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Klaus Aktories - One of the best experts on this subject based on the ideXlab platform.
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the chaperonin tric cct is essential for the action of bacterial glycosylating Protein Toxins like clostridium difficile Toxins a and b
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Marcus Steinemann, Andreas Schlosser, Thomas Jank, Klaus AktoriesAbstract:Various bacterial Protein Toxins, including Clostridium difficile Toxins A (TcdA) and B (TcdB), attack intracellular target Proteins of host cells by glucosylation. After receptor binding and endocytosis, the Toxins are translocated into the cytosol, where they modify target Proteins (e.g., Rho Proteins). Here we report that the activity of translocated glucosylating Toxins depends on the chaperonin TRiC/CCT. The chaperonin subunits CCT4/5 directly interact with the Toxins and enhance the refolding and restoration of the glucosyltransferase activities of Toxins after heat treatment. Knockdown of CCT5 by siRNA and HSF1A, an inhibitor of TRiC/CCT, blocks the cytotoxic effects of TcdA and TcdB. In contrast, HSP90, which is involved in the translocation and uptake of ADP ribosylating Toxins, is not involved in uptake of the glucosylating Toxins. We show that the actions of numerous glycosylating Toxins from various toxin types and different species depend on TRiC/CCT. Our data indicate that the TRiC/CCT chaperonin system is specifically involved in toxin uptake and essential for the action of various glucosylating Protein Toxins acting intracellularly on target Proteins.
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The chaperonin TRiC/CCT is essential for the action of bacterial glycosylating Protein Toxins like Clostridium difficile Toxins A and B.
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Marcus Steinemann, Andreas Schlosser, Thomas Jank, Klaus AktoriesAbstract:Various bacterial Protein Toxins, including Clostridium difficile Toxins A (TcdA) and B (TcdB), attack intracellular target Proteins of host cells by glucosylation. After receptor binding and endocytosis, the Toxins are translocated into the cytosol, where they modify target Proteins (e.g., Rho Proteins). Here we report that the activity of translocated glucosylating Toxins depends on the chaperonin TRiC/CCT. The chaperonin subunits CCT4/5 directly interact with the Toxins and enhance the refolding and restoration of the glucosyltransferase activities of Toxins after heat treatment. Knockdown of CCT5 by siRNA and HSF1A, an inhibitor of TRiC/CCT, blocks the cytotoxic effects of TcdA and TcdB. In contrast, HSP90, which is involved in the translocation and uptake of ADP ribosylating Toxins, is not involved in uptake of the glucosylating Toxins. We show that the actions of numerous glycosylating Toxins from various toxin types and different species depend on TRiC/CCT. Our data indicate that the TRiC/CCT chaperonin system is specifically involved in toxin uptake and essential for the action of various glucosylating Protein Toxins acting intracellularly on target Proteins.
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ADP-Ribosylation and Cross-Linking of Actin by Bacterial Protein Toxins.
Handbook of experimental pharmacology, 2016Co-Authors: Klaus Aktories, Carsten Schwan, Alexander E. LangAbstract:Actin and the actin cytoskeleton play fundamental roles in host–pathogen interactions. Proper function of the actin cytoskeleton is crucial for innate and acquired immune defense. Bacterial Toxins attack the actin cytoskeleton by targeting regulators of actin. Moreover, actin is directly modified by various bacterial Protein Toxins and effectors, which cause ADP-ribosylation or cross-linking of actin. Modification of actin can result in inhibition or stimulation of actin polymerization. Toxins, acting directly on actin, are reviewed.
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Rho-modifying bacterial Protein Toxins
Pathogens and disease, 2015Co-Authors: Klaus AktoriesAbstract:Rho Proteins are targets of numerous bacterial Protein Toxins, which manipulate the GTP-binding Proteins by covalent modifications, including ADP ribosylation, glycosylation, adenylylation, proteolytic cleavage and deamidation. Bacterial Toxins are important virulence factors but are also potent and efficient pharmacological tools to study the physiological functions of their eukaryotic targets. Recent studies indicate that amazing variations exist in the molecular mechanisms by which Toxins attack Rho Proteins, which are discussed here.
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Bacterial Protein Toxins Acting on Small GTPases
Ras Superfamily Small G Proteins: Biology and Mechanisms 1, 2014Co-Authors: Klaus Aktories, Gudula SchmidtAbstract:Numerous bacterial Protein Toxins and effectors target eukaryotic cells by covalent modification of low molecular mass GTP-binding Proteins to manipulate their switch functions. Frequent targets are Rho, Ras, and Rab Proteins which are modified by ADP-ribosylation, adenylylation, mono-O-glycosylation, deamidation, transglutamination, phosphocholination, and proteolytic cleavage. Thereby, the GTPases are activated or inactivated. Other bacterial effectors manipulate the cellular functions of small GTPases by mimicking endogenous regulators of the switch Proteins. They act as guanine nucleotide exchange factors (GEFs) or GTPase-activating Proteins (GAPs). The chapter describes the bacterial Toxins and effectors and discusses the functional consequences of their actions.
Dev Vrat Kamboj - One of the best experts on this subject based on the ideXlab platform.
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Multiplex Detection of Protein Toxins Using MALDI-TOF-TOF Tandem Mass Spectrometry: Application in Unambiguous Toxin Detection from Bioaerosol
2016Co-Authors: Syed Imteyaz Alam, Bhoj Kumar, Dev Vrat KambojAbstract:Protein Toxins, such as botulinum neuroToxins (BoNTs), Clostridium perfringens epsilon toxin (ETX), staphylococcal enterotoxin B (SEB), shiga toxin (STX), and plant toxin ricin, are involved in a number of diseases and are considered as potential agents for bioterrorism and warfare. From a bioterrorism and warfare perspective, these agents are likely to cause maximum damage to a civilian or military population through an inhalational route of exposure and aerosol is considered the envisaged mode of delivery. Unambiguous detection of toxin from aerosol is of paramount importance, both for bringing mitigation protocols into operation and for implementation of effective medical countermeasures, in case a “biological cloud” is seen over a population. A multiplex, unambiguous, and qualitative detection of Protein Toxins is reported here using tandem mass spectrometry with MALDI-TOF-TOF. The methodology involving simple sample processing steps was demonstrated to identify Toxins (ETX, Clostridium perfringes phospholipase C, and SEB) from blind spiked samples. The novel directed search approach using a list of unique peptides was used to identify Toxins from a complex Protein mixture. The bioinformatic analysis of seven Protein Toxins for elucidation of unique peptides with conservation status across all known sequences provides a high confidence for detecting Toxins originating from any geographical location and source organism. Use of tandem MS data with peptide sequence information increases the specificity of the method. A prototype for generation of aerosol using a nebulizer and collection using a cyclone collector was used to provide a proof of concept for unambiguous detection of toxin from aerosol using precursor directed tandem mass spectrometry combined with Protein database searching. ETX prototoxin could be detected from aerosol at 0.2 ppb concentration in aerosol
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Multiplex detection of Protein Toxins using MALDI-TOF-TOF tandem mass spectrometry: application in unambiguous toxin detection from bioaerosol.
Analytical chemistry, 2012Co-Authors: Syed Imteyaz Alam, Bhoj Kumar, Dev Vrat KambojAbstract:Protein Toxins, such as botulinum neuroToxins (BoNTs), Clostridium perfringens epsilon toxin (ETX), staphylococcal enterotoxin B (SEB), shiga toxin (STX), and plant toxin ricin, are involved in a number of diseases and are considered as potential agents for bioterrorism and warfare. From a bioterrorism and warfare perspective, these agents are likely to cause maximum damage to a civilian or military population through an inhalational route of exposure and aerosol is considered the envisaged mode of delivery. Unambiguous detection of toxin from aerosol is of paramount importance, both for bringing mitigation protocols into operation and for implementation of effective medical countermeasures, in case a “biological cloud” is seen over a population. A multiplex, unambiguous, and qualitative detection of Protein Toxins is reported here using tandem mass spectrometry with MALDI-TOF-TOF. The methodology involving simple sample processing steps was demonstrated to identify Toxins (ETX, Clostridium perfringes pho...
Cesare Montecucco - One of the best experts on this subject based on the ideXlab platform.
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Cell Vesicle Trafficking and Bacterial Protein Toxins
Lipid and Protein Traffic, 1998Co-Authors: Cesare MontecuccoAbstract:Eukaryotic cells are characterized by an intense trafficking of Proteins, peptides and chemicals in and out of the cell as well as by trafficking within the various cell organelles. A group of bacterial Protein Toxins interfere with vesicular trafficking inside cells. Clostridial neuroToxins affect mainly the highly regulated fusion of neurotransmitter and hormones containing vesicles with the plasma membrane. They cleave the three SNARE Proteins: VAMP, SNAP-25 and syntaxin, and this selective proteolysis results in a blockade of exocytosis. The Helicobacter pylori cytotoxin is implicated in the pathogenesis of gastroduodenal ulcers. It causes a progressive and extensive vacuolation of cells followed by necrosis, consequent to a cytotoxin induced alteration of membrane trafficking at the level of late endosomes. Vacuoles origine from this compartment in a rab7 dependent process and swell because they are acidic and accumulate membrane permeant amines.
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Protein Toxins AND MEMBRANE TRANSPORT
Current opinion in cell biology, 1998Co-Authors: Cesare MontecuccoAbstract:Recently, Protein Toxins have provided novel information on the anatomy of the machinery that mediates vesicle docking and fusion with target membranes within the cell. Their use is being extended to the study of the physiology of these processes in different cells and tissues, as well as to the intracellular pathways of membrane transport.
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Bacterial Protein Toxins and cell vesicle trafficking.
Experientia, 1996Co-Authors: Cesare Montecucco, Emanuele Papini, Giampietro SchiavoAbstract:A group of bacterial Protein Toxins interfere with vesicular trafficking inside cells. Clostridial neuroToxins affect mainly the highly regulated fusion of neurotransmitter- and hormone-containing vesicles with the plasma membrane. They cleave the three SNARE Proteins: VAMP, SNAP-25 and syntaxin, and this selective proteolysis results in a blockade of exocytosis. TheHelicobacter pylori cytotoxin is implicated in the pathogenesis of gastroduodenal ulcers. It causes a progressive and extensive vacuolation of cells followed by necrosis, after a cytotoxin-induced alteration of membrane trafficking by late endosomes. Vacuoles originate from this compartment in a rab7-dependent process and swell because they are acidic and accumulate membrane-permeant amines.
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Translocation of bacterial Protein Toxins across membranes
Biochemistry of Cell Membranes, 1995Co-Authors: Cesare Montecucco, Giampietro Schiavo, Emanuele Papini, Ornella Rossetto, M. De Bernard, Fiorella Tonello, G. N. Moll, Philip WashbourneAbstract:Many bacterial Protein Toxins act inside cells by modifying a variety of cytosolic targets. To intoxicate cells, these Toxins perform a four-step process which consists of: (1) binding, (2) internalization, (3) membrane translocation, and (4) target modification. All of them form ion channels across planar lipid bilayers and plasma membrane of cells. A relation between ion channel and membrane translocation may be inferred and two different models have been put forward to account for these phenomena. The two models are discussed on the basis of the available experimental evidence and in terms of the main points of difference to be tested in future investigations.
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Cell penetration of bacterial Protein Toxins.
Trends in microbiology, 1995Co-Authors: Cesare Montecucco, Emanuele PapiniAbstract:I mportant advances have been made recently in the study of cell penetration by bacterial Protein Toxins . I,* Many Protein Toxins from bacteria and plants have their effects in the cytosol of cells. Rather than reaching their targets directly through the plasma membrane, these Toxins exploit the endocytotic pathway and enter the cytosol from intracellular compartments. As discussed recently3, the process of cell intoxication consists of four steps: (1) binding, (2) internalization, (3) membrane translocation, and (4) target modification. This elaborate mechanism of action relies on a common structural architecture. These Toxins are all made up of two main elements linked via a single disulfide bridge, A being an enzymatic subunit and B a protomer that mediates cell binding and penetration. The B portions of some Toxins, including cholera toxin, Escherichia coli heatlabile toxin, Shiga Toxins and pertussis toxin, are oligomers that bind lipidor Protein-linked sugars of the cell surface (Refs 4,5 and references therein). Another group of Toxins consists of diphtheria toxin (DT), exotoxin A of Pseudomonas aeruginosa (ETA), tetanus (TeNT) and botulism neuroToxins and the Bacillus anthracis toxic complex [protective antigen (PA), edema factor and lethal factor]. Their B portions are made up of two domains: a receptor-binding part, linked to another domain involved in membrane translocation”~“,6-8. These latter Toxins are thus threedomain Toxins. After cell binding, Protein Toxins are internalized inside vesicles and, according to their specificity, enter different pathways of intracellular membrane traffic. A large body of evidence indicates that the threedomain Toxins end up inside acidic intracellular compartments, and that the low pH is instrumental in causing the entry of the catalytic domain A into the cytosol (see Ref. 3 for references). The reports of Eriksen et al.’ and of Beise et al.’ deal with membrane translocation, the least understood of the four steps of the whole intoxication process. It has long been known that DT forms ion channels across planar lipid bilayers at low pH (Refs 9,lO) and that this property is shared by all three-domain Toxins1’-‘4. These channels are formed by the B portion, the amino-terminal domain of which plays the major role. This was the first evidence that these Toxins change conformation at low pH in such a way that the B part inserts into the lipid bilayer. Moreover, these studies introduced a very sensitive experimental system for measuring membrane penetration and translocation of Toxins. However, such an approach has two potential biases: (1) an ‘artificial’ membrane is used, and it is not clear to what extent results can be extrapolated to the in viva situation; (2) the conductance of toxin ion channels in planar lipid bilayers (a few pS) is much lower than that of a bona fide Protein-translocating pore (hundreds of pS)“. More recently, DT and PA have been found to form ion channels in living cells’x-lx; however, their electrical properties have not been studied. Now, Eriksen et al.’ and Beise et al.’ have applied the patch-clamp technique to cells exposed to DT and TeNT, and have been able to demonstrate that these Toxins do form discrete channels with con-
Kirsten Sandvig - One of the best experts on this subject based on the ideXlab platform.
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Lipid requirements for entry of Protein Toxins into cells
Progress in lipid research, 2014Co-Authors: Kirsten Sandvig, Jonas Bergan, Simona Kavaliauskiene, Tore SkotlandAbstract:The plant toxin ricin and the bacterial toxin Shiga toxin both belong to a group of Protein Toxins having one moiety that binds to the cell surface, and another, enzymatically active moiety, that enters the cytosol and inhibits Protein synthesis by inactivating ribosomes. Both Toxins travel all the way from the cell surface to endosomes, the Golgi apparatus and the ER before the ribosome-inactivating moiety enters the cytosol. Shiga toxin binds to the neutral glycosphingolipid Gb3 at the cell surface and is therefore dependent on this lipid for transport into the cells, whereas ricin binds both glycoProteins and glycolipids with terminal galactose. The different steps of transport used by these Toxins have specific requirements for lipid species, and with the recent developments in mass spectrometry analysis of lipids and microscopical and biochemical dissection of transport in cells, we are starting to see the complexity of endocytosis and intracellular transport. In this article we describe lipid requirements and the consequences of lipid changes for the entry and intoxication with ricin and Shiga toxin. These Toxins can be a threat to human health, but can also be exploited for diagnosis and therapy, and have proven valuable as tools to study intracellular transport.
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retrograde transport of Protein Toxins through the golgi apparatus
Histochemistry and Cell Biology, 2013Co-Authors: Kirsten Sandvig, Tore Skotland, Bo Van Deurs, Tove Irene KlokkAbstract:A number of Protein Toxins from plants and bacteria take advantage of transport through the Golgi apparatus to gain entry into the cytosol where they exert their action. These Toxins include the plant toxin ricin, the bacterial Shiga Toxins, and cholera toxin. Such Toxins bind to lipids or Proteins at the cell surface, and they are endocytosed both by clathrin-dependent and clathrin-independent mechanisms. Sorting to the Golgi and retrograde transport to the endoplasmic reticulum (ER) are common to these Toxins, but the exact mechanisms turn out to be toxin and cell-type dependent. In the ER, the enzymatically active part is released and then transported into the cytosol, exploiting components of the ER-associated degradation system. In this review, we will discuss transport of different Protein Toxins, but we will focus on factors involved in entry and sorting of ricin and Shiga toxin into and through the Golgi apparatus.
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Protein Toxins from plants and bacteria: probes for intracellular transport and tools in medicine.
FEBS letters, 2010Co-Authors: Kirsten Sandvig, Tore Skotland, Maria Lyngaas Torgersen, Nikolai Engedal, Tore Geir IversenAbstract:A number of Protein Toxins produced by bacteria and plants enter eukaryotic cells and inhibit Protein synthesis enzymatically. These Toxins include the plant toxin ricin and the bacterial toxin Shiga toxin, which we will focus on in this article. Although a threat to human health, Toxins are valuable tools to discover and characterize cellular processes such as endocytosis and intracellular transport. Bacterial infections associated with toxin production are a problem worldwide. Increased knowledge about Toxins is important to prevent and treat these diseases in an optimal way. Interestingly, Toxins can be used for diagnosis and treatment of cancer.
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Pathways followed by Protein Toxins into cells
International journal of medical microbiology : IJMM, 2004Co-Authors: Kirsten Sandvig, Bjørn Spilsberg, Silje Ugland Lauvrak, Maria Lyngaas Torgersen, Tore Geir Iversen, B. Van DeursAbstract:Abstract A number of Protein Toxins have an enzymatically active part, which is able to modify a cytosolic target. Some of these Toxins, for instance ricin, Shiga toxin and cholera toxin, which we will focus on in this article, exert their effect on cells by first binding to the cell surface, then they are endocytosed, and subsequently they are transported retrogradely all the way to the ER before translocation of the enzymatically active part to the cytosol. Thus, studies of these Toxins can provide information about pathways of intracellular transport. Retrograde transport to the Golgi and the ER seems to be dependent not only on different Rab and SNARE Proteins, but also on cytosolic calcium, phosphatidylinositol 3-kinase and cholesterol. Comparison of the three Toxins reveals differences indicating the presence of more than one pathway between early endosomes and the Golgi apparatus or, alternatively, that transport of different toxin-receptor complexes present in a certain subcompartment is differentially regulated.
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transport of Protein Toxins into cells pathways used by ricin cholera toxin and shiga toxin
FEBS Letters, 2002Co-Authors: Kirsten Sandvig, B. Van DeursAbstract:Ricin, cholera, and Shiga toxin belong to a family of Protein Toxins that enter the cytosol to exert their action. Since all three Toxins are routed from the cell surface through the Golgi apparatus and to the endoplasmic reticulum (ER) before translocation to the cytosol, the Toxins are used to study different endocytic pathways as well as the retrograde transport to the Golgi and the ER. The Toxins can also be used as vectors to carry other Proteins into the cells. Studies with Protein Toxins reveal that there are more pathways along the plasma membrane to ER route than originally believed.
Syed Imteyaz Alam - One of the best experts on this subject based on the ideXlab platform.
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Multiplex Detection of Protein Toxins Using MALDI-TOF-TOF Tandem Mass Spectrometry: Application in Unambiguous Toxin Detection from Bioaerosol
2016Co-Authors: Syed Imteyaz Alam, Bhoj Kumar, Dev Vrat KambojAbstract:Protein Toxins, such as botulinum neuroToxins (BoNTs), Clostridium perfringens epsilon toxin (ETX), staphylococcal enterotoxin B (SEB), shiga toxin (STX), and plant toxin ricin, are involved in a number of diseases and are considered as potential agents for bioterrorism and warfare. From a bioterrorism and warfare perspective, these agents are likely to cause maximum damage to a civilian or military population through an inhalational route of exposure and aerosol is considered the envisaged mode of delivery. Unambiguous detection of toxin from aerosol is of paramount importance, both for bringing mitigation protocols into operation and for implementation of effective medical countermeasures, in case a “biological cloud” is seen over a population. A multiplex, unambiguous, and qualitative detection of Protein Toxins is reported here using tandem mass spectrometry with MALDI-TOF-TOF. The methodology involving simple sample processing steps was demonstrated to identify Toxins (ETX, Clostridium perfringes phospholipase C, and SEB) from blind spiked samples. The novel directed search approach using a list of unique peptides was used to identify Toxins from a complex Protein mixture. The bioinformatic analysis of seven Protein Toxins for elucidation of unique peptides with conservation status across all known sequences provides a high confidence for detecting Toxins originating from any geographical location and source organism. Use of tandem MS data with peptide sequence information increases the specificity of the method. A prototype for generation of aerosol using a nebulizer and collection using a cyclone collector was used to provide a proof of concept for unambiguous detection of toxin from aerosol using precursor directed tandem mass spectrometry combined with Protein database searching. ETX prototoxin could be detected from aerosol at 0.2 ppb concentration in aerosol
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Multiplex detection of Protein Toxins using MALDI-TOF-TOF tandem mass spectrometry: application in unambiguous toxin detection from bioaerosol.
Analytical chemistry, 2012Co-Authors: Syed Imteyaz Alam, Bhoj Kumar, Dev Vrat KambojAbstract:Protein Toxins, such as botulinum neuroToxins (BoNTs), Clostridium perfringens epsilon toxin (ETX), staphylococcal enterotoxin B (SEB), shiga toxin (STX), and plant toxin ricin, are involved in a number of diseases and are considered as potential agents for bioterrorism and warfare. From a bioterrorism and warfare perspective, these agents are likely to cause maximum damage to a civilian or military population through an inhalational route of exposure and aerosol is considered the envisaged mode of delivery. Unambiguous detection of toxin from aerosol is of paramount importance, both for bringing mitigation protocols into operation and for implementation of effective medical countermeasures, in case a “biological cloud” is seen over a population. A multiplex, unambiguous, and qualitative detection of Protein Toxins is reported here using tandem mass spectrometry with MALDI-TOF-TOF. The methodology involving simple sample processing steps was demonstrated to identify Toxins (ETX, Clostridium perfringes pho...
