scholarly journals Bacterial Cell Wall Synthesis: New Insights from Localization Studies

2005 ◽  
Vol 69 (4) ◽  
pp. 585-607 ◽  
Author(s):  
Dirk-Jan Scheffers ◽  
Mariana G. Pinho
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cell Shape ◽  
Fluorescent Protein ◽  
Model Organisms ◽  
Live Cells ◽  
Cell Wall Synthesis ◽  
A Cell ◽  
Green Fluorescent ◽  
Bacterial Cell Shape

SUMMARY In order to maintain shape and withstand intracellular pressure, most bacteria are surrounded by a cell wall that consists mainly of the cross-linked polymer peptidoglycan (PG). The importance of PG for the maintenance of bacterial cell shape is underscored by the fact that, for various bacteria, several mutations affecting PG synthesis are associated with cell shape defects. In recent years, the application of fluorescence microscopy to the field of PG synthesis has led to an enormous increase in data on the relationship between cell wall synthesis and bacterial cell shape. First, a novel staining method enabled the visualization of PG precursor incorporation in live cells. Second, penicillin-binding proteins (PBPs), which mediate the final stages of PG synthesis, have been localized in various model organisms by means of immunofluorescence microscopy or green fluorescent protein fusions. In this review, we integrate the knowledge on the last stages of PG synthesis obtained in previous studies with the new data available on localization of PG synthesis and PBPs, in both rod-shaped and coccoid cells. We discuss a model in which, at least for a subset of PBPs, the presence of substrate is a major factor in determining PBP localization.

scholarly journals Bacteriophage SP01 Gene Product 56 Inhibits Bacillus subtilis Cell Division by Interacting with FtsL and Disrupting Pbp2B and FtsW Recruitment

2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Gene Product ◽  
Fluorescent Protein ◽  
Lytic Bacteriophage ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Ftsz Ring ◽  
Green Fluorescent

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.

scholarly journals Barriers to Diffusion in Cells: Visualization of Membraneless Particles in the Nucleus

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Leonel Malacrida ◽  
Per Niklas Hedde ◽  
Belen Torrado ◽  
Enrico Gratton
Keyword(s):  
Correlation Function ◽  
Phase Separation ◽  
Pair Correlation Function ◽  
Fluorescent Protein ◽  
Pair Correlation ◽  
Live Cells ◽  
Supramolecular Organization ◽  
Transient Nature ◽  
A Cell ◽  
Green Fluorescent

ABSTRACT Transient barriers are fundamental to cell supramolecular organization and assembly. Discontinuities between spaces can be generated by a physical barrier but also by thermodynamic barriers achieved by phase separation of molecules. However, because of the transient nature and the lack of a visible barrier, the existence of phase separation is difficult to demonstrate experimentally. We describe an approach based on the 2-dimensional pair correlation function (2D-pCF) analysis of the spatial connectivity in a cell. The educational aim of the article is to present both a model suitable for explaining diffusion barrier measurements to a broad range of courses and examples of biological situations. If there are no barriers to diffusion, particles could diffuse equally in all directions. In this situation the pair correlation function introduced in this article is independent of the direction and is uniform in all directions. However, in the presence of obstacles, the shape of the 2D-pCF is distorted to reflect how the obstacle position and orientation change the flow of molecules. In the example shown in this article, measurements of diffusion of enhanced green fluorescent protein moving in live cells show the lack of connectivity at the nucleolus surface for shorter distances. We also observe a gradual increase in the connectivity for longer distances or times, presumably because of molecular trajectories around the nucleolus.

scholarly journals FtsEX-mediated regulation of inner membrane fusion and cell separation reveals morphogenetic plasticity inCaulobacter crescentus

2017 ◽  
Author(s):  
Elizabeth L. Meier ◽  
Qing Yao ◽  
Allison K. Daitch ◽  
Grant J. Jensen ◽  
Erin D. Goley
Keyword(s):  
Cell Wall ◽  
Membrane Fusion ◽  
Bacterial Cell ◽  
Cell Separation ◽  
Cell Shape ◽  
Caulobacter Crescentus ◽  
Inner Membrane ◽  
Bacterial Cell Shape ◽  
Late Stages ◽  
Shape Changes

AbstractDuring its life cycle,Caulobacter crescentusundergoes a series of coordinated shape changes, including generation of a polar stalk and reshaping of the cell envelope to produce new daughter cells through the process of cytokinesis. The mechanisms by which these morphogenetic processes are coordinated in time and space remain largely unknown. Here we demonstrate that the conserved division complex FtsEX controls both the early and late stages of cytokinesis inC. crescentus, namely initiation of constriction and final cell separation. ΔftsEcells display a striking phenotype: cells are chained, with skinny connections between cell bodies resulting from defects in inner membrane fusion and cell separation. Surprisingly, the thin connections in ΔftsEcells share morphological and molecular features withC. crescentusstalks. Our data uncover unanticipated morphogenetic plasticity inC. crescentus, with loss of FtsE causing a stalk-like program to take over at failed division sites and yield novel cell morphology.Author SummaryBacterial cell shape is genetically hardwired and is critical for fitness and, in certain cases, pathogenesis. In most bacteria, a semi-rigid structure called the cell wall surrounds the inner membrane, offering protection against cell lysis while simultaneously maintaining cell shape. A highly dynamic macromolecular structure, the cell wall undergoes extensive remodeling as bacterial cells grow and divide. We demonstrate that a broadly conserved cell division complex, FtsEX, relays signals from the cytoplasm to the cell wall to regulate key developmental shape changes in the α-proteobacteriumCaulobacter crescentus. Consistent with studies in diverse bacteria, we observe strong synthetic interactions betweenftsEand cell wall hydrolytic factors, suggesting that regulation of cell wall remodeling is a conserved function of FtsEX. Loss of FtsE causes morphological defects associated with both the early and late stages of division. Intriguingly, without FtsE, cells frequently fail to separate and instead elaborate a thin, tubular structure between cell bodies, a growth mode observed in other α-proteobacteria. Overall, our results highlight the plasticity of bacterial cell shape and demonstrate how altering the activity of one morphogenetic program can produce diverse morphologies resembling those of other bacteria in nature.

scholarly journals Motile Properties of Vimentin Intermediate Filament Networks in Living Cells

1998 ◽  
Vol 143 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Miri Yoon ◽  
Robert D. Moir ◽  
Veena Prahlad ◽  
Robert D. Goldman
Keyword(s):  
Intermediate Filament ◽  
Cell Shape ◽  
Fluorescence Recovery After Photobleaching ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
Living Cells ◽  
A Cell ◽  
Filament Networks ◽  
Green Fluorescent ◽  
Vimentin Intermediate Filament

The motile properties of intermediate filament (IF) networks have been studied in living cells expressing vimentin tagged with green fluorescent protein (GFP-vimentin). In interphase and mitotic cells, GFP-vimentin is incorporated into the endogenous IF network, and accurately reports the behavior of IF. Time-lapse observations of interphase arrays of vimentin fibrils demonstrate that they are constantly changing their configurations in the absence of alterations in cell shape. Intersecting points of vimentin fibrils, or foci, frequently move towards or away from each other, indicating that the fibrils can lengthen or shorten. Fluorescence recovery after photobleaching shows that bleach zones across fibrils rapidly recover their fluorescence. During this recovery, bleached zones frequently move, indicating translocation of fibrils. Intriguingly, neighboring fibrils within a cell can exhibit different rates and directions of movement, and they often appear to extend or elongate into the peripheral regions of the cytoplasm. In these same regions, short filamentous structures are also seen actively translocating. All of these motile properties require energy, and the majority appear to be mediated by interactions of IF with microtubules and microfilaments.

scholarly journals The evolution of spherical cell shape; progress and perspective

2019 ◽  
Vol 47 (6) ◽  
pp. 1621-1634 ◽  
Author(s):  
Paul Richard Jesena Yulo ◽  
Heather Lyn Hendrickson
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cell Shape ◽  
Shape Change ◽  
Spherical Cell ◽  
Shape Evolution ◽  
Penicillin Binding Proteins ◽  
Cell Shape Change ◽  
Peptidoglycan Cell Wall ◽  
Bacterial Cell Shape

Bacterial cell shape is a key trait governing the extracellular and intracellular factors of bacterial life. Rod-like cell shape appears to be original which implies that the cell wall, division, and rod-like shape came together in ancient bacteria and that the myriad of shapes observed in extant bacteria have evolved from this ancestral shape. In order to understand its evolution, we must first understand how this trait is actively maintained through the construction and maintenance of the peptidoglycan cell wall. The proteins that are primarily responsible for cell shape are therefore the elements of the bacterial cytoskeleton, principally FtsZ, MreB, and the penicillin-binding proteins. MreB is particularly relevant in the transition between rod-like and spherical cell shape as it is often (but not always) lost early in the process. Here we will highlight what is known of this particular transition in cell shape and how it affects fitness before giving a brief perspective on what will be required in order to progress the field of cell shape evolution from a purely mechanistic discipline to one that has the perspective to both propose and to test reasonable hypotheses regarding the ecological drivers of cell shape change.

scholarly journals Insight into the Antiadhesive Effect of Yeast Wall Protein 1 of Candida albicans

2012 ◽  
Vol 11 (6) ◽  
pp. 795-805 ◽  
Author(s):  
Bruce L. Granger
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Fluorescent Protein ◽  
Surrounding Medium ◽  
Yeast Cells ◽  
Content Type ◽  
A Cell ◽  
Opportunistic Fungal Pathogen ◽  
Green Fluorescent

ABSTRACTYwp1 is a prominent glycosylphosphatidylinositol (GPI)-anchored glycoprotein of the cell wall ofCandida albicans; it is present in the yeast form of this opportunistic fungal pathogen but absent from filamentous forms and chlamydospores. Yeast cells that lack Ywp1 are more adhesive and form thicker biofilms, implying an antiadhesive activity for Ywp1, with a possible role in yeast dispersal. The antiadhesive effect of Ywp1 is transplantable from yeast to hyphae, as hyphae that are forced to expressYWP1lose adhesion in anin vitroassay. Deletion of the GPI anchor results in loss of Ywp1 to the surrounding medium and reduction of the antiadhesive effect, implying an importance of time-dependent residency in the cell wall. Anchor-negative versions of Ywp1 possessing or lacking a C-terminal green fluorescent protein (GFP) tag were created inC. albicansand harvested from culture supernatants; in addition to serving as quantifiable markers for Ywp1 secretion, they revealed that the cleaved 11-kDa propeptide of Ywp1 remains strongly but noncovalently associated with the Ywp1 core. This association is resistant to highly acidic and basic solutions, 8 M urea, and 1% SDS (below 45°C). Above 50°C, SDS dissociates the isolated complex, but even higher temperatures are required to dissociate the propeptide from native Ywp1 that is anchored in a cell wall. This property has permitted detection, for the first time, of orthologs of Ywp1 in other members of theCandidaclade. The cleaved propeptide, which carries the sole N-glycan of Ywp1, must participate in the antiadhesive effect of Ywp1.

scholarly journals One Repeat of the Cell Wall Binding Domain Is Sufficient for Anchoring the Lactobacillus acidophilus Surface Layer Protein

2002 ◽  
Vol 184 (16) ◽  
pp. 4617-4619 ◽  
Author(s):  
Egbert Smit ◽  
Peter H. Pouwels
Keyword(s):  
Cell Wall ◽  
Lactobacillus Acidophilus ◽  
Fluorescent Protein ◽  
Teichoic Acid ◽  
Terminal Repeat ◽  
Wall Teichoic Acid ◽  
S Protein ◽  
Cell Wall Binding ◽  
A Cell ◽  
Green Fluorescent

ABSTRACT The N-terminal repeat (SAC1) of the S-protein of Lactobacillus acidophilus bound efficiently and specifically to cell wall fragments (CWFs) when fused to green fluorescent protein, whereas the C-terminal repeat (SAC2) did not. Treatment of CWFs with hydrofluoric acid, but not phenol, prevented binding. Apparently, SAC1 is necessary and sufficient for cell wall binding. Our data suggest that SAC anchors the S-protein to a cell wall teichoic acid.

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