scholarly journals Timing of FtsZ Assembly in Escherichia coli

1999 ◽  
Vol 181 (17) ◽  
pp. 5167-5175 ◽  
Author(s):  
Tanneke Den Blaauwen ◽  
Nienke Buddelmeijer ◽  
Mirjam E. G. Aarsman ◽  
Cor M. Hameete ◽  
Nanne Nanninga
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Dna Replication ◽  
Growth Conditions ◽  
Ftsz Ring ◽  
Contrast Microscopy ◽  
Z Ring ◽  
Ftsz Assembly ◽  
K 12

ABSTRACT The timing of the appearance of the FtsZ ring at the future site of division in Escherichia coli was determined by in situ immunofluorescence microscopy for two strains grown under steady-state conditions. The strains, B/rA and K-12 MC4100, differ largely in the duration of the D period, the time between termination of DNA replication and cell division. In both strains and under various growth conditions, the assembly of the FtsZ ring was initiated approximately simultaneously with the start of the D period. This is well before nucleoid separation or initiation of constriction as determined by fluorescence and phase-contrast microscopy. The durations of the Z-ring period, the D period, and the period with a visible constriction seem to be correlated under all investigated growth conditions in these strains. These results suggest that (near) termination of DNA replication could provide a signal that initiates the process of cell division.

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 MinC N- and C-Domain Interactions Modulate FtsZ Assembly, Division Site Selection, and MinD-Dependent Oscillation inEscherichia coli

2018 ◽  
Vol 201 (4) ◽  
Author(s):  
Christopher J. LaBreck ◽  
Joseph Conti ◽  
Marissa G. Viola ◽  
Jodi L. Camberg
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Site Selection ◽  
Fluorescent Protein ◽  
Site Mutation ◽  
Content Type ◽  
Ftsz Ring ◽  
Division Site ◽  
Z Ring

ABSTRACTThe Min system inEscherichia coli, consisting of MinC, MinD, and MinE proteins, regulates division site selection by preventing assembly of the FtsZ-ring (Z-ring) and exhibits polar oscillationin vivo. MinC antagonizes FtsZ polymerization, andin vivo, the cellular location of MinC is controlled by a direct association with MinD at the membrane. To further understand the interactions of MinC with FtsZ and MinD, we performed a mutagenesis screen to identify substitutions inminCthat are associated with defects in cell division. We identified amino acids in both the N- and C-domains of MinC that are important for direct interactions with FtsZ and MinDin vitro, as well as mutations that modify the observedin vivooscillation of green fluorescent protein (GFP)-MinC. Our results indicate that there are two distinct surface-exposed sites on MinC that are important for direct interactions with FtsZ, one at a cleft on the surface of the N-domain and a second on the C-domain that is adjacent to the MinD interaction site. Mutation of either of these sites leads to slower oscillation of GFP-MinCin vivo, although the MinC mutant proteins are still capable of a direct interaction with MinD in phospholipid recruitment assays. Furthermore, we demonstrate that interactions between FtsZ and both sites of MinC identified here are important for assembly of FtsZ-MinC-MinD complexes and that the conserved C-terminal end of FtsZ is not required for MinC-MinD complex formation with GTP-dependent FtsZ polymers.IMPORTANCEBacterial cell division proceeds through the coordinated assembly of the FtsZ-ring, or Z-ring, at the site of division. Assembly of the Z-ring requires polymerization of FtsZ, which is regulated by several proteins in the cell. InEscherichia coli, the Min system, which contains MinC, MinD, and MinE proteins, exhibits polar oscillation and inhibits the assembly of FtsZ at nonseptal locations. Here, we identify regions on the surface of MinC that are important for contacting FtsZ and destabilizing FtsZ polymers.

scholarly journals FtsZ from Divergent Foreign Bacteria Can Function for Cell Division in Escherichia coli

2006 ◽  
Vol 188 (20) ◽  
pp. 7132-7140 ◽  
Author(s):  
Masaki Osawa ◽  
Harold P. Erickson
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Point Mutations ◽  
Loss Of Function ◽  
Mycoplasma Pulmonis ◽  
E Coli ◽  
Z Ring ◽  
Ftsz Assembly

ABSTRACT FtsZs from Mycoplasma pulmonis (MpuFtsZ) and Bacillus subtilis (BsFtsZ) are only 46% and 53% identical in amino acid sequence to FtsZ from Escherichia coli (EcFtsZ). In the present study we show that MpuFtsZ and BsFtsZ can function for cell division in E. coli provided we make two modifications. First, we replaced their C-terminal tails with that from E. coli, giving the foreign FtsZ the binding site for E. coli FtsA and ZipA. Second, we selected for mutations in the E. coli genome that facilitated division by the foreign FtsZs. These suppressor strains arose at a relatively high frequency of 10−3 to 10−5, suggesting that they involve loss-of-function mutations in multigene pathways. These pathways may be negative regulators of FtsZ or structural pathways that facilitate division by slightly defective FtsZ. Related suppressor strains were obtained for EcFtsZ containing certain point mutations or insertions of yellow fluorescent protein. The ability of highly divergent FtsZs to function for division in E. coli is consistent with a two-part mechanism. FtsZ assembles the Z ring, and perhaps generates the constriction force, through self interactions; the downstream division proteins remodel the peptidoglycan wall by interacting with each other and the wall. The C-terminal peptide of FtsZ, which binds FtsA, provides the link between FtsZ assembly and peptidoglycan remodeling.

scholarly journals Regulation of FtsZ levels inEscherichia coliin slow growth conditions

2018 ◽  
Author(s):  
Jaana Männik ◽  
Bryant E. Walker ◽  
Jaan Männik
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Cell Division ◽  
Slow Growth ◽  
Model Organism ◽  
Growth Conditions ◽  
Rapid Degradation ◽  
E Coli ◽  
Z Ring ◽  
Cell Envelopes

AbstractA key regulator of cell division in most walled bacteria is the FtsZ protein that assembles into protofilaments attached to the membrane at midcell. These dynamic protofilament assemblies, known as the Z-ring, act as a scaffold for more than two dozen proteins involved in synthesis of septal cell envelopes. What triggers the formation of the Z-ring during the cell cycle is poorly understood. InEscherichia colimodel organism, the common view is that FtsZ concentration is constant throughout its doubling time and therefore regulation of assembly should be controlled by some yet to be identified protein-protein interactions. Here we show using quantitative analysis of newly developed fluorescent reporter that FtsZ concentration varies in a cell-cycle dependent manner in slow growth conditions and that upregulation of FtsZ synthesis correlates with the formation of the Z-ring. About 4-fold upregulation of FtsZ synthesis in the first half of the cell cycle is followed by its rapid degradation by ClpXP protease in the last 10% of the cell cycle. The initiation of rapid degradation coincides with dissociation of FtsZ from the septum. Altogether, our data indicate that the Z-ring formation in slow growth conditions inE. coliis controlled by a regulatory sequence where upregulation of an essential cell cycle factor is followed by its degradation.SignificanceFtsZ is the key regulator for bacterial cell division. It initiates division by forming a dynamic ring-like structure, the Z-ring, at the mid-cell. Here we show that, contrarily to the current paradigm, FtsZ concentration inEscherichia colimodel organism varies throughout cell cycle in slow growth conditions. Faster FtsZ synthesis in the first half of the cell cycle is followed by its rapid degradation by ClpXP protease in the end of the cell cycle. Upregulation of FtsZ synthesis correlates with the formation of the Z-ring. Our data demonstrates that in slow growthE. colicell division progresses according to paradigm where upregulation of essential cell cycle factor is followed by its degradation.

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.

Compaction of the Escherichia coli nucleoid caused by Cyt1Aa

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3553-3564 ◽  
Author(s):  
Robert Manasherob ◽  
Arieh Zaritsky ◽  
Yifah Metzler ◽  
Eitan Ben-Dov ◽  
Mark Itsko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Dna Replication ◽  
Bacillus Thuringiensis ◽  
Cell Volume ◽  
Cytoplasmic Membrane ◽  
Whole Cell ◽  
Clear Separation ◽  
Immunofluorescence Labelling

Compaction of the Escherichia coli nucleoid in the cell's centre was associated with the loss of colony-forming ability; these effects were caused by induction of Cyt1Aa, the cytotoxic 27 kDa protein from Bacillus thuringiensis subsp. israelensis. Cyt1Aa-affected compaction of the nucleoids was delayed but eventually more intense than compaction caused by chloramphenicol. The possibility that small, compact nucleoids in Cyt1Aa-expressing cells resulted in DNA replication run-out and segregation following cell division was ruled out by measuring relative nucleoid length. Treatments with membrane-perforating substances other than Cyt1Aa did not cause such compaction of the nucleoids, but rather the nucleoids overexpanded to occupy nearly all of the cell volume. These findings support the suggestion that, in addition to its perforating ability, Cyt1Aa causes specific disruption of nucleoid associations with the cytoplasmic membrane. In situ immunofluorescence labelling with Alexa did not demonstrate a great amount of Cyt1Aa associated with the membrane. Clear separation between Alexa-labelled Cyt1Aa and 4′,6-diamidino-2-phenylindole (DAPI)-stained DNA indicates that the nucleoid does not bind Cyt1Aa. Around 2 h after induction, nucleoids in Cyt1Aa-expressing cells started to decompact and expanded to fill the whole cell volume, most likely due to partial cell lysis without massive peptidoglycan destruction.

scholarly journals Differential Suppression of priA2::kan Phenotypes in Escherichia coli K-12 by Mutations in priA, lexA, and dnaC

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Steven J Sandler ◽  
Hardeep S Samra ◽  
Alvin J Clark
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Mutant Allele ◽  
Wild Type ◽  
Suppressor Mutations ◽  
Dnab Helicase ◽  
K 12 ◽  
Extragenic Suppressors ◽  
Assembly Activity

Abstract First identified as an essential component of the ϕX174 in vitro DNA replication system, PriA has ATPase, helicase, translocase, and primosome-assembly activities. priA1::kan strains of Escherichia coli are sensitive to UV irradiation, deficient in homologous recombination following transduction, and filamentous. priA2::kan strains have eightfold higher levels of uninduced SOS expression than wild type. We show that (1) priA1::kan strains have eightfold higher levels of uninduced SOS expression, (2) priA2::kan strains are UVS and Rec−, (3) lexA3 suppresses the high basal levels of SOS expression of a priA2::kan strain, and (4) plasmid-encoded priA300 (K230R), a mutant allele retaining only the primosome-assembly activity of priA+, restores both UVR and Rec+ phenotypes to a priA2::kan strain. Finally, we have isolated 17 independent UVR Rec+ revertants of priA2::kan strains that carry extragenic suppressors. All 17 map in the C-terminal half of the dnaC gene. DnaC loads the DnaB helicase onto DNA as a prelude for primosome assembly and DNA replication. We conclude that priA's primosome-assembly activity is essential for DNA repair and recombination and that the dnaC suppressor mutations allow these processes to occur in the absence of priA.

MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria
Keyword(s):  
Cell Division ◽  
Single Point ◽  
Point Mutations ◽  
Direct Interaction ◽  
Ring Formation ◽  
Z Ring ◽  
Single Point Mutations ◽  
Biochemical Analyses ◽  
Ftsz Assembly ◽  
The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

Sign in / Sign up

Export Citation Format

Share Document