scholarly journals Structural basis of denuded glycan recognition by SPOR domains in bacterial cell division

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Martín Alcorlo ◽  
David A. Dik ◽  
Stefania De Benedetti ◽  
Kiran V. Mahasenan ◽  
Mijoon Lee ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cell Wall ◽  
Cell Division ◽  
Molecular Basis ◽  
Structural Basis ◽  
Bacterial Cell Division ◽  
Bacterial Proteins ◽  
Daughter Cells ◽  
Lytic Transglycosylase ◽  
Dynamics Simulations

AbstractSPOR domains are widely present in bacterial proteins that recognize cell-wall peptidoglycan strands stripped of the peptide stems. This type of peptidoglycan is enriched in the septal ring as a product of catalysis by cell-wall amidases that participate in the separation of daughter cells during cell division. Here, we document binding of synthetic denuded glycan ligands to the SPOR domain of the lytic transglycosylase RlpA from Pseudomonas aeruginosa (SPOR-RlpA) by mass spectrometry and structural analyses, and demonstrate that indeed the presence of peptide stems in the peptidoglycan abrogates binding. The crystal structures of the SPOR domain, in the apo state and in complex with different synthetic glycan ligands, provide insights into the molecular basis for recognition and delineate a conserved pattern in other SPOR domains. The biological and structural observations presented here are followed up by molecular-dynamics simulations and by exploration of the effect on binding of distinct peptidoglycan modifications.

scholarly journals The SPOR Domain, a Widely Conserved Peptidoglycan Binding Domain That Targets Proteins to the Site of Cell Division

2017 ◽  
Vol 199 (14) ◽  
Author(s):  
Atsushi Yahashiri ◽  
Matthew A. Jorgenson ◽  
David S. Weiss
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Protein Interactions ◽  
Cell Separation ◽  
Protein Protein Interactions ◽  
Target Proteins ◽  
Bacterial Proteins ◽  
Binding Domains ◽  
Division Site ◽  
Daughter Cell Separation

ABSTRACT Sporulation-related repeat (SPOR) domains are small peptidoglycan (PG) binding domains found in thousands of bacterial proteins. The name “SPOR domain” stems from the fact that several early examples came from proteins involved in sporulation, but SPOR domain proteins are quite diverse and contribute to a variety of processes that involve remodeling of the PG sacculus, especially with respect to cell division. SPOR domains target proteins to the division site by binding to regions of PG devoid of stem peptides (“denuded” glycans), which in turn are enriched in septal PG by the intense, localized activity of cell wall amidases involved in daughter cell separation. This targeting mechanism sets SPOR domain proteins apart from most other septal ring proteins, which localize via protein-protein interactions. In addition to SPOR domains, bacteria contain several other PG-binding domains that can exploit features of the cell wall to target proteins to specific subcellular sites.

scholarly journals Modification of cell wall polysaccharide spatially controls cell division in Streptococcus mutans

2020 ◽  
Author(s):  
Svetlana Zamakhaeva ◽  
Catherine T. Chaton ◽  
Jeffrey S. Rush ◽  
Sowmya Ajay Castro ◽  
Alexander E. Yarawsky ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Streptococcus Mutans ◽  
Cell Separation ◽  
Ring Structure ◽  
Cell Wall Polysaccharide ◽  
Bacterial Cell Division ◽  
Glycerol Phosphate ◽  
Immature Form ◽  
Z Ring

AbstractBacterial cell division is driven by a tubulin homolog FtsZ, which assembles into the Z-ring structure leading to the recruitment of the cell division machinery. In ovoid-shaped Gram-positive bacteria, such as streptococci, MapZ guides Z-ring positioning at cell equators through an, as yet, unknown mechanism. The cell wall of the important dental pathogen Streptococcus mutans is composed of peptidoglycan decorated with Serotype c Carbohydrates (SCCs). Here, we show that an immature form of SCC, lacking the recently identified glycerol phosphate (GroP) modification, coordinates Z-ring positioning. Pulldown assays using S. mutans cell wall combined with binding affinity analysis identified the major cell separation autolysin, AtlA, as an SCC binding protein. Importantly, AtlA binding to mature SCC is attenuated due to GroP modification. Using fluorescently-labeled AtlA, we mapped SCC distribution on the streptococcal surface to reveal that GroP-deficient immature SCCs are exclusively present at the cell poles and equators. Moreover, the equatorial GroP-deficient SCCs co-localize with MapZ throughout the S. mutans cell cycle. Consequently, in GroP-deficient mutant bacteria, proper AtlA localization is abrogated resulting in dysregulated cellular autolysis. In addition, these mutants display morphological abnormalities associated with MapZ mislocalization leading to Z-ring misplacement. Altogether, our data support a model in which GroP-deficient immature SCCs spatially coordinate the localization of AtlA and MapZ. This mechanism ensures cell separation by AtlA at poles and Z-ring alignment with the cell equator.Graphical abstract

scholarly journals Structural basis of Plasmodium vivax inhibition by antibodies binding to the circumsporozoite protein repeats

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Iga Kucharska ◽  
Lamia Hossain ◽  
Danton Ivanochko ◽  
Qiren Yang ◽  
John L Rubinstein ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Molecular Basis ◽  
Parasite Infection ◽  
Circumsporozoite Protein ◽  
Structural Basis ◽  
Structural Studies ◽  
Repeat Region ◽  
Antibody Recognition ◽  
Peptide Conformations ◽  
Dynamics Simulations

Malaria is a global health burden, with Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) responsible for the majority of infections worldwide. Circumsporozoite protein (CSP) is the most abundant protein on the surface of Plasmodium sporozoites, and antibodies targeting the central repeat region of CSP can prevent parasite infection. Although much has been uncovered about the molecular basis of antibody recognition of the PfCSP repeats, data remains scarce for PvCSP. Here, we performed molecular dynamics simulations for peptides comprising the PvCSP repeats from strains VK210 and VK247 to reveal how the PvCSP central repeats are highly disordered, with minor propensities to adopt turn conformations. Next, we solved eight crystal structures to unveil the interactions of two inhibitory monoclonal antibodies (mAbs), 2F2 and 2E10.E9, with PvCSP repeats. Both antibodies can accommodate subtle sequence variances in the repeat motifs and recognize largely coiled peptide conformations that also contain isolated turns. Our structural studies uncover various degrees of Fab-Fab homotypic interactions upon recognition of the PvCSP central repeats by these two inhibitory mAbs, similar to potent mAbs against PfCSP. These findings augment our understanding of host-Plasmodium interactions, and contribute molecular details of Pv inhibition by mAbs to unlock structure-based engineering of PvCSP-based vaccines.

Cell Volume and the Control of the Chlamydomonas Cell Cycle

1982 ◽  
Vol 54 (1) ◽  
pp. 173-191 ◽  
Author(s):  
R. A. CRAIGIE ◽  
T. CAVALIER-SMITH
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Division ◽  
Simple Model ◽  
Cell Volume ◽  
Mother Cell ◽  
Dark Period ◽  
Size Fractions ◽  
Daughter Cells ◽  
Mother Cell Wall

Chlamydomonas reinhardii divides by multiple fission to produce 2n daughter cells per division burst, where n is an integer. By separating predivision cells from synchronous cultures into fractions of differing mean cell volumes, and electronically measuring the numbers and volume distributions of the daughter cells produced by the subsequent division burst, we have shown that n is determined by the volume of the parent cell. Control of n can occur simply, if after every cell division the daughter cells monitor their volume and divide again if, and only if, their volume is greater than a fixed minimum value. In cultures synchronized by 12-h light/12-h dark cycles, the larger parent cells divide earlier in the dark period than do smaller cells. This has been shown by two independent methods: (1) by separating cells into different size fractions by Percoll density-gradient centrifugation and using the light microscope to see when they divide; and (2) by studying changes in the cell volume distribution of unfractioned cultures. Since daughter cells remain within the mother-cell wall for some hours after cell division, and cell division causes an overall swelling of the mother-cell wall, the timing of division can be determined electronically by measuring this increase in cell volume that occurs in the dark period in the absence of growth; we find that cells at the large end of the size distribution range undergo this swelling first, and are then followed by successively smaller size fractions. A simple model embodying a sizer followed by a timer gives a good quantitative fit to these data for 12-h light/12-h dark cycles if cell division occurs 12-h after attaining a critical volume of approximately 140 μm3. However, this simple model is called into question by our finding that alterations in the length of the light period alter the rate of progress towards division even of cells that have attained their critical volume. We discuss the relative roles of light and cell volume in the control of division timing in the Chlamydomonas cell cycle.

AUTORADIOGRAPHIC STUDIES OF BACTERIAL CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS IN THE PRESENCE OF CHLORAMPHENICOL

1967 ◽  
Vol 13 (4) ◽  
pp. 341-350 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Bacillus Cereus ◽  
First Generation ◽  
Third Generation ◽  
Cell Wall Synthesis ◽  
Daughter Cells ◽  
Entire Cell ◽  
Wall Growth ◽  
The Difference

The pattern of cell wall synthesis as measured by the incorporation of tritiated alanine into the cell wall of Bacillus cereus, and the number of synthesizing sites in the cell wall were studied by the direct and the reverse autoradiographic labelling methods.In the absence of chloramphenicol, the new cell wall was initiated at two or three segments, and later increased to four or five segments which continued to elongate but not to increase in number until the bacilli had made preparation for cell division. Shortly before the centripetal growth of the cell wall and constriction to separate daughter cells, two to three more new wall-segments were added to those already present. The second and third generation cells retained some old wall-segments from the first-generation mother, which remained as discrete clusters of grains, and could easily be distinguished from the new segments.In the presence of chloramphenicol, the new wall was initiated at 8 to 10 sites. Further incubation resulted in the uniform incorporation of labels at multiple sites along the entire cell length.The patterns of new wall replication as studied by the two methods were compared. To account for the difference in synthesizing sites when chloramphenicol is present, it is suggested that the cells have either used the maximum number of sites or have completely bypassed all the sites and allowed the tritiated alanine to diffuse into the wall to become incorporated.

scholarly journals The chromosomal passenger complex controls the function of endosomal sorting complex required for transport-III Snf7 proteins during cytokinesis

Open Biology ◽  
2012 ◽  
Vol 2 (5) ◽  
pp. 120070 ◽  
Author(s):  
Luisa Capalbo ◽  
Emilie Montembault ◽  
Tetsuya Takeda ◽  
Zuni I. Bassi ◽  
David M. Glover ◽  
...  
Keyword(s):  
Cell Division ◽  
Molecular Basis ◽  
Cleavage Site ◽  
Human Cells ◽  
Membrane Association ◽  
Aurora B ◽  
Chromosomal Passenger Complex ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Chromosomal Passenger

Summary Cytokinesis controls the proper segregation of nuclear and cytoplasmic materials at the end of cell division. The chromosomal passenger complex (CPC) has been proposed to monitor the final separation of the two daughter cells at the end of cytokinesis in order to prevent cell abscission in the presence of DNA at the cleavage site, but the precise molecular basis for this is unclear. Recent studies indicate that abscission could be mediated by the assembly of filaments comprising components of the endosomal sorting complex required for transport-III (ESCRT-III). Here, we show that the CPC subunit Borealin interacts directly with the Snf7 components of ESCRT-III in both Drosophila and human cells. Moreover, we find that the CPC's catalytic subunit, Aurora B kinase, phosphorylates one of the three human Snf7 paralogues—CHMP4C—in its C-terminal tail, a region known to regulate its ability to form polymers and associate with membranes. Phosphorylation at these sites appears essential for CHMP4C function because their mutation leads to cytokinesis defects. We propose that CPC controls abscission timing through inhibition of ESCRT-III Snf7 polymerization and membrane association using two concurrent mechanisms: interaction of its Borealin component with Snf7 proteins and phosphorylation of CHMP4C by Aurora B.

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.

scholarly journals A conserved subcomplex within the bacterial cytokinetic ring activates cell wall synthesis by the FtsW-FtsI synthase

2020 ◽  
Vol 117 (38) ◽  
pp. 23879-23885 ◽  
Author(s):  
Lindsey S. Marmont ◽  
Thomas G. Bernhardt
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Cell Division ◽  
Polymerase Activity ◽  
Bacterial Cell Division ◽  
Cell Wall Synthesis ◽  
Negative Regulators ◽  
Major Function ◽  
Osmotic Lysis ◽  
Direct Activator

Cell division in bacteria is mediated by a multiprotein assembly called the divisome. A major function of this machinery is the synthesis of the peptidoglycan (PG) cell wall that caps the daughter poles and prevents osmotic lysis of the newborn cells. Recent studies have implicated a complex of FtsW and FtsI (FtsWI) as the essential PG synthase within the divisome; however, how PG polymerization by this synthase is regulated and coordinated with other activities within the machinery is not well understood. Previous results have implicated a conserved subcomplex of division proteins composed of FtsQ, FtsL, and FtsB (FtsQLB) in the regulation of FtsWI, but whether these proteins act directly as positive or negative regulators of the synthase has been unclear. To address this question, we purified a five-memberPseudomonas aeruginosadivision complex consisting of FtsQLB-FtsWI. The PG polymerase activity of this complex was found to be greatly stimulated relative to FtsWI alone. Purification of complexes lacking individual components indicated that FtsL and FtsB are sufficient for FtsW activation. Furthermore, support for this activity being important for the cellular function of FtsQLB was provided by the identification of two division-defective variants of FtsL that still form normal FtsQLB-FtsWI complexes but fail to activate PG synthesis. Thus, our results indicate that the conserved FtsQLB complex is a direct activator of PG polymerization by the FtsWI synthase and thereby define an essential regulatory step in the process of bacterial cell division.

scholarly journals Asymmetric localization of the cell division machinery during Bacillus subtilis sporulation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Kanika Khanna ◽  
Javier Lopez Garrido ◽  
Joseph Sugie ◽  
Kit Pogliano ◽  
Elizabeth Villa
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Mother Cell ◽  
Electron Tomography ◽  
Leading Edge ◽  
Specific Protein ◽  
Bacterial Cell Division ◽  
Daughter Cells ◽  
Septal Thickness ◽  
Cryo Electron Tomography

The Gram-positive bacterium Bacillus subtilis can divide via two modes. During vegetative growth, the division septum is formed at the midcell to produce two equal daughter cells. However, during sporulation, the division septum is formed closer to one pole to yield a smaller forespore and a larger mother cell. Using cryo-electron tomography, genetics and fluorescence microscopy, we found that the organization of the division machinery is different in the two septa. While FtsAZ filaments, the major orchestrators of bacterial cell division, are present uniformly around the leading edge of the invaginating vegetative septa, they are only present on the mother cell side of the invaginating sporulation septa. We provide evidence suggesting that the different distribution and number of FtsAZ filaments impact septal thickness, causing vegetative septa to be thicker than sporulation septa already during constriction. Finally, we show that a sporulation-specific protein, SpoIIE, regulates asymmetric divisome localization and septal thickness during sporulation.

scholarly journals NO-stressed Y. pseudotuberculosis have decreased cell division rates in the mouse spleen

2021 ◽  
Author(s):  
Bessie Liu ◽  
Robert K Davidson ◽  
Kimberly Michele Davis
Keyword(s):  
Cell Division ◽  
Yersinia Pseudotuberculosis ◽  
Fluorescent Protein ◽  
Spatial Location ◽  
Mouse Spleen ◽  
Post Inoculation ◽  
Bacterial Cell Division ◽  
Bacterial Populations ◽  
Daughter Cells ◽  
Host Tissues

Fluorescence dilution approaches can detect bacterial cell division events, and can detect if there are differential rates of cell division across individual cells within a population. This approach typically involves inducing expression of a fluorescent protein, and then tracking partitioning of fluorescence into daughter cells. However, fluorescence can be diluted very quickly within a rapidly replicating population, such as pathogenic bacterial populations replicating within host tissues. To overcome this limitation, we have generated a revTetR reporter construct, where mCherry is constitutively expressed, and repressed by addition of tetracyclines, resulting in fluorescence dilution within defined timeframes. We show that mCherry signal is diluted in replicating populations, and that mCherry signal accumulates in growth-inhibited populations, including during exposure to inhibitory concentrations of antibiotics and during nitric oxide exposure. Furthermore, we show that tetracyclines can be delivered to the mouse spleen during Yersinia pseudotuberculosis infection. We defined a drug concentration that results in even exposure of cells to tetracyclines, and used this system to visualize cell division within defined timeframes post-inoculation. revTetR mCherry signal did not appear enriched in a particular spatial location within replicating centers of bacteria. However, the addition of a NO-sensing reporter (Phmp::gfp) showed that heightened NO exposure correlated with heightened mCherry signal, suggesting decreased cell division within this subpopulation. This revTetR reporter will provide a critical tool for future studies to identify and isolate slowly replicating bacterial subpopulations from host tissues.

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