scholarly journals SEDS-bPBP pairs direct Lateral and Septal Peptidoglycan Synthesis in Staphylococcus aureus

2019 ◽  
Author(s):  
Nathalie T. Reichmann ◽  
Andreia C. Tavares ◽  
Bruno M. Saraiva ◽  
Ambre Jousselin ◽  
Patricia Reed ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Late Stage ◽  
Cell Elongation ◽  
Cell Shape ◽  
Protein A ◽  
Interacting Proteins ◽  
Peptidoglycan Synthesis ◽  
Multiple Rings

Peptidoglycan (PGN) is the major component of the bacterial cell wall, a structure essential for the physical integrity and shape of the cell. Bacteria maintain cell shape by directing PGN incorporation to distinct regions of the cell, namely through the localisation of the late stage PGN synthesis proteins. These include two key protein families, SEDS transglycosylases and the bPBP transpeptidases, proposed to function in cognate pairs. Rod-shaped bacteria have two SEDS-bPBP pairs, involved in cell elongation and cell division. Here, we elucidate why coccoid bacteria, such as Staphylococcus aureus, also possess two SEDS-bPBP pairs. We determined that S. aureus RodA-PBP3 and FtsW-PBP1 likely constitute cognate pairs of interacting proteins. Lack of RodA-PBP3 decreased cell eccentricity due to deficient pre-septal PGN synthesis, whereas the depletion of FtsW-PBP1 arrested normal septal PGN incorporation. Although PBP1 is an essential protein, a mutant lacking PBP1 transpeptidase activity is viable, showing that this protein has a second function. We propose that the FtsW-PBP1 pair has a role in stabilising the divisome at midcell. In the absence of these proteins, the divisome appears as multiple rings/arcs that drive lateral PGN incorporation, leading to cell elongation. We conclude that RodA-PBP3 and FtsW-PBP1 mediate lateral and septal PGN incorporation, respectively, and that the activity of these pairs must be balanced in order to maintain coccoid morphology.

scholarly journals Bacterial Cell Wall Quality Control during Environmental Stress

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Elizabeth A. Mueller ◽  
Petra Anne Levin
Keyword(s):  
Quality Control ◽  
Cell Wall ◽  
Cell Surface ◽  
Environmental Stress ◽  
Environmental Conditions ◽  
Bacterial Cell ◽  
Cell Shape ◽  
Bacterial Cell Wall ◽  
Peptidoglycan Synthesis ◽  
Peptidoglycan Cell Wall

ABSTRACT Single-celled organisms must adapt their physiology to persist and propagate across a wide range of environmental conditions. The growth and division of bacterial cells depend on continuous synthesis of an essential extracellular barrier: the peptidoglycan cell wall, a polysaccharide matrix that counteracts turgor pressure and confers cell shape. Unlike many other essential processes and structures within the bacterial cell, the peptidoglycan cell wall and its synthesis machinery reside at the cell surface and are thus uniquely vulnerable to the physicochemical environment and exogenous threats. In addition to the diversity of stressors endangering cell wall integrity, defects in peptidoglycan metabolism require rapid repair in order to prevent osmotic lysis, which can occur within minutes. Here, we review recent work that illuminates mechanisms that ensure robust peptidoglycan metabolism in response to persistent and acute environmental stress. Advances in our understanding of bacterial cell wall quality control promise to inform the development and use of antimicrobial agents that target the synthesis and remodeling of this essential macromolecule. IMPORTANCE Nearly all bacteria are encased in a peptidoglycan cell wall, an essential polysaccharide structure that protects the cell from osmotic rupture and reinforces cell shape. The integrity of this protective barrier must be maintained across the diversity of environmental conditions wherein bacteria replicate. However, at the cell surface, the cell wall and its synthesis machinery face unique challenges that threaten their integrity. Directly exposed to the extracellular environment, the peptidoglycan synthesis machinery encounters dynamic and extreme physicochemical conditions, which may impair enzymatic activity and critical protein-protein interactions. Biotic and abiotic stressors—including host defenses, cell wall active antibiotics, and predatory bacteria and phage—also jeopardize peptidoglycan integrity by introducing lesions, which must be rapidly repaired to prevent cell lysis. Here, we review recently discovered mechanisms that promote robust peptidoglycan synthesis during environmental and acute stress and highlight the opportunities and challenges for the development of cell wall active therapeutics.

scholarly journals Daptomycin Exerts Bactericidal Activity without Lysis of Staphylococcus aureus

2008 ◽  
Vol 52 (6) ◽  
pp. 2223-2225 ◽  
Author(s):  
Nicole Cotroneo ◽  
Robert Harris ◽  
Nancy Perlmutter ◽  
Terry Beveridge ◽  
Jared A. Silverman
Keyword(s):  
Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Bactericidal Activity ◽  
Membrane Integrity ◽  
Cell Lysis

ABSTRACT The ability of daptomycin to produce bactericidal activity against Staphylococcus aureus while causing negligible cell lysis has been demonstrated using electron microscopy and the membrane integrity probes calcein and ToPro3. The formation of aberrant septa on the cell wall, suggestive of impairment of the cell division machinery, was also observed.

scholarly journals Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Elizaveta Krol ◽  
Hamish C. L. Yau ◽  
Marcus Lechner ◽  
Simon Schäper ◽  
Gert Bange ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Growth ◽  
Cell Elongation ◽  
Sinorhizobium Meliloti ◽  
Rgs Proteins ◽  
Polar Growth ◽  
Content Type ◽  
Cell Pole ◽  
Growing Cell

ABSTRACT Sinorhizobium meliloti is an alphaproteobacterium belonging to the Rhizobiales. Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal, and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ, and Pal localized to the growing cell pole in the cell elongation phase and to the septum in predivisional cells, and three Rgs proteins localized to the growing cell pole only. The putative FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of the Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other alphaproteobacterial orders, suggesting a conserved role of these proteins in polar growth. IMPORTANCE Bacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod-shaped bacteria is cell elongation by incorporating new peptidoglycans in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the alphaproteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales. Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

scholarly journals The first report on the sortase-mediated display of bioactive protein A from Staphylococcus aureus (SpA) on the surface of the vegetative form of Bacillus subtilis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Samira Ghaedmohammadi ◽  
Gholamreza Ahmadian
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Bacillus Subtilis ◽  
Binding Capacity ◽  
Surface Display ◽  
Protein A ◽  
Production Costs ◽  
Rabbit Serum ◽  
Experimental Conditions ◽  
Binding Domains

AbstractProtein A (SpA) is one of the most important Staphylococcus aureus cell wall proteins. It includes five immunoglobulin (Ig)-binding domains which can bind to immune complexes through the Fc region of immunoglobulins. The binding of SpA to the polymeric supports can be used to prepare affinity chromatography resins, which are useful for immunoprecipitation (IP) of antibodies. Protein A is also used to purify many anti-cancer antibodies. In this study, SpA was displayed on the surface of Bacillus subtilis cells using a sortase-mediated system to display the target protein to the B. subtilis cell wall. A series of plasmids consisting of cassettes for cell wall-directed protein A as well as negative controls were constructed and transformed into B. subtilis WASD (wprA sigD) cells. SDS-PAGE, western blot, flow cytometry, functional IgG purification assay, and a modified ELISA assay were used to confirm the surface display of SpA and evaluate its function. Semi-quantitative ELISA results showed that the binding capacity of lyophilized Bs-SpA is 100 μg IgG from rabbit serum per 1 mg of cells under optimal experimental conditions. Low production costs, optimal performance, and the use of a harmless strain compared to a similar commercial product predict the possible use of SpA immobilization technology in the future.

scholarly journals Release of protein A from the cell wall of Staphylococcus aureus

2014 ◽  
Vol 111 (4) ◽  
pp. 1574-1579 ◽  
Author(s):  
S. Becker ◽  
M. B. Frankel ◽  
O. Schneewind ◽  
D. Missiakas
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Protein A

scholarly journals DivIVA Is Required for Polar Growth in the MreB-Lacking Rod-Shaped Actinomycete Corynebacterium glutamicum

2008 ◽  
Vol 190 (9) ◽  
pp. 3283-3292 ◽  
Author(s):  
Michal Letek ◽  
Efrén Ordóñez ◽  
José Vaquera ◽  
William Margolin ◽  
Klas Flärdh ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Corynebacterium Glutamicum ◽  
Chromosome Segregation ◽  
Polar Growth ◽  
Cell Wall Synthesis ◽  
Peptidoglycan Synthesis ◽  
Polarized Cell Growth

ABSTRACT The actinomycete Corynebacterium glutamicum grows as rod-shaped cells by zonal peptidoglycan synthesis at the cell poles. In this bacterium, experimental depletion of the polar DivIVA protein (DivIVACg) resulted in the inhibition of polar growth; consequently, these cells exhibited a coccoid morphology. This result demonstrated that DivIVA is required for cell elongation and the acquisition of a rod shape. DivIVA from Streptomyces or Mycobacterium localized to the cell poles of DivIVACg-depleted C. glutamicum and restored polar peptidoglycan synthesis, in contrast to DivIVA proteins from Bacillus subtilis or Streptococcus pneumoniae, which localized at the septum of C. glutamicum. This confirmed that DivIVAs from actinomycetes are involved in polarized cell growth. DivIVACg localized at the septum after cell wall synthesis had started and the nucleoids had already segregated, suggesting that in C. glutamicum DivIVA is not involved in cell division or chromosome segregation.

scholarly journals The Staphylococcus aureus Methicillin Resistance Factor FmtA Is a d-Amino Esterase That Acts on Teichoic Acids

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Muhammad M. Rahman ◽  
Howard N. Hunter ◽  
Shamina Prova ◽  
Vidhu Verma ◽  
Aneela Qamar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Division ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Negative Charge ◽  
Methicillin Resistance ◽  
Teichoic Acid ◽  
Teichoic Acids ◽  
Phosphate Backbone

ABSTRACT The methicillin resistance factor encoded by fmtA is a core member of the Staphylococcus aureus cell wall stimulon, but its function has remained elusive for the past two decades. First identified as a factor that affects methicillin resistance in S. aureus strains, FmtA was later shown to interact with teichoic acids and to localize to the cell division septum. We have made a breakthrough in understanding FmtA function. We show that FmtA hydrolyzes the ester bond between d -Ala and the backbone of teichoic acids, which are polyglycerol-phosphate or polyribitol-phosphate polymers found in the S. aureus cell envelope. FmtA contains two conserved motifs found in serine active-site penicillin-binding proteins (PBPs) and β-lactamases. The conserved SXXK motif was found to be important for the d -amino esterase activity of FmtA. Moreover, we show that deletion of fmtA (Δ fmtA ) led to higher levels of d -Ala in teichoic acids, and this effect was reversed by complementation of Δ fmtA with fmtA . The positive charge on d -Ala partially masks the negative charge of the polyol-phosphate backbone of teichoic acids; hence, a change in the d -Ala content will result in modulation of their charge. Cell division, biofilm formation, autolysis, and colonization are among the many processes in S. aureus affected by the d -Ala content and overall charge of the cell surface teichoic acids. The esterase activity of FmtA and the regulation of fmtA suggest that FmtA functions as a modulator of teichoic acid charge, thus FmtA may be involved in S. aureus cell division, biofilm formation, autolysis, and colonization. IMPORTANCE Teichoic acids are involved in cell division, cell wall synthesis, biofilm formation, attachment of bacteria to artificial surfaces, and colonization. However, the function of teichoic acids is not fully understood. Modification by glycosylation and/or d -alanylation of the polyol-phosphate backbone of teichoic acids is important in the above cell processes. The intrinsic negative charge of teichoic acid backbone plays a role in the charge and/or pH of the bacterial surface, and d -alanylation represents a means through which bacteria modulate the charge or the pH of their surfaces. We discovered that FmtA removes d -Ala from teichoic acids. We propose FmtA may provide a temporal and spatial regulation of the bacterial cell surface charge in two ways, by removing the d -Ala from LTA to make it available to wall teichoic acid (WTA) in response to certain conditions and by removing it from WTA to allow the cell to reset its surface charge to a previous condition.

scholarly journals Distribution of Protein A on the Surface of Staphylococcus aureus

2007 ◽  
Vol 189 (12) ◽  
pp. 4473-4484 ◽  
Author(s):  
Andrea C. DeDent ◽  
Molly McAdow ◽  
Olaf Schneewind
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Laser Scanning ◽  
Protein A ◽  
Surface Proteins ◽  
Laser Scanning Microscopy ◽  
Subsequent Growth ◽  
Cross Bridges ◽  
Human Infections ◽  
Chemical Linkage

ABSTRACT Surface proteins of Staphylococcus aureus fulfill many important roles during the pathogenesis of human infections and are anchored to the cell wall envelope by sortases. Although the chemical linkage of proteins to cell wall cross bridges is known, the mechanisms whereby polypeptides are distributed on the staphylococcal surface have not been revealed. We show here that protein A, the ligand of immunoglobulin, is unevenly distributed over the staphylococcal surface. Upon removal with trypsin, newly synthesized polypeptide is deposited at two to four discrete foci. During subsequent growth, protein A appears to be slowly distributed from these sites. When viewed through multiple focal planes by laser scanning microscopy, protein A foci are arranged in a circle surrounding the bacterial cell. This pattern of distribution requires the LPXTG sorting signal of protein A as well as sortase A, the transpeptidase that anchors polypeptides to cell wall cross bridges. A model is presented whereby protein A deposition at discrete sites coupled with cell wall synthesis enables distribution of protein A on the staphylococcal surface.

scholarly journals Global Virulence Regulation in Staphylococcus aureus: Pinpointing the Roles of ClpP and ClpX in the sar/agr Regulatory Network

2005 ◽  
Vol 73 (12) ◽  
pp. 8100-8108 ◽  
Author(s):  
Dorte Frees ◽  
Karen Sørensen ◽  
Hanne Ingmer
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Regulatory Network ◽  
Protein A ◽  
Independent Effect ◽  
Large Set ◽  
Fibrinogen Binding ◽  
Superficial Wound ◽  
Life Threatening ◽  
Systemic Infections

ABSTRACT Staphylococcus aureus causes infections ranging from superficial wound infections to life-threatening systemic infections. Essential for S. aureus pathogenicity are a number of cell-wall-associated and secreted proteins that are controlled by a complex regulatory network involving the quorum-sensing agr locus and a large set of transcription factors belonging to the Sar family. Recently, we revealed a new layer of regulation by showing that mutants lacking the ClpXP protease produce reduced amounts of several extracellular virulence factors and that, independently of ClpP, ClpX is required for transcription of spa, encoding Protein A. Here we find that the independent effect of ClpX is not general for other cell wall proteins, as expression of fibronectin- and fibrinogen-binding proteins was increased in the absence of either ClpX or ClpP. To assess the roles of ClpX and ClpP within the sar/agr regulatory network, deletions in clpX and clpP were combined with mutations in these genes. Interestingly, the derepression of spa transcription normally observed in an agr-negative strain was abolished in cells devoid of ClpX, and apparently ClpX modulates both SarS-dependent and SarS-independent control of spa expression, perhaps through the Sar family member Rot. Examination of expression of a single secreted protein, the SspA serine protease, revealed that ClpXP, similar to agr, is required for growth phase-dependent transcriptional induction of sspa. Intriguingly, induction was restored by the concomitant inactivation of Rot. We hypothesize that RNAIII accumulating in the postexponential phase may target Rot for degradation by ClpXP, leading to derepression of sspA.

scholarly journals Molecular networks linked by Moesin drive remodeling of the cell cortex during mitosis

2011 ◽  
Vol 195 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Chantal Roubinet ◽  
Barbara Decelle ◽  
Gaëtan Chicanne ◽  
Jonas F. Dorn ◽  
Bernard Payrastre ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Elongation ◽  
Cell Shape ◽  
Mitotic Cell ◽  
Molecular Networks ◽  
Cell Cortex ◽  
Anaphase Onset ◽  
Shape Transformations ◽  
Intracellular Pressure ◽  
Early Mitosis

The cortical mechanisms that drive the series of mitotic cell shape transformations remain elusive. In this paper, we identify two novel networks that collectively control the dynamic reorganization of the mitotic cortex. We demonstrate that Moesin, an actin/membrane linker, integrates these two networks to synergize the cortical forces that drive mitotic cell shape transformations. We find that the Pp1-87B phosphatase restricts high Moesin activity to early mitosis and down-regulates Moesin at the polar cortex, after anaphase onset. Overactivation of Moesin at the polar cortex impairs cell elongation and thus cytokinesis, whereas a transient recruitment of Moesin is required to retract polar blebs that allow cortical relaxation and dissipation of intracellular pressure. This fine balance of Moesin activity is further adjusted by Skittles and Pten, two enzymes that locally produce phosphoinositol 4,5-bisphosphate and thereby, regulate Moesin cortical association. These complementary pathways provide a spatiotemporal framework to explain how the cell cortex is remodeled throughout cell division.

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