scholarly journals MapZ forms a stable ring structure that acts as a nano-track for FtsZ treadmilling inStreptococcus mutans

2017 ◽  
Author(s):  
Yongliang Li ◽  
Shipeng Shao ◽  
Xiao Xu ◽  
Xiaodong Su ◽  
Yujie Sun ◽  
...  
Keyword(s):  
Single Molecule ◽  
Super Resolution ◽  
Ring Structure ◽  
Antibacterial Drug ◽  
Ftsz Ring ◽  
Division Site ◽  
Binary Division ◽  
Z Ring ◽  
Vital Component ◽  
Stable Ring

AbstractBacterial binary division requires the accurate placement of the division machinery. FtsZ, the vital component of the division machinery, can assemble into filaments and self-organize into a ring structure (Z-ring) at the proper site for cell division. Thus, understanding how bacteria control the spatiotemporal formation of the FtsZ ring is crucial for small molecule and nanoparticle antibacterial drug discovery. MapZ, a recently identified FtsZ regulator inStreptococcaceae,has been found to localize at the mid-cell and position the FtsZ ring. However, the mechanism is still unclear. Here, by using total internal reflection fluorescence microscopy, super-resolution imaging, and single molecule tracking, we investigated the mechanism by which MapZ regulates the FtsZ ring position. The results show that FtsZ exhibites dynamic treadmilling motion in S.mutans.Importantly, depletion of MapZ leads to an unconstrained movement of treadmilling FtsZ filaments and a shorter lifetime of the constricting FtsZ ring. Furthermore, by revealing that MapZ forms an immobile ring-like nanostructure at the division site, our study suggests that MapZ forms a stable ring that acts as a nanotrack to guide and restrict treadmilling FtsZ filaments in S.mutans, representing a novel way in which bacteria control the division.

scholarly journals Effects of Perturbing Nucleoid Structure on Nucleoid Occlusion-Mediated Toporegulation of FtsZ Ring Assembly

2004 ◽  
Vol 186 (12) ◽  
pp. 3951-3959 ◽  
Author(s):  
Qin Sun ◽  
William Margolin
Keyword(s):  
Chromosome Segregation ◽  
Potential Role ◽  
Membrane Insertion ◽  
Translation Inhibition ◽  
Ftsz Ring ◽  
Division Site ◽  
Ring Assembly ◽  
Z Ring ◽  
Nucleoid Structure

ABSTRACT In Escherichia coli, assembly of the FtsZ ring (Z ring) at the cell division site is negatively regulated by the nucleoid in a phenomenon called nucleoid occlusion (NO). Previous studies have indicated that chromosome packing plays a role in NO, as mukB mutants grown in rich medium often exhibit FtsZ rings on top of diffuse, unsegregated nucleoids. To address the potential role of overall nucleoid structure on NO, we investigated the effects of disrupting chromosome structure on Z-ring positioning. We found that NO was mostly normal in cells with inactivated DNA gyrase or in mukB-null mutants lacking topA, although some suppression of NO was evident in the latter case. Previous reports suggesting that transcription, translation, and membrane insertion of proteins (“transertion”) influence nucleoid structure prompted us to investigate whether disruption of these activities had effects on NO. Blocking transcription caused nucleoids to become diffuse, and FtsZ relocalized to multiple bands on top of these nucleoids, biased towards midcell. This suggested that these diffuse nucleoids were defective in NO. Blocking translation with chloramphenicol caused characteristic nucleoid compaction, but FtsZ rarely assembled on top of these centrally positioned nucleoids. This suggested that NO remained active upon translation inhibition. Blocking protein secretion by thermoinduction of a secA(Ts) strain caused a chromosome segregation defect similar to that in parC mutants, and NO was active. Although indirect effects are certainly possible with these experiments, the above data suggest that optimum NO activity may require specific organization and structure of the nucleoid.

scholarly journals Insights into the Structure, Function, and Dynamics of the Bacterial Cytokinetic FtsZ-Ring

2020 ◽  
Vol 49 (1) ◽  
pp. 309-341 ◽  
Author(s):  
Ryan McQuillen ◽  
Jie Xiao
Keyword(s):  
Cell Division ◽  
Structure Function ◽  
Single Molecule ◽  
Gtp Hydrolysis ◽  
Major Function ◽  
The Past ◽  
Division Site ◽  
Z Ring ◽  
Resolution Imaging

The FtsZ protein is a highly conserved bacterial tubulin homolog. In vivo, the functional form of FtsZ is the polymeric, ring-like structure (Z-ring) assembled at the future division site during cell division. While it is clear that the Z-ring plays an essential role in orchestrating cytokinesis, precisely what its functions are and how these functions are achieved remain elusive. In this article, we review what we have learned during the past decade about the Z-ring's structure, function, and dynamics, with a particular focus on insights generated by recent high-resolution imaging and single-molecule analyses. We suggest that the major function of the Z-ring is to govern nascent cell pole morphogenesis by directing the spatiotemporal distribution of septal cell wall remodeling enzymes through the Z-ring's GTP hydrolysis–dependent treadmilling dynamics. In this role, FtsZ functions in cell division as the counterpart of the cell shape–determining actin homolog MreB in cell elongation.

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 Simultaneous spatiotemporal super-resolution and multi-parametric fluorescence microscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jagadish Sankaran ◽  
Harikrushnan Balasubramanian ◽  
Wai Hoh Tang ◽  
Xue Wen Ng ◽  
Adrian Röllin ◽  
...  
Keyword(s):  
Single Molecule ◽  
Temporal Dynamics ◽  
Growth Factor Receptor ◽  
Super Resolution ◽  
Actin Binding ◽  
Biological Knowledge ◽  
Data Set ◽  
Epidermal Growth ◽  
Molecular Brightness ◽  
Super Resolution Microscopy

AbstractSuper-resolution microscopy and single molecule fluorescence spectroscopy require mutually exclusive experimental strategies optimizing either temporal or spatial resolution. To achieve both, we implement a GPU-supported, camera-based measurement strategy that highly resolves spatial structures (~100 nm), temporal dynamics (~2 ms), and molecular brightness from the exact same data set. Simultaneous super-resolution of spatial and temporal details leads to an improved precision in estimating the diffusion coefficient of the actin binding polypeptide Lifeact and corrects structural artefacts. Multi-parametric analysis of epidermal growth factor receptor (EGFR) and Lifeact suggests that the domain partitioning of EGFR is primarily determined by EGFR-membrane interactions, possibly sub-resolution clustering and inter-EGFR interactions but is largely independent of EGFR-actin interactions. These results demonstrate that pixel-wise cross-correlation of parameters obtained from different techniques on the same data set enables robust physicochemical parameter estimation and provides biological knowledge that cannot be obtained from sequential measurements.

scholarly journals Comparing Super-Resolution Microscopy Techniques to Analyze Chromosomes

2021 ◽  
Vol 22 (4) ◽  
pp. 1903
Author(s):  
Ivona Kubalová ◽  
Alžběta Němečková ◽  
Klaus Weisshart ◽  
Eva Hřibová ◽  
Veit Schubert
Keyword(s):  
Single Molecule ◽  
Imaging Techniques ◽  
Chromatin Condensation ◽  
Super Resolution ◽  
Stimulated Emission ◽  
Wide Field ◽  
Structured Illumination Microscopy ◽  
Metaphase Chromosomes ◽  
Localization Microscopy ◽  
Super Resolution Microscopy

The importance of fluorescence light microscopy for understanding cellular and sub-cellular structures and functions is undeniable. However, the resolution is limited by light diffraction (~200–250 nm laterally, ~500–700 nm axially). Meanwhile, super-resolution microscopy, such as structured illumination microscopy (SIM), is being applied more and more to overcome this restriction. Instead, super-resolution by stimulated emission depletion (STED) microscopy achieving a resolution of ~50 nm laterally and ~130 nm axially has not yet frequently been applied in plant cell research due to the required specific sample preparation and stable dye staining. Single-molecule localization microscopy (SMLM) including photoactivated localization microscopy (PALM) has not yet been widely used, although this nanoscopic technique allows even the detection of single molecules. In this study, we compared protein imaging within metaphase chromosomes of barley via conventional wide-field and confocal microscopy, and the sub-diffraction methods SIM, STED, and SMLM. The chromosomes were labeled by DAPI (4′,6-diamidino-2-phenylindol), a DNA-specific dye, and with antibodies against topoisomerase IIα (Topo II), a protein important for correct chromatin condensation. Compared to the diffraction-limited methods, the combination of the three different super-resolution imaging techniques delivered tremendous additional insights into the plant chromosome architecture through the achieved increased resolution.

scholarly journals Graphene Energy Transfer for Single‐Molecule Biophysics, Biosensing, and Super‐Resolution Microscopy

2021 ◽  
pp. 2101099
Author(s):  
Izabela Kamińska ◽  
Johann Bohlen ◽  
Renukka Yaadav ◽  
Patrick Schüler ◽  
Mario Raab ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Single Molecule ◽  
Super Resolution ◽  
Single Molecule Biophysics ◽  
Super Resolution Microscopy

scholarly journals A simple and versatile design concept for fluorophore derivatives with intramolecular photostabilization

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Jasper H. M. van der Velde ◽  
Jens Oelerich ◽  
Jingyi Huang ◽  
Jochem H. Smit ◽  
Atieh Aminian Jazi ◽  
...  
Keyword(s):  
Single Molecule ◽  
Unnatural Amino Acids ◽  
Photophysical Properties ◽  
Super Resolution ◽  
Single Step ◽  
General Strategy ◽  
Self Healing ◽  
Chemical Transformations ◽  
Scaffolding Strategy ◽  
Organic Fluorophore

Abstract Intramolecular photostabilization via triple-state quenching was recently revived as a tool to impart synthetic organic fluorophores with ‘self-healing’ properties. To date, utilization of such fluorophore derivatives is rare due to their elaborate multi-step synthesis. Here we present a general strategy to covalently link a synthetic organic fluorophore simultaneously to a photostabilizer and biomolecular target via unnatural amino acids. The modular approach uses commercially available starting materials and simple chemical transformations. The resulting photostabilizer–dye conjugates are based on rhodamines, carbopyronines and cyanines with excellent photophysical properties, that is, high photostability and minimal signal fluctuations. Their versatile use is demonstrated by single-step labelling of DNA, antibodies and proteins, as well as applications in single-molecule and super-resolution fluorescence microscopy. We are convinced that the presented scaffolding strategy and the improved characteristics of the conjugates in applications will trigger the broader use of intramolecular photostabilization and help to emerge this approach as a new gold standard.

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