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Pore forming toxins

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https://www.readbyqxmd.com/read/28420883/leukocidins-staphylococcal-bi-component-pore-forming-toxins-find-their-receptors
#1
REVIEW
András N Spaan, Jos A G van Strijp, Victor J Torres
Staphylococcus aureus is a major bacterial pathogen that causes disease worldwide. The emergence of strains that are resistant to commonly used antibiotics and the failure of vaccine development have resulted in a renewed interest in the pathophysiology of this bacterium. Staphylococcal leukocidins are a family of bi-component pore-forming toxins that are important virulence factors. During the past five years, cellular receptors have been identified for all of the bi-component leukocidins. The identification of the leukocidin receptors explains the cellular tropism and species specificity that is exhibited by these toxins, which has important biological consequences...
April 19, 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28396322/camp-elevating-capacity-of-the-adenylate-cyclase-toxin-hemolysin-is-sufficient-for-lung-infection-but-not-for-full-virulence-of-bordetella-pertussis
#2
Karolina Skopova, Barbora Tomalova, Ivan Kanchev, Pavel Rossmann, Martina Svedova, Irena Adkins, Ilona Bibova, Jakub Tomala, Jiri Masin, Nicole Guiso, Radim Osicka, Radislav Sedlacek, Marek Kovar, Peter Sebo
The adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) of Bordetella pertussis targets phagocytic cells expressing the complement receptor 3 (CR3, Mac-1, αMβ2 integrin or CD11b/CD18). CyaA delivers into cells an N-terminal adenylyl cyclase (AC) enzyme domain that is activated by cytosolic calmodulin and catalyzes unregulated conversion of cellular ATP into cAMP, a key second messenger subverting bactericidal activities of phagocytes. In parallel, the hemolysin (Hly) moiety of CyaA forms cation-selective hemolytic pores that permeabilize target cell membranes...
April 10, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28396016/differential-binding-and-activity-of-the-pore-forming-toxin-sticholysin-ii-in-model-membranes-containing-diverse-ceramide-derived-lipids
#3
Carmen Soto, Anaixis Del Valle, Pedro A Valiente, Uris Ros, María E Lanio, Ana M Hernández, Carlos Alvarez
Sticholysin II is a pore-forming toxin produced by the sea anemone Stichodactyla helianthus that belongs to the actinoporin protein family. The high affinity of actinoporins for sphingomyelin (SM)-containing membranes has been well documented. However, the molecular determinants that define this affinity have not been fully clarified. Here, we have examined the binding and permeabilizing activity of StII to different single and mixed lipidic systems by combining lipid monolayers, liposomes, and permeabilizing assays...
April 7, 2017: Biochimie
https://www.readbyqxmd.com/read/28387756/pore-forming-toxin-mediated-ion-dysregulation-leads-to-death-receptor-independent-necroptosis-of-lung-epithelial-cells-during-bacterial-pneumonia
#4
Norberto González-Juarbe, Kelley Margaret Bradley, Anukul Taranath Shenoy, Ryan Paul Gilley, Luis Felipe Reyes, Cecilia Anahí Hinojosa, Marcos Ignacio Restrepo, Peter Herman Dube, Molly Ann Bergman, Carlos Javier Orihuela
We report that pore-forming toxins (PFTs) induce respiratory epithelial cell necroptosis independently of death receptor signaling during bacterial pneumonia. Instead, necroptosis was activated as a result of ion dysregulation arising from membrane permeabilization. PFT-induced necroptosis required RIP1, RIP3 and MLKL, and could be induced in the absence or inhibition of TNFR1, TNFR2 and TLR4 signaling. We detected activated MLKL in the lungs from mice and nonhuman primates experiencing Serratia marcescens and Streptococcus pneumoniae pneumonia, respectively...
April 7, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28382496/molecular-evolutionary-constraints-that-determine-the-avirulence-state-of-clostridium-botulinum-c2-toxin
#5
A Prisilla, R Prathiviraj, P Chellapandi
Clostridium botulinum (group-III) is an anaerobic bacterium producing C2 toxin along with botulinum neurotoxins. C2 toxin is belonged to binary toxin A family in bacterial ADP-ribosylation superfamily. A structural and functional diversity of binary toxin A family was inferred from different evolutionary constraints to determine the avirulence state of C2 toxin. Evolutionary genetic analyses revealed evidence of C2 toxin cluster evolution through horizontal gene transfer from the phage or plasmid origins, site-specific insertion by gene divergence, and homologous recombination event...
April 5, 2017: Journal of Molecular Evolution
https://www.readbyqxmd.com/read/28379176/ostreolysin-a-pleurotolysin-b-and-equinatoxins-structure-function-and-pathophysiological-effects-of-these-pore-forming-proteins
#6
REVIEW
Robert Frangež, Dušan Šuput, Jordi Molgó, Evelyne Benoit
Acidic ostreolysin A/pleurotolysin B (OlyA/PlyB, formerly known as ostreolysin (Oly), and basic 20 kDa equinatoxins (EqTs) are cytolytic proteins isolated from the edible mushroom Pleurotus ostreatus and the sea anemone Actinia equina, respectively. Both toxins, although from different sources, share many similar biological activities: (i) colloid-osmotic shock by forming pores in cellular and artificial membranes enriched in cholesterol and sphingomyelin; (ii) increased vascular endothelial wall permeability in vivo and perivascular oedema; (iii) dose-dependent contraction of coronary vessels; (iv) haemolysis with pronounced hyperkalaemia in vivo; (v) bradycardia, myocardial ischemia and ventricular extrasystoles accompanied by progressive fall of arterial blood pressure and respiratory arrest in rodents...
April 5, 2017: Toxins
https://www.readbyqxmd.com/read/28373868/morin-attenuates-streptococcus-suis-pathogenicity-in-mice-by-neutralizing-suilysin-activity
#7
Gen Li, Gejin Lu, Zhimin Qi, Hongen Li, Lin Wang, Yanhui Wang, Bowen Liu, Xiaodi Niu, Xuming Deng, Jianfeng Wang
Streptococcus suis, a Gram-positive pathogen, is widely recognized as an important agent of swine infection, and it is also known to cause a variety of zoonoses, such as meningitis, polyarthritis and pneumonia. Suilysin (SLY), an extracellular pore-forming toxin that belongs to the cholesterol-dependent cytolysin family, is an essential virulence factor of S. suis capsular type 2 (SS2). Here, we found that morin hydrate (morin), a natural flavonoid that lacks anti-SS2 activity, inhibits the hemolytic activity of SLY, protects J774 cells from SS2-induced injury and protects mice from SS2 infection...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28344124/comparative-genomics-of-transport-proteins-in-probiotic-and-pathogenic-escherichia-coli-and-salmonella-enterica-strains
#8
Jimmy Do, Hassan Zafar, Milton H Saier
Escherichia coli is a genetically diverse species that can be pathogenic, probiotic, commensal, or a harmless laboratory strain. Pathogenic strains of E. coli cause urinary tract infections, diarrhea, hemorrhagic colitis, and pyelonephritis, while the two known probiotic E. coli strains combat inflammatory bowel disease and play a role in immunomodulation. Salmonella enterica, a close relative of E. coli, includes two important pathogenic serovars, Typhi and Typhimurium, causing typhoid fever and enterocolitis in humans, respectively, with the latter strain also causing a lethal typhoid fever-like disease in mice...
March 24, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28341807/the-human-cancer-cell-active-toxin-cry41aa-from-bacillus-thuringiensis-acts-like-its-insecticidal-counterparts
#9
Vidisha Krishnan, Barbara Domanska, Alicia Elhigazi, Fatai Afolabi, Michelle J West, Neil Crickmore
Understanding how certain protein toxins from the normally insecticidal bacterium Bacillus thuringiensis target human cell lines has implications for both the risk assessment of products containing these toxins and potentially for cancer therapy. This understanding requires knowledge of whether the human cell active toxins work by the same mechanism as their insecticidal counterparts or by alternative ones. The B. thuringiensis Cry41Aa (also known as Parasporin3) toxin is structurally related to the toxins synthesized by commercially produced transgenic insect-resistant plants, with the notable exception of an additional C-terminal beta-trefoil ricin domain...
March 24, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28323617/cryoem-structures-of-membrane-pore-and-prepore-complex-reveal-cytolytic-mechanism-of-pneumolysin
#10
Katharina van Pee, Alexander Neuhaus, Edoardo D'Imprima, Deryck J Mills, Werner Kühlbrandt, Özkan Yildiz
Many pathogenic bacteria produce pore-forming toxins to attack and kill human cells. We have determined the 4.5 Å structure of the ~2.2 MDa pore complex of pneumolysin, the main virulence factor of Streptococcus pneumoniae, by cryoEM. The pneumolysin pore is a 400 Å ring of 42 membrane-inserted monomers. Domain D3 of the soluble toxin refolds into two ~85 Å β-hairpins that traverse the lipid bilayer and assemble into a 168-strand β-barrel. The pore complex is stabilized by salt bridges between β-hairpins of adjacent subunits and an internal α-barrel...
March 21, 2017: ELife
https://www.readbyqxmd.com/read/28322888/pneumolysin-as-a-potential-therapeutic-target-in-severe-pneumococcal-disease
#11
REVIEW
Ronald Anderson, Charles Feldman
Acute pulmonary and cardiac injury remain significant causes of morbidity and mortality in those afflicted with severe pneumococcal disease, with the risk for early mortality often persisting several years beyond clinical recovery. Although remaining to be firmly established in the clinical setting, a considerable body of evidence, mostly derived from murine models of experimental infection, has implicated the pneumococcal, cholesterol-binding, pore-forming toxin, pneumolysin (Ply), in the pathogenesis of lung and myocardial dysfunction...
March 16, 2017: Journal of Infection
https://www.readbyqxmd.com/read/28304231/f199e-substitution-reduced-toxicity-of-clostridium-perfringens-epsilon-toxin-by-depriving-the-receptor-binding-capability
#12
Jingjing Kang, Jie Gao, Wenwu Yao, Lin Kang, Shan Gao, Hao Yang, Bin Ji, Ping Li, Jing Liu, Jiahao Yao, Wenwen Xin, Baohua Zhao, Jinglin Wang
Epsilon toxin (ETX), a potent toxin, is produced by types B and D strains of Clostridium perfringens, which could cause severe diseases in humans and domestic animals. Mutant rETX(F199E) was previously demonstrated to be a good vaccine candidate. However, the mechanism concerned remains unknown. To clarify how F199E substitution reduced ETX toxicity, we performed a series of experiments. The results showed that the cell-binding and pore-forming ability of rETX(F199E) was almost abolished. We speculated that F199E substitution reduced toxicity by depriving the receptor binding capability of ETX, which contributed to the hypothesis that domain I of ETX is responsible for cell binding...
March 17, 2017: Human Vaccines & Immunotherapeutics
https://www.readbyqxmd.com/read/28223456/a-natural-chimeric-pseudomonas-bacteriocin-with-novel-pore-forming-activity-parasitizes-the-ferrichrome-transporter
#13
Maarten G K Ghequire, Lieselore Kemland, Ernesto Anoz-Carbonell, Susan K Buchanan, René De Mot
Modular bacteriocins represent a major group of secreted protein toxins with a narrow spectrum of activity, involved in interference competition between Gram-negative bacteria. These antibacterial proteins include a domain for binding to the target cell and a toxin module at the carboxy terminus. Self-inhibition of producers is provided by coexpression of linked immunity genes that transiently inhibit the toxin's activity through formation of bacteriocin-immunity complexes or by insertion in the inner membrane, depending on the type of toxin module...
February 21, 2017: MBio
https://www.readbyqxmd.com/read/28196960/repair-of-a-bacterial-small-%C3%AE-barrel-toxin-pore-depends-on-channel-width
#14
Gisela von Hoven, Amable J Rivas, Claudia Neukirch, Martina Meyenburg, Qianqian Qin, Sapun Parekh, Nadja Hellmann, Matthias Husmann
Membrane repair emerges as an innate defense protecting target cells against bacterial pore-forming toxins. Here, we report the first paradigm of Ca(2+)-dependent repair following attack by a small β-pore-forming toxin, namely, plasmid-encoded phobalysin of Photobacterium damselae subsp. damselae In striking contrast, Vibrio cholerae cytolysin, the closest ortholog of phobalysin, subverted repair. Mutational analysis uncovered a role of channel width in toxicity and repair. Thus, the replacement of serine at phobalysin´s presumed channel narrow point with the bulkier tryptophan, the corresponding residue in Vibrio cholerae cytolysin (W318), modulated Ca(2+) influx, lysosomal exocytosis, and membrane repair...
February 14, 2017: MBio
https://www.readbyqxmd.com/read/28193196/rapid-eradication-of-colon-carcinoma-by-clostridium-perfringens-enterotoxin-suicidal-gene-therapy
#15
Jessica Pahle, Lutz Menzel, Nicole Niesler, Dennis Kobelt, Jutta Aumann, Maria Rivera, Wolfgang Walther
BACKGROUND: Bacterial toxins have evolved to an effective therapeutic option for cancer therapy. The Clostridium perfringens enterotoxin (CPE) is a pore-forming toxin with selective cytotoxicity. The transmembrane tight junction proteins claudin-3 and -4 are known high affinity CPE receptors. Their expression is highly upregulated in human cancers, including breast, ovarian and colon carcinoma. CPE binding to claudins triggers membrane pore complex formation, which leads to rapid cell death...
February 13, 2017: BMC Cancer
https://www.readbyqxmd.com/read/28186501/intrinsic-repair-protects-cells-from-pore-forming-toxins-by-microvesicle-shedding
#16
Matthew Romero, Michelle Keyel, Guilan Shi, Pushpak Bhattacharjee, Robyn Roth, John E Heuser, Peter A Keyel
Pore-forming toxins (PFTs) are used by both the immune system and by pathogens to disrupt cell membranes. Cells attempt to repair this disruption in various ways, but the exact mechanism(s) that cells use are not fully understood, nor agreed upon. Current models for membrane repair include (1) patch formation (e.g., fusion of internal vesicles with plasma membrane defects), (2) endocytosis of the pores, and (3) shedding of the pores by blebbing from the cell membrane. In this study, we sought to determine the specific mechanism(s) that cells use to resist three different cholesterol-dependent PFTs: Streptolysin O, Perfringolysin O, and Intermedilysin...
February 10, 2017: Cell Death and Differentiation
https://www.readbyqxmd.com/read/28176876/engineering-a-ph-responsive-pore-forming-protein
#17
Matic Kisovec, Saša Rezelj, Primož Knap, Miša Mojca Cajnko, Simon Caserman, Ajda Flašker, Nada Žnidaršič, Matej Repič, Janez Mavri, Yi Ruan, Simon Scheuring, Marjetka Podobnik, Gregor Anderluh
Listeriolysin O (LLO) is a cytolysin capable of forming pores in cholesterol-rich lipid membranes of host cells. It is conveniently suited for engineering a pH-governed responsiveness, due to a pH sensor identified in its structure that was shown before to affect its stability. Here we introduced a new level of control of its hemolytic activity by making a variant with hemolytic activity that was pH-dependent. Based on detailed structural analysis coupled with molecular dynamics and mutational analysis, we found that the bulky side chain of Tyr406 allosterically affects the pH sensor...
February 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28173991/damage-of-eukaryotic-cells-by-the-pore-forming-toxin-sticholysin-ii-consequences-of-the-potassium-efflux
#18
Sheila Cabezas, Sylvia Ho, Uris Ros, María E Lanio, Carlos Alvarez, F Gisou van der Goot
Pore-forming toxins (PFTs) form holes in membranes causing one of the most catastrophic damages to a target cell. Target organisms have evolved a regulated response against PFTs damage including cell membrane repair. This ability of cells strongly depends on the toxin concentration and the properties of the pores. It has been hypothesized that there is an inverse correlation between the size of the pores and the time required to repair the membrane, which has been for long a non-intuitive concept and far to be completely understood...
February 4, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28137589/participation-of-perforin-in-mediating-dopaminergic-neuron-loss-in-mptp-induced-parkinson-s-disease-in-mice
#19
Su-Ping Peng, Ye Zhang, Sjef Copray, Melitta Schachner, Yan-Qin Shen
Both resident innate and peripheral immune aberrations have been demonstrated to influence Parkinson's disease (PD) progression. However, it is still enigmatic how and which immune components are lethal to the dopaminergic neuron in PD. We now show that levels of perforin, a pore-forming protein expressed in cytotoxic immune cells, was significantly increased in the serum of wild-type mice 4 weeks after injection of MPTP, a toxin used to induce PD-like symptoms. We demonstrate that perforin-deficiency attenuated the acute striatal dopamine reduction by 33%, ablated microglia activation 3 days post MPTP-injection; and retarded dopaminergic neuron death 4 weeks post MPTP-injection...
March 11, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28128281/targeted-delivery-of-an-adp-ribosylating-bacterial-toxin-into-cancer-cells
#20
N-I Zahaf, A E Lang, L Kaiser, C D Fichter, S Lassmann, A McCluskey, A Augspach, K Aktories, G Schmidt
The actin cytoskeleton is an attractive target for bacterial toxins. The ADP-ribosyltransferase TccC3 from the insect bacterial pathogen Photorhabdus luminescence modifies actin to force its aggregation. We intended to transport the catalytic part of this toxin preferentially into cancer cells using a toxin transporter (Protective antigen, PA) which was redirected to Epidermal Growth Factor Receptors (EGFR) or to human EGF receptors 2 (HER2), which are overexpressed in several cancer cells. Protective antigen of anthrax toxin forms a pore through which the two catalytic parts (lethal factor and edema factor) or other proteins can be transported into mammalian cells...
January 27, 2017: Scientific Reports
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