Dynamic FtsZ polymerization is sensitive to the GTP to GDP ratio and can be maintained at steady state using a GTP-regeneration system

Microbiology ◽  
2003 ◽  
Vol 149 (8) ◽  
pp. 2235-2242 ◽  
Author(s):  
Elaine Small ◽  
Stephen G. Addinall
Keyword(s):  
Steady State ◽  
Cell Division ◽  
Dynamic Properties ◽  
Bacterial Cell Division ◽  
Regeneration System ◽  
Z Ring ◽  
Cell Division Protein ◽  
Hydrolysis Of

In vitro polymerization of the essential bacterial cell division protein FtsZ, in the presence of GTP, is rapid and transient due to its efficient binding and hydrolysis of GTP. In contrast, the in vivo polymeric FtsZ structure which drives cell division – the Z-ring – is present in cells for extended periods of time whilst undergoing constant turnover of FtsZ. It is demonstrated that dynamic polymerization of Escherichia coli FtsZ in vitro is sensitive to the ratio of GTP to GDP concentration. Increase of GDP concentration in the presence of a constant GTP concentration reduces both the duration of FtsZ polymerization and the initial light-scattering maximum which occurs upon addition of GTP. It is also demonstrated that by use of a GTP-regeneration system, polymers of FtsZ can be maintained in a steady state for up to 85 min, while preserving their dynamic properties. The authors therefore present the use of a GTP-regeneration system for FtsZ polymerization as an assay more representative of the in vivo situation, where FtsZ polymers are subject to a constant, relatively high GTP to GDP ratio.

scholarly journals A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Félix Ramos-León ◽  
Matthew J Bush ◽  
Joseph W Sallmen ◽  
Govind Chandra ◽  
Jake Richardson ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Mycobacterium Smegmatis ◽  
Bacterial Cell Division ◽  
Z Ring ◽  
Cell Division Protein ◽  
Ring Architecture ◽  
Contractile Structure

Bacterial cell division is driven by the polymerization of the GTPase FtsZ into a contractile structure, the so-called Z-ring. This essential process involves proteins that modulate FtsZ dynamics and hence the overall Z-ring architecture. Actinobacteria like Streptomyces and Mycobacterium lack known key FtsZ-regulators. Here we report the identification of SepH, a conserved actinobacterial protein that directly regulates FtsZ dynamics. We show that SepH is crucially involved in cell division in Streptomyces venezuelae and that it binds FtsZ via a conserved helix-turn-helix motif, stimulating the assembly of FtsZ protofilaments. Comparative in vitro studies using the SepH homolog from Mycobacterium smegmatis further reveal that SepH can also bundle FtsZ protofilaments, indicating an additional Z-ring stabilizing function in vivo. We propose that SepH plays a crucial role at the onset of cytokinesis in actinobacteria by promoting the assembly of FtsZ filaments into division-competent Z-rings that can go on to mediate septum synthesis.

scholarly journals A conserved cell division protein directly regulates FtsZ dynamics in filamentous and unicellular actinobacteria

2020 ◽  
Author(s):  
Felix Ramos-Léon ◽  
Matthew J. Bush ◽  
Joseph W. Sallmen ◽  
Govind Chandra ◽  
Jake Richardson ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Crucial Role ◽  
Bacterial Cell Division ◽  
Z Ring ◽  
Cell Division Protein ◽  
Ring Architecture ◽  
Contractile Structure

AbstractBacterial cell division is driven by the polymerization of the GTPase FtsZ into a contractile structure, the so-called Z-ring. This essential process involves proteins that modulate FtsZ dynamics and hence the overall Z-ring architecture. Actinobacteria, like Streptomyces and Mycobacterium lack known key FtsZ-regulators. Here we report the identification of SepH, a conserved actinobacterial protein that directly regulates FtsZ dynamics. We show that SepH is crucially involved in cell division in Streptomyces and that it binds FtsZ via a conserved helix-turn-helix motif, stimulating the assembly of FtsZ protofilaments. Comparative in vitro studies using the SepH homolog from Mycobacterium further reveal that SepH can also bundle FtsZ protofilaments, indicating an additional Z-ring stabilizing function in vivo. We propose that SepH plays a crucial role at the onset of cytokinesis in actinobacteria by promoting the rapid assembly of FtsZ filaments into division-competent Z-rings that can go on to mediate septum synthesis.

scholarly journals Architecture of the ring formed by the tubulin homologue FtsZ in bacterial cell division

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Piotr Szwedziak ◽  
Qing Wang ◽  
Tanmay A M Bharat ◽  
Matthew Tsim ◽  
Jan Löwe
Keyword(s):  
Cell Division ◽  
Molecular Model ◽  
Three Dimensional ◽  
Bacterial Cell Division ◽  
Electron Cryomicroscopy ◽  
E Coli ◽  
Ftsz Ring ◽  
Z Ring

Membrane constriction is a prerequisite for cell division. The most common membrane constriction system in prokaryotes is based on the tubulin homologue FtsZ, whose filaments in E. coli are anchored to the membrane by FtsA and enable the formation of the Z-ring and divisome. The precise architecture of the FtsZ ring has remained enigmatic. In this study, we report three-dimensional arrangements of FtsZ and FtsA filaments in C. crescentus and E. coli cells and inside constricting liposomes by means of electron cryomicroscopy and cryotomography. In vivo and in vitro, the Z-ring is composed of a small, single-layered band of filaments parallel to the membrane, creating a continuous ring through lateral filament contacts. Visualisation of the in vitro reconstituted constrictions as well as a complete tracing of the helical paths of the filaments with a molecular model favour a mechanism of FtsZ-based membrane constriction that is likely to be accompanied by filament sliding.

scholarly journals ZapE Is a Novel Cell Division Protein Interacting with FtsZ and Modulating the Z-Ring Dynamics

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Benoit S. Marteyn ◽  
Gouzel Karimova ◽  
Andrew K. Fenton ◽  
Anastasia D. Gazi ◽  
Nicholas West ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Dependent Manner ◽  
Bacterial Cell Division ◽  
Low Oxygen ◽  
Ftsz Ring ◽  
Division Process ◽  
Z Ring ◽  
Cell Division Protein

ABSTRACTBacterial cell division requires the formation of a mature divisome complex positioned at the midcell. The localization of the divisome complex is determined by the correct positioning, assembly, and constriction of the FtsZ ring (Z-ring). Z-ring constriction control remains poorly understood and (to some extent) controversial, probably due to the fact that this phenomenon is transient and controlled by numerous factors. Here, we characterize ZapE, a novel ATPase found in Gram-negative bacteria, which is required for growth under conditions of low oxygen, while loss ofzapEresults in temperature-dependent elongation of cell shape. We found that ZapE is recruited to the Z-ring during late stages of the cell division process and correlates with constriction of the Z-ring. Overexpression or inactivation ofzapEleads to elongation ofEscherichia coliand affects the dynamics of the Z-ring during division.In vitro, ZapE destabilizes FtsZ polymers in an ATP-dependent manner.IMPORTANCEBacterial cell division has mainly been characterizedin vitro. In this report, we could identify ZapE as a novel cell division protein which is not essentialin vitrobut is required during an infectious process. The bacterial cell division process relies on the assembly, positioning, and constriction of FtsZ ring (the so-called Z-ring). Among nonessential cell division proteins recently identified, ZapE is the first in which detection at the Z-ring correlates with its constriction. We demonstrate that ZapE abundance has to be tightly regulated to allow cell division to occur; absence or overexpression of ZapE leads to bacterial filamentation. AszapEis not essential, we speculate that additional Z-ring destabilizing proteins transiently recruited during late cell division process might be identified in the future.

scholarly journals Lateral interactions between protofilaments of the bacterial tubulin homolog FtsZ are essential for cell division

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Fenghui Guan ◽  
Jiayu Yu ◽  
Jie Yu ◽  
Yang Liu ◽  
Ying Li ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Cell ◽  
Dynamic Structure ◽  
Living Cells ◽  
Lateral Interactions ◽  
Bacterial Cell Division ◽  
Z Ring ◽  
Crystallographic Structures ◽  
Order Structures

The prokaryotic tubulin homolog FtsZ polymerizes into protofilaments, which further assemble into higher-order structures at future division sites to form the Z-ring, a dynamic structure essential for bacterial cell division. The precise nature of interactions between FtsZ protofilaments that organize the Z-ring and their physiological significance remain enigmatic. In this study, we solved two crystallographic structures of a pair of FtsZ protofilaments, and demonstrated that they assemble in an antiparallel manner through the formation of two different inter-protofilament lateral interfaces. Our in vivo photocrosslinking studies confirmed that such lateral interactions occur in living cells, and disruption of the lateral interactions rendered cells unable to divide. The inherently weak lateral interactions enable FtsZ protofilaments to self-organize into a dynamic Z-ring. These results have fundamental implications for our understanding of bacterial cell division and for developing antibiotics that target this key process.

scholarly journals Probing for Binding Regions of the FtsZ Protein Surface through Site-Directed Insertions: Discovery of Fully Functional FtsZ-Fluorescent Proteins

2016 ◽  
Vol 199 (1) ◽  
Author(s):  
Desmond A. Moore ◽  
Zakiya N. Whatley ◽  
Chandra P. Joshi ◽  
Masaki Osawa ◽  
Harold P. Erickson
Keyword(s):  
Cell Division ◽  
Fluorescent Proteins ◽  
Sole Source ◽  
Ring Structure ◽  
Content Type ◽  
Z Ring ◽  
Complete Cell ◽  
The Right

ABSTRACT FtsZ, a bacterial tubulin homologue, is a cytoskeletal protein that assembles into protofilaments that are one subunit thick. These protofilaments assemble further to form a “Z ring” at the center of prokaryotic cells. The Z ring generates a constriction force on the inner membrane and also serves as a scaffold to recruit cell wall remodeling proteins for complete cell division in vivo. One model of the Z ring proposes that protofilaments associate via lateral bonds to form ribbons; however, lateral bonds are still only hypothetical. To explore potential lateral bonding sites, we probed the surface of Escherichia coli FtsZ by inserting either small peptides or whole fluorescent proteins (FPs). Among the four lateral surfaces on FtsZ protofilaments, we obtained inserts on the front and back surfaces that were functional for cell division. We concluded that these faces are not sites of essential interactions. Inserts at two sites, G124 and R174, located on the left and right surfaces, completely blocked function, and these sites were identified as possible sites for essential lateral interactions. However, the insert at R174 did not interfere with association of protofilaments into sheets and bundles in vitro. Another goal was to find a location within FtsZ that supported insertion of FP reporter proteins while allowing the FtsZ-FPs to function as the sole source of FtsZ. We discovered one internal site, G55-Q56, where several different FPs could be inserted without impairing function. These FtsZ-FPs may provide advances for imaging Z-ring structure by superresolution techniques. IMPORTANCE One model for the Z-ring structure proposes that protofilaments are assembled into ribbons by lateral bonds between FtsZ subunits. Our study excluded the involvement of the front and back faces of the protofilament in essential interactions in vivo but pointed to two potential lateral bond sites, on the right and left sides. We also identified an FtsZ loop where various fluorescent proteins could be inserted without blocking function; these FtsZ-FPs functioned as the sole source of FtsZ. This advance provides improved tools for all fluorescence imaging of the Z ring and may be especially important for superresolution imaging.

scholarly journals ZapA tetramerization is required for midcell localization and ZapB interaction in Escherichia coli

2019 ◽  
Author(s):  
Nils Y. Meiresonne ◽  
Tanneke den Blaauwen
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Bacterial Cell Division ◽  
Cellular Processes ◽  
Interaction Partners ◽  
Associated Proteins

AbstractBacterial cell division is guided by FtsZ treadmilling precisely at midcell. FtsZ itself is regulated by FtsZ associated proteins (Zaps) that couple it to different cellular processes. ZapA is known to enhance FtsZ bundling but also forms the synchronizing link with chromosome segregation through ZapB and matS bound MatP. ZapA exists as dimers and tetramers in the cell. Using the ZapAI83E mutant that only forms dimers, this paper investigates the effects of ZapA multimerization state on its interaction partners and cell division. By employing (fluorescence) microscopy and Förster Resonance Energy Transfer in vivo it is shown that; dimeric ZapA is unable to complement a zapA deletion strain and localizes diffusely through the cell but still interacts with FtsZ that is not part of the cell division machinery. Dimeric ZapA is unable to recruit ZapB, which localizes in its presence unipolarly in the cell. Interestingly, the localization profiles of the chromosome and unipolar ZapB anticorrelate. The work presented here confirms previously reported in vitro effects of ZapA multimerization in vivo and further places it in a broader context by revealing the strong implications for ZapB localization and ter linkage.

scholarly journals LocZ Is a New Cell Division Protein Involved in Proper Septum Placement in Streptococcus pneumoniae

mBio ◽  
2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Nela Holečková ◽  
Linda Doubravová ◽  
Orietta Massidda ◽  
Virginie Molle ◽  
Karolína Buriánková ◽  
...  
Keyword(s):  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Protein Kinase ◽  
Bacterial Cell Division ◽  
Content Type ◽  
Daughter Cells ◽  
Division Site ◽  
Z Ring ◽  
Specific Shape ◽  
Cell Division Protein

ABSTRACTHow bacteria control proper septum placement at midcell, to guarantee the generation of identical daughter cells, is still largely unknown. Although different systems involved in the selection of the division site have been described in selected species, these do not appear to be widely conserved. Here, we report that LocZ (Spr0334), a newly identified cell division protein, is involved in proper septum placement inStreptococcus pneumoniae. We show thatlocZis not essential but that its deletion results in cell division defects and shape deformation, causing cells to divide asymmetrically and generate unequally sized, occasionally anucleated, daughter cells. LocZ has a unique localization profile. It arrives early at midcell, before FtsZ and FtsA, and leaves the septum early, apparently moving along with the equatorial rings that mark the future division sites. Consistently, cells lacking LocZ also show misplacement of the Z-ring, suggesting that it could act as a positive regulator to determine septum placement. LocZ was identified as a substrate of the Ser/Thr protein kinase StkP, which regulates cell division in S. pneumoniae. Interestingly, homologues of LocZ are found only in streptococci, lactococci, and enterococci, indicating that this close phylogenetically related group of bacteria evolved a specific solution to spatially regulate cell division.IMPORTANCEBacterial cell division is a highly ordered process regulated in time and space. Recently, we reported that the Ser/Thr protein kinase StkP regulates cell division in Streptococcus pneumoniae, through phosphorylation of several key proteins. Here, we characterized one of the StkP substrates, Spr0334, which we named LocZ. We show that LocZ is a new cell division protein important for proper septum placement and likely functions as a marker of the cell division site. Consistently, LocZ supports proper Z-ring positioning at midcell. LocZ is conserved only among streptococci, lactococci, and enterococci, which lack homologues of the Min and nucleoid occlusion effectors, indicating that these bacteria adapted a unique mechanism to find their middle, reflecting their specific shape and symmetry.

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