Function ◽  
Ring Assembly ◽  
C Terminus ◽  
Min Proteins ◽  
Z Ring ◽  
Ftsz Assembly ◽  
Green Fluorescent

ABSTRACT In Escherichia coli, the Min system, consisting of three proteins, MinC, MinD, and MinE, negatively regulates FtsZ assembly at the cell poles, helping to ensure that the Z ring will assemble only at midcell. Of the three Min proteins, MinC is sufficient to inhibit Z-ring assembly. By binding to MinD, which is mostly localized at the membrane near the cell poles, MinC is sequestered away from the cell midpoint, increasing the probability of Z-ring assembly there. Previously, it has been shown that the two halves of MinC have two distinct functions. The N-terminal half is sufficient for inhibition of FtsZ assembly, whereas the C-terminal half of the protein is required for binding to MinD as well as to a component of the division septum. In this study, we discovered that overproduction of the C-terminal half of MinC (MinC122-231) could also inhibit cell division and that this inhibition was at the level of Z-ring disassembly and dependent on MinD. We also found that fusing green fluorescent protein to either the N-terminal end of MinC122-231, the C terminus of full-length MinC, or the C terminus of MinC122-231 perturbed MinC function, which may explain why cell division inhibition by MinC122-231 was not detected previously. These results suggest that the C-terminal half of MinC has an additional function in the regulation of Z-ring assembly.

scholarly journals A newly identified prophage-encoded gene, ymfM, causes SOS-inducible filamentation in Escherichia coli

2020 ◽  
Author(s):  
Shirin Ansari ◽  
James C. Walsh ◽  
Amy L. Bottomley ◽  
Iain G. Duggin ◽  
Catherine Burke ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Pathogenic Bacteria ◽  
Bacterial Resistance ◽  
Sos Response ◽  
E Coli ◽  
Ring Assembly ◽  
Z Ring ◽  
Response To Stress ◽  
Cell Division Inhibitor

AbstractRod-shaped bacteria such as Escherichia coli can regulate cell division in response to stress, leading to filamentation, a process where cell growth and DNA replication continues in the absence of division, resulting in elongated cells. The classic example of stress is DNA damage which results in the activation of the SOS response. While the inhibition of cell division during SOS has traditionally been attributed to SulA in E. coli, a previous report suggests that the e14 prophage may also encode an SOS-inducible cell division inhibitor, previously named SfiC. However, the exact gene responsible for this division inhibition has remained unknown for over 35 years. A recent high-throughput over-expression screen in E. coli identified the e14 prophage gene, ymfM, as a potential cell division inhibitor. In this study, we show that the inducible expression of ymfM from a plasmid causes filamentation. We show that this expression of ymfM results in the inhibition of Z ring formation and is independent of the well characterised inhibitors of FtsZ ring assembly in E. coli, SulA, SlmA and MinC. We confirm that ymfM is the gene responsible for the SfiC+ phenotype as it contributes to the filamentation observed during the SOS response. This function is independent of SulA, highlighting that multiple division inhibition pathways exist during the stress-induced SOS response. Our data also highlight that our current understanding of cell division regulation during the SOS response is incomplete and raises many questions regarding how many inhibitors there actually are and their purpose for the survival of the organism.ImportanceFilamentation is an important biological mechanism which aids in the survival, pathogenesis and antibiotic resistance of bacteria within different environments, including pathogenic bacteria such as uropathogenic Escherichia coli. Here we have identified a bacteriophage-encoded cell division inhibitor which contributes to the filamentation that occurs during the SOS response. Our work highlights that there are multiple pathways that inhibit cell division during stress. Identifying and characterising these pathways is a critical step in understanding survival tactics of bacteria which become important when combating the development of bacterial resistance to antibiotics and their pathogenicity.

scholarly journals Escherichia coli Division Inhibitor MinCD Blocks Septation by Preventing Z-Ring Formation

2001 ◽  
Vol 183 (22) ◽  
pp. 6630-6635 ◽  
Author(s):  
Sebastien Pichoff ◽  
Joe Lutkenhaus
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Direct Interaction ◽  
Ring Formation ◽  
Ring Assembly ◽  
Z Ring ◽  
Alternative Fixation ◽  
Green Fluorescent

ABSTRACT The min system spatially regulates division through the topological regulation of MinCD, an inhibitor of cell division. MinCD was previously shown to inhibit division by preventing assembly of the Z ring (E. Bi and J. Lutkenhaus, J. Bacteriol. 175:1118–1125, 1993); however, this was questioned in a recent report (S. S. Justice, J. Garcia-Lara, and L. I. Rothfield, Mol. Microbiol. 37:410–423, 2000) which indicated that MinCD acted after Z-ring formation and prevented the recruitment of FtsA to the Z ring. This discrepancy was due in part to alternative fixation conditions. We have therefore reinvestigated the action of MinCD and avoided fixation by using green fluorescent protein (GFP) fusions to division proteins. MinCD prevented the localization of both FtsZ-GFP and ZipA-GFP, consistent with it preventing Z-ring assembly. Consistent with a direct interaction between FtsZ and the MinCD inhibitor, we find that increased FtsZ, but not FtsA, suppresses MinCD-induced lethality. Furthermore, strains carrying various alleles offtsZ, selected on the basis of resistance to the inhibitor SulA, displayed variable resistance to MinCD. These results are consistent with FtsZ as the target of MinCD and confirm that this inhibitor prevents Z-ring assembly.

scholarly journals Role of SufI (FtsP) in Cell Division of Escherichia coli: Evidence for Its Involvement in Stabilizing the Assembly of the Divisome

2007 ◽  
Vol 189 (22) ◽  
pp. 8044-8052 ◽  
Author(s):  
Harish Samaluru ◽  
L. SaiSree ◽  
Manjula Reddy
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Dna Damage ◽  
Cell Division ◽  
Suppressor Gene ◽  
Lethal Mutant ◽  
Synthetic Lethal ◽  
Multicopy Suppressor ◽  
Ring Assembly ◽  
Multiple Copies

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 ΔftsEX 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.

scholarly journals Deletion of the min Operon Results in Increased Thermosensitivity of an ftsZ84 Mutant and Abnormal FtsZ Ring Assembly, Placement, and Disassembly

2000 ◽  
Vol 182 (21) ◽  
pp. 6203-6213 ◽  
Author(s):  
Xuan-Chuan Yu ◽  
William Margolin
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
High Frequency ◽  
Double Mutant ◽  
Nonpermissive Temperature ◽  
Ftsz Ring ◽  
Single Mutant ◽  
Ring Assembly ◽  
Z Ring ◽  
Thermosensitive Mutation

ABSTRACT To investigate the interaction between FtsZ and the Min system during cell division of Escherichia coli, we examined the effects of combining a well-known thermosensitive mutation offtsZ, ftsZ84, with ΔminCDE, a deletion of the entire min locus. Because the Min system is thought to down-regulate Z-ring assembly, the prediction was that removing minCDE might at least partially suppress the thermosensitivity of ftsZ84, which can form colonies below 42°C but not at or above 42°C. Contrary to expectations, the double mutant was significantly more thermosensitive than theftsZ84 single mutant. When shifted to the new lower nonpermissive temperature, the double mutant formed long filaments mostly devoid of Z rings, suggesting a likely cause of the increased thermosensitivity. Interestingly, even at 22°C, many Z rings were missing in the double mutant, and the rings that were present were predominantly at the cell poles. Of these, a large number were present only at one pole. These cells exhibited a higher than expected incidence of polar divisions, with a bias toward the newest pole. Moreover, some cells exhibited dramatically elongated septa that stained for FtsZ, suggesting that the double mutant is defective in Z-ring disassembly, and providing a possible mechanism for the polar bias. Thermoresistant suppressors of the double mutant arose that had modestly increased levels of FtsZ84. These cells also exhibited elongated septa and, in addition, produced a high frequency of branched cells. A thermoresistant suppressor of the ftsZ84 single mutant also synthesized more FtsZ84 and produced branched cells. The evidence from this study indicates that removing the Min system exposes and exacerbates the inherent defects of the FtsZ84 protein, resulting in clear septation phenotypes even at low growth temperatures. Increasing levels of FtsZ84 can suppress some, but not all, of these phenotypes.

scholarly journals High-resolution crystal structures of Escherichia coli FtsZ bound to GDP and GTP

2020 ◽  
Vol 76 (2) ◽  
pp. 94-102 ◽  
Author(s):  
Maria A. Schumacher ◽  
Tomoo Ohashi ◽  
Lauren Corbin ◽  
Harold P. Erickson
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Cell Division ◽  
High Resolution ◽  
Crystal Structures ◽  
Bacterial Cell ◽  
Model System ◽  
E Coli ◽  
Z Ring ◽  
Main Model

Bacterial cytokinesis is mediated by the Z-ring, which is formed by the prokaryotic tubulin homolog FtsZ. Recent data indicate that the Z-ring is composed of small patches of FtsZ protofilaments that travel around the bacterial cell by treadmilling. Treadmilling involves a switch from a relaxed (R) state, favored for monomers, to a tense (T) conformation, which is favored upon association into filaments. The R conformation has been observed in numerous monomeric FtsZ crystal structures and the T conformation in Staphylococcus aureus FtsZ crystallized as assembled filaments. However, while Escherichia coli has served as a main model system for the study of the Z-ring and the associated divisome, a structure has not yet been reported for E. coli FtsZ. To address this gap, structures were determined of the E. coli FtsZ mutant FtsZ(L178E) with GDP and GTP bound to 1.35 and 1.40 Å resolution, respectively. The E. coli FtsZ(L178E) structures both crystallized as straight filaments with subunits in the R conformation. These high-resolution structures can be employed to facilitate experimental cell-division studies and their interpretation in E. coli.

scholarly journals MinC, MinD, and MinE Drive Counter-oscillation of Early-Cell-Division Proteins Prior to Escherichia coli Septum Formation

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Paola Bisicchia ◽  
Senthil Arumugam ◽  
Petra Schwille ◽  
David Sherratt
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Lipid Bilayers ◽  
Epifluorescence Microscopy ◽  
Bacterial Cell Division ◽  
Content Type ◽  
Septum Formation ◽  
Early Stages ◽  
Z Ring ◽  
High Concentrations

ABSTRACTBacterial cell division initiates with the formation of a ring-like structure at the cell center composed of the tubulin homolog FtsZ (the Z-ring), which acts as a scaffold for the assembly of the cell division complex, the divisome. Previous studies have suggested that the divisome is initially composed of FtsZ polymers stabilized by membrane anchors FtsA and ZipA, which then recruit the remaining division proteins. The MinCDE proteins prevent the formation of the Z-ring at poles by oscillating from pole to pole, thereby ensuring that the concentration of the Z-ring inhibitor, MinC, is lowest at the cell center. We show that prior to septum formation, the early-division proteins ZipA, ZapA, and ZapB, along with FtsZ, assemble into complexes that counter-oscillate with respect to MinC, and with the same period. We propose that FtsZ molecules distal from high concentrations of MinC form relatively slowly diffusing filaments that are bound by ZapAB and targeted to the inner membrane by ZipA or FtsA. These complexes may facilitate the early stages of divisome assembly at midcell. As MinC oscillates toward these complexes, FtsZ oligomerization and bundling are inhibited, leading to shorter or monomeric FtsZ complexes, which become less visible by epifluorescence microscopy because of their rapid diffusion. Reconstitution of FtsZ-Min waves on lipid bilayers shows that FtsZ bundles partition away from high concentrations of MinC and that ZapA appears to protect FtsZ from MinC by inhibiting FtsZ turnover.IMPORTANCEA big issue in biology for the past 100 years has been that of how a cell finds its middle. InEscherichia coli, over 20 proteins assemble at the cell center at the time of division. We show that the MinCDE proteins, which prevent the formation of septa at the cell pole by inhibiting FtsZ, drive the counter-oscillation of early-cell-division proteins ZapA, ZapB, and ZipA, along with FtsZ. We propose that FtsZ forms filaments at the pole where the MinC concentration is the lowest and acts as a scaffold for binding of ZapA, ZapB, and ZipA: such complexes are disassembled by MinC and reform within the MinC oscillation period before accumulating at the cell center at the time of division. The ability of FtsZ to be targeted to the cell center in the form of oligomers bound by ZipA and ZapAB may facilitate the early stages of divisome assembly.

scholarly journals Modes of Overinitiation, dnaA Gene Expression, and Inhibition of Cell Division in a Novel Cold-Sensitive hda Mutant of Escherichia coli

2008 ◽  
Vol 190 (15) ◽  
pp. 5368-5381 ◽  
Author(s):  
Kazuyuki Fujimitsu ◽  
Masayuki Su'etsugu ◽  
Yoko Yamaguchi ◽  
Kensaku Mazda ◽  
Nisi Fu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Cell Cycle Progression ◽  
Synthetic Lethality ◽  
Active Form ◽  
Dependent Manner ◽  
Chromosomal Replication ◽  
Independent Manner ◽  
Multiple Copies ◽  
Cold Sensitive

ABSTRACT The chromosomal replication cycle is strictly coordinated with cell cycle progression in Escherichia coli. ATP-DnaA initiates replication, leading to loading of the DNA polymerase III holoenzyme. The DNA-loaded form of the β clamp subunit of the polymerase binds the Hda protein, which promotes ATP-DnaA hydrolysis, yielding inactive ADP-DnaA. This regulation is required to repress overinitiation. In this study, we have isolated a novel cold-sensitive hda mutant, the hda-185 mutant. The hda-185 mutant caused overinitiation of chromosomal replication at 25°C, which most likely led to blockage of replication fork progress. Consistently, the inhibition of colony formation at 25°C was suppressed by disruption of the diaA gene, an initiation stimulator. Disruption of the seqA gene, an initiation inhibitor, showed synthetic lethality with hda-185 even at 42°C. The cellular ATP-DnaA level was increased in an hda-185-dependent manner. The cellular concentrations of DnaA protein and dnaA mRNA were comparable at 25°C to those in a wild-type hda strain. We also found that multiple copies of the ribonucleotide reductase genes (nrdAB or nrdEF) or dnaB gene repressed overinitiation. The cellular levels of dATP and dCTP were elevated in cells bearing multiple copies of nrdAB. The catalytic site within NrdA was required for multicopy suppression, suggesting the importance of an active form of NrdA or elevated levels of deoxyribonucleotides in inhibition of overinitiation in the hda-185 cells. Cell division in the hda-185 mutant was inhibited at 25°C in a LexA regulon-independent manner, suggesting that overinitiation in the hda-185 mutant induced a unique division inhibition pathway.

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