scholarly journals Min waves without MinC can pattern FtsA-FtsZ filaments on model membranes

2021 ◽  
Author(s):  
Elisa Godino ◽  
Anne Doerr ◽  
Christophe Danelon
Keyword(s):  
Lipid Membranes ◽  
Essential Element ◽  
Minimal Set ◽  
Synthetic Cell ◽  
Membrane Tethering ◽  
Fresh Perspective ◽  
Z Ring ◽  
Free Gene

Although the essential proteins that drive bacterial cytokinesis have been identified and reconstituted in vitro, the precise mechanisms by which they dynamically interact to enable symmetrical division are largely unknown. In Escherichia coli, cell division begins with the formation of a proto-ring composed of FtsZ and its membrane-tethering proteins FtsA and ZipA. In the broadly proposed molecular scenario for ring positioning, Min waves composed of MinD and MinE distribute the FtsZ-polymerization inhibitor MinC away from mid-cell, where the Z-ring can form. Therefore, MinC is believed to be an essential element connecting the Min and FtsZ systems. Here, by using cell-free gene expression on planar lipid membranes, we demonstrate that MinDE drive the formation of dynamic, antiphase patterns of FtsZ-FtsA co-filaments even in the absence of MinC. This behavior is also observed when the proteins are compartmentalized inside microdroplets. These results suggest that Z-ring positioning may be achieved with a more minimal set of proteins than previously envisaged, providing a fresh perspective about the role of MinC. Moreover, we propose that MinDE oscillations may constitute the minimal localization mechanism of an FtsA-FtsZ constricting ring in a prospective synthetic cell.

Copper complexes as antitumor agents: in vitro and in vivo evidences

2021 ◽  
Vol 28 ◽  
Author(s):  
Lucia M. Balsa ◽  
Enrique J. Baran ◽  
Ignacio E. León
Keyword(s):  
Copper Complexes ◽  
Antitumor Agents ◽  
Essential Element ◽  
Design Synthesis ◽  
Copper Compounds ◽  
Comprehensive Knowledge ◽  
The Relationship

: Copper is an essential element for most aerobic organisms, with an important function as a structural and catalytic cofactor, and in consequence, it is implicated in several biological actions. The relevant aspects of chemistry and biochemistry and the importance of copper compounds in medicine give us a comprehensive knowledge of the multifaceted applications of copper in physiology and physiopathology. In this review, we present an outline of the chemistry and the antitumor properties of copper complexes on breast, colon, and lung cancer cells focus on the role of copper in cancer, the relationship between structure-activity, molecular targets, and the study of the mechanism of action involved in its anticancer activity. This overview is expected to contribute to understanding the design, synthesis, uses of copper complexes as antitumor agents in the most common cancers.

scholarly journals The Bacterial DNA Binding Protein MatP Involved in Linking the Nucleoid Terminal Domain to the Divisome at Midcell Interacts with Lipid Membranes

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Begoña Monterroso ◽  
Silvia Zorrilla ◽  
Marta Sobrinos-Sanguino ◽  
Miguel Ángel Robles-Ramos ◽  
Carlos Alfonso ◽  
...  
Keyword(s):  
Dna Binding ◽  
Dna Sequences ◽  
Lipid Membranes ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Content Type ◽  
E Coli ◽  
Daughter Cells ◽  
Z Ring

ABSTRACTDivision ring formation at midcell is controlled by various mechanisms inEscherichia coli, one of them being the linkage between the chromosomal Ter macrodomain and the Z-ring mediated by MatP, a DNA binding protein that organizes this macrodomain and contributes to the prevention of premature chromosome segregation. Here we show that, during cell division, just before splitting the daughter cells, MatP seems to localize close to the cytoplasmic membrane, suggesting that this protein might interact with lipids. To test this hypothesis, we investigated MatP interaction with lipidsin vitro. We found that, when encapsulated inside vesicles and microdroplets generated by microfluidics, MatP accumulates at phospholipid bilayers and monolayers matching the lipid composition in theE. coliinner membrane. MatP binding to lipids was independently confirmed using lipid-coated microbeads and biolayer interferometry assays, which suggested that the recognition is mainly hydrophobic. Interaction of MatP with the lipid membranes also occurs in the presence of the DNA sequences specifically targeted by the protein, but there is no evidence of ternary membrane/protein/DNA complexes. We propose that the association of MatP with lipids may modulate its spatiotemporal localization and its recognition of other ligands.IMPORTANCEThe division of anE. colicell into two daughter cells with equal genomic information and similar size requires duplication and segregation of the chromosome and subsequent scission of the envelope by a protein ring, the Z-ring. MatP is a DNA binding protein that contributes both to the positioning of the Z-ring at midcell and the temporal control of nucleoid segregation. Our integratedin vivoandin vitroanalysis provides evidence that MatP can interact with lipid membranes reproducing the phospholipid mixture in theE. coliinner membrane, without concomitant recruitment of the short DNA sequences specifically targeted by MatP. This observation strongly suggests that the membrane may play a role in the regulation of the function and localization of MatP, which could be relevant for the coordination of the two fundamental processes in which this protein participates, nucleoid segregation and cell division.

scholarly journals Essential Role of Ferritin Pfr in Helicobacter pylori Iron Metabolism and Gastric Colonization

2002 ◽  
Vol 70 (7) ◽  
pp. 3923-3929 ◽  
Author(s):  
Barbara Waidner ◽  
Stefan Greiner ◽  
Stefan Odenbreit ◽  
Holger Kavermann ◽  
Jyoti Velayudhan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Iron Metabolism ◽  
Essential Element ◽  
Iron Starvation ◽  
Iron Storage ◽  
Gastric Colonization ◽  
H Pylori ◽  
Iron Pool

ABSTRACT The reactivity of the essential element iron necessitates a concerted expression of ferritins, which mediate iron storage in a nonreactive state. Here we have further established the role of the Helicobacter pylori ferritin Pfr in iron metabolism and gastric colonization. Iron stored in Pfr enabled H. pylori to multiply under severe iron starvation and protected the bacteria from acid-amplified iron toxicity, as inactivation of the pfr gene restricted growth of H. pylori under these conditions. The lowered total iron content in the pfr mutant, which is probably caused by decreased iron uptake rates, was also reflected by an increased resistance to superoxide stress. Iron induction of Pfr synthesis was clearly diminished in an H. pylori feoB mutant, which lacked high-affinity ferrous iron transport, confirming that Pfr expression is mediated by changes in the cytoplasmic iron pool and not by extracellular iron. This is well in agreement with the recent discovery that iron induces Pfr synthesis by abolishing Fur-mediated repression of pfr transcription, which was further confirmed here by the observation that iron inhibited the in vitro binding of recombinant H. pylori Fur to the pfr promoter region. The functions of H. pylori Pfr in iron metabolism are essential for survival in the gastric mucosa, as the pfr mutant was unable to colonize in a Mongolian gerbil-based animal model. In summary, the pfr phenotypes observed give new insights into prokaryotic ferritin functions and indicate that iron storage and homeostasis are of extraordinary importance for H. pylori to survive in its hostile natural environment.

scholarly journals The structure of the Myo4p globular tail and its function in ASH1 mRNA localization

2010 ◽  
Vol 189 (3) ◽  
pp. 497-510 ◽  
Author(s):  
Alexander Heuck ◽  
Ingrid Fetka ◽  
Daniel N. Brewer ◽  
Daniela Hüls ◽  
Mary Munson ◽  
...  
Keyword(s):  
Mrna Localization ◽  
Surface Patch ◽  
X Ray ◽  
Membrane Tethering ◽  
Dividing Cells ◽  
Dependent Transport ◽  
Type V ◽  
Ash1 Mrna

Type V myosin (MyoV)–dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2–tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail–lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.

scholarly journals Bacterial dynamin-like protein DynA mediates lipid and content mixing and shows phospholipid specificity

2018 ◽  
Author(s):  
Lijun Guo ◽  
Marc Bramkamp
Keyword(s):  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Membrane Stress ◽  
Gtp Hydrolysis ◽  
Cellular Processes ◽  
Organelle Division ◽  
Membrane Tethering ◽  
Hydrolysis Of

ABSTRACTThe dynamins family of GTPases is involved in key cellular processes in eukaryotes, including vesicle trafficking and organelle division. The GTP hydrolysis cycle of dynamin translates to a conformational change in the protein structure, which forces the underlying lipid layer into an energetically unstable conformation that promotes membrane rearrangements. Many bacterial genomes encode dynamin-like proteins, but the biological function of these proteins has remained largely enigmatic. In recent years, our group has reported that the dynamin-like protein DynA from Bacillus subtilis mediates nucleotide-independent membrane tethering in vitro and contributes to the innate immunity of bacteria against membrane stress and phage infection. However, so far the mechanism of membrane stress response and the role of GTP hydrolysis remain unclear. Here, we employed content mixing and lipid mixing assays in reconstituted systems to study if the dynamin-like protein DynA from B. subtilis induces membrane full fusion, and further test the possibility that GTP hydrolysis of DynA may act on the fusion-through-hemifusion pathway. Our results based on fluorescence resonance energy transfer (FRET) indicated that DynA could induce aqueous content mixing even in absence of GTP. Moreover, DynA-induced membrane fusion in vitro is a thermo-promoted slow response. Surprisingly, digestion of protein mediated an instantl rise of content exchange, supporting the assumption that disassembly of DynA is the fundamental power for fusion-through-hemifusion.

scholarly journals Assembly of an FtsZ Mutant Deficient in GTPase Activity Has Implications for FtsZ Assembly and the Role of the Z Ring in Cell Division

2001 ◽  
Vol 183 (24) ◽  
pp. 7190-7197 ◽  
Author(s):  
Amit Mukherjee ◽  
Cristian Saez ◽  
Joe Lutkenhaus
Keyword(s):  
Cell Division ◽  
Critical Concentration ◽  
Gtpase Activity ◽  
Support Cell ◽  
Z Ring ◽  
Ftsz Assembly ◽  
The Stability

ABSTRACT FtsZ, the ancestral homologue of eukaryotic tubulins, assembles into the Z ring, which is required for cytokinesis in prokaryotic cells. Both FtsZ and tubulin have a GTPase activity associated with polymerization. Interestingly, the ftsZ2 mutant is viable, although the FtsZ2 mutant protein has dramatically reduced GTPase activity due to a glycine-for-aspartic acid substitution within the synergy loop. In this study, we have examined the properties of FtsZ2 and found that the reduced GTPase activity is not enhanced by DEAE-dextran-induced assembly, indicating it has a defective catalytic site. In the absence of DEAE-dextran, FtsZ2 fails to assemble unless supplemented with wild-type FtsZ. FtsZ has to be at or above the critical concentration for copolymerization to occur, indicating that FtsZ is nucleating the copolymers. The copolymers formed are relatively stable and appear to be stabilized by a GTP-cap. These results indicate that FtsZ2 cannot nucleate assembly in vitro, although it must in vivo. Furthermore, the stability of FtsZ-FtsZ2 copolymers argues that FtsZ2 polymers would be stable, suggesting that stable FtsZ polymers are able to support cell division.

scholarly journals The bacterial DNA binding protein MatP involved in linking the nucleoid terminal domain to the divisome at midcell interacts with lipid membranes

2018 ◽  
Author(s):  
Begoña Monterroso ◽  
Silvia Zorrilla ◽  
Marta Sobrinos-Sanguino ◽  
Miguel Ángel Robles-Ramos ◽  
Carlos Alfonso ◽  
...  
Keyword(s):  
Cell Division ◽  
Dna Binding ◽  
Dna Sequences ◽  
Lipid Membranes ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
E Coli ◽  
Daughter Cells ◽  
Z Ring

ABSTRACTDivision ring formation at midcell is controlled by various mechanisms inEscherichia coli, one of them being the linkage between the chromosomal Ter macrodomain and the Z-ring mediated by MatP, a DNA binding protein that organizes this macrodomain and contributes to the prevention of premature chromosome segregation. Here we show that, during cell division, just before splitting the daughter cells, MatP seems to localize close to the cytoplasmic membrane, suggesting that this protein might interact with lipids. To test this hypothesis, we investigated MatP interaction with lipidsin vitro. We found that MatP, when encapsulated inside microdroplets generated by microfluidics and giant vesicles, accumulates at phospholipid bilayers and monolayers matching the lipid composition in theE. coliinner membrane. MatP binding to lipids was independently confirmed using lipid coated microbeads and bio-layer interferometry assays. Interaction of MatP with the lipid membranes also occurs in the presence of the DNA sequences specifically targeted by the protein but there is no evidence of ternary membrane/protein/DNA complexes. We propose that the interaction of MatP with lipids may modulate its spatiotemporal localization and its recognition of other ligands.IMPORTANCEThe division of anE. colicell into two daughter cells with equal genomic information and similar size requires duplication and segregation of the chromosome and subsequent scission of the envelope by a protein ring, the Z-ring. MatP is a DNA binding protein that contributes both to the positioning of the Z-ring at midcell and the temporal control of nucleoid segregation. Our integratedin vivoandin vitroanalysis provides evidence that MatP can interact with lipid membranes comprising the phospholipid mixture in theE. coliinner membrane, without concomitant recruitment of the short DNA sequences specifically targeted by MatP. This observation strongly suggests that the membrane may play a role in the regulation of the function and localization of MatP, which could be relevant for the coordination of the two fundamental processes in which this protein participates, nucleoid segregation and cell division.

scholarly journals Development of an In Vitro Membrane Model to Study the Function of EsxAB Heterodimer and Establish the Role of EsxB in Membrane Permeabilizing Activity of Mycobacterium tuberculosis

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1015
Author(s):  
Salvador Vazquez Reyes ◽  
Supriyo Ray ◽  
Javier Aguilera ◽  
Jianjun Sun
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lipid Membranes ◽  
Effect Of Temperature ◽  
In Vitro Assays ◽  
Vitro Model ◽  
First Time ◽  
Dose Dependent Increase ◽  
Dose Dependent

EsxA and EsxB are secreted as a heterodimer and have been shown to play critical roles in phagosome rupture and translocation of Mycobacterium tuberculosis into the cytosol. Recent in vitro studies have suggested that the EsxAB heterodimer is dissociated upon acidification, which might allow EsxA insertion into lipid membranes. While the membrane permeabilizing activity (MPA) of EsxA has been well characterized in liposomes composed of di-oleoyl-phosphatidylcholine (DOPC), the MPA of EsxAB heterodimer has not been detected through in vitro assays due to its negligible activity with DOPC liposomes. In this study, we established a new in vitro membrane assay to test the MPA activity of N-terminal acetylated EsxA (N-EsxA). We established that a dose-dependent increase in anionic charged lipids enhances the MPA of N-EsxA. The MPA of both N-EsxA and EsxAB were significantly increased with this new liposome system and made it possible to characterize the MPA of EsxAB in more physiologically-relevant conditions. We tested, for the first time, the effect of temperature on the MPA of N-EsxA and EsxAB in this new system. Interestingly, the MPA of N-EsxA was lower at 37 °C than at RT, and on the contrary, the MPA of EsxAB was higher at 37 °C than at RT. Surprisingly, after incubation at 37 °C, the MPA of N-EsxA continuously decreased over time, while MPA of EsxAB remained stable, suggesting EsxB plays a key role in stabilizing N-EsxA to preserve its MPA at 37 °C. In summary, this study established a new in vitro model system that characterizes the MPA of EsxAB and the role of EsxB at physiological-relevant conditions.

scholarly journals WDPCP Modulates Cilia Beating Through the MAPK/ERK Pathway in Chronic Rhinosinusitis With Nasal Polyps

2021 ◽  
Vol 8 ◽  
Author(s):  
Yun Ma ◽  
Peng Tian ◽  
Hua Zhong ◽  
Fan Wu ◽  
Qining Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Chronic Rhinosinusitis ◽  
Nasal Polyp ◽  
Nasal Polyps ◽  
Essential Element ◽  
Nasal Epithelium ◽  
Erk Pathway ◽  
Low Expression

Cilia loss and dysfunction is one of the typical pathological features of chronic rhinosinusitis with nasal polyps (CRSwNP). Tryptophan-aspartic acid (W-D) repeat containing planar cell polarity effector (WDPCP) has been proven to be an essential element for ciliogenesis in human nasal epithelium, but its role in the beating of cilia remains unclear. In this study, we sought to investigate the role of WDPCP and its underlying mechanism behind the dysfunction in the beating of cilia in nasal polyp tissue. We demonstrated WDPCP expression in the epithelium of nasal polyps. We also investigated the MAPK/ERK pathway in primary human sinonasal epithelial cells to explore the function of WDPCP. The air–liquid interface culture system was used as a model to verify the role of WDPCP and the MAPK/ERK pathway in the beating of cilia. With the dysfunction of cilia beating, we observed a low expression of WDPCP in the epithelium of nasal polyp tissues. Within the in vitro study, we found that WDPCP was critical for mitochondrial biogenesis and mitochondrial function in human sinonasal epithelial cells, possibly due to the activation of the MAPK/ERK pathway. The mitochondrial dysfunction caused by U0126 or lacking WDPCP could be partially recovered by dexamethasone. The low expression of WDPCP in nasal epithelium could affect mitochondria via the MAPK/ERK pathway, which may contribute to the dysfunction in the beating of cilia in CRSwNP.

scholarly journals WDPCP modulates cilia beating through MAPK/ERK pathway in chronic rhinosinusitis

2020 ◽  
Author(s):  
Yun Ma ◽  
Peng Tian ◽  
Hua Zhong ◽  
Fan Wu ◽  
Qining Zhang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Chronic Rhinosinusitis ◽  
Nasal Polyps ◽  
Planar Cell Polarity ◽  
Essential Element ◽  
Nasal Epithelium ◽  
Erk Pathway ◽  
Low Expression

Abstract Background: Cilia loss and dysfunction is one of the typical pathological features of chronic rhinosinusitis. Tryptophan-aspartic acid (W-D) repeat containing planar cell polarity effector (WDPCP) has been proven to be an essential element for ciliogenesis in human nasal epithelium, but its role in the beating of cilia remains unclear. Cilia beating requires energy from the mitochondria, which is regulated by the MAPK/ERK pathway. In this study, we sought to investigate the role of WDPCP and its underlying mechanism behind the dysfunction in the beating of cilia in chronic rhinosinusitis.Methods: We demonstrated WDPCP expression in the epithelium of nasal polyps. We also investigated the MAPK/ERK pathway in primary human sinonasal epithelial cells to explore the function of WDPCP. The air-liquid interface culture system was used as a model to verify the role of WDPCP and the MAPK/ERK pathway in the beating of cilia.Results: With the dysfunction of cilia beating, we observed a low expression of WDPCP in the epithelium of nasal polyps. Within the in vitro study, we found that WDPCP was critical for mitochondrial biogenesis and mitochondrial function in human sinonasal epithelial cells, possibly due to the activation of the MAPK/ERK pathway. The mitochondrial dysfunction caused by U0126 or lacking WDPCP could be partially recovered by dexamethasone.Conclusion: The low expression of WDPCP in nasal epithelium could affect mitochondria via the MAPK/ERK pathway, which may contribute to the dysfunction in the beating of cilia in chronic rhinosinusitis.

Sign in / Sign up

Export Citation Format

Share Document