Search results for "Clostridium Difficile"

showing 10 items of 65 documents

Control of cellular phosphatidylinositol 4,5-bisphosphate levels by adhesion signals and Rho GTPases in NIH 3T3 fibroblasts

2000

The involvement of small GTPases of the Rho family in the control of phosphoinositide metabolism by adhesion signals was examined in NIH 3T3 fibroblasts. Abrogation of adhesion signals by detachment of cells from their substratum resulted in a time-dependent decrease in the cellular level of PtdIns(4,5)P2 by approximately 50%. This effect could be mimicked by treatment of adherent cells with Clostridium difficile toxin B and toxin B-1470, which inhibit specific subsets of Rho and Ras GTPases. Detachment of cells that had been pretreated with the clostridial toxins did not cause a further reduction in PtdIns(4,5)P2 levels, suggesting that the target GTPases are integrated into the control of…

Phosphatidylinositol 45-Diphosphaterac1 GTP-Binding Proteinrho GTP-Binding ProteinsBacterial ToxinsCellClostridium difficile toxin BRAC1GTPasePhospholipaseBiologyTransfectionBiochemistryMicechemistry.chemical_compoundPhosphoinositide Phospholipase CBacterial ProteinsCell AdhesionmedicineAnimalsPhosphorylationInositol phosphatechemistry.chemical_classificationPhospholipase CCytotoxinsPhosphoric Diester Hydrolases3T3 CellsMolecular biologyRecombinant ProteinsCell biologyKineticsPhosphotransferases (Alcohol Group Acceptor)medicine.anatomical_structurechemistryPhosphatidylinositol 45-bisphosphateType C PhospholipasesCalciumSignal TransductionEuropean Journal of Biochemistry
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Inhibition of Receptor Signaling to Phospholipase D by Clostridium difficile Toxin B

1996

Rho proteins have been reported to activate phospholipase D (PLD) in in vitro preparations. To examine the role of Rho proteins in receptor signaling to PLD, we studied the effect of Clostridium difficile toxin B, which glucosylates Rho proteins, on the regulation of PLD activity in human embryonic kidney (HEK) cells stably expressing the m3 muscarinic acetylcholine receptor (mAChR). Toxin B treatment of HEK cells potently and efficiently blocked mAChR-stimulated PLD. In contrast, basal and phorbol ester-stimulated PLD activities were not or only slightly reduced. Cytochalasin B and Clostridium botulinum C2 toxin, mimicking the effect of toxin B on the actin cytoskeleton but without involvi…

Phospholipase DG proteinClostridium difficile toxin AClostridium difficile toxin BCell BiologyBiologymedicine.disease_causeActin cytoskeletonBiochemistryMolecular biologyenzymes and coenzymes (carbohydrates)chemistry.chemical_compoundchemistrymedicineClostridium botulinumlipids (amino acids peptides and proteins)Signal transductionMolecular BiologyCytochalasin BJournal of Biological Chemistry
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Specific Inhibition of Phorbol Ester-stimulated Phospholipase D by Clostridium sordellii Lethal Toxin and Clostridium difficile Toxin B-1470 in HEK-2…

1998

Activation of m3 muscarinic acetylcholine receptor (mAChR), stably expressed in human embryonic kidney (HEK)-293 cells, leads to phospholipase D (PLD) stimulation, a process apparently involving Rho GTPases, as shown by studies with Clostridium botulinum C3 exoenzyme and Clostridium difficile toxin B (TcdB). Direct activation of protein kinase C (PKC) by phorbol esters, such as phorbol 12-myristate 13-acetate (PMA), also induces PLD stimulation, which is additive to the mAChR action and which is only poorly sensitive to inactivation of Rho proteins by TcdB. To study whether Ras-like GTPases are involved in PLD regulation, we studied the effects of the TcdB variant TcdB-1470 and Clostridium …

RALBG proteinPhospholipase DRAC1Clostridium difficile toxin BCell BiologyBiologyBiochemistryMolecular biologyRALAenzymes and coenzymes (carbohydrates)chemistry.chemical_compoundchemistryPhorbollipids (amino acids peptides and proteins)Molecular BiologyProtein kinase CJournal of Biological Chemistry
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The Enterotoxin from Clostridium difficile (ToxA) Monoglucosylates the Rho Proteins

1995

The enterotoxin from Clostridium difficile (ToxA) is one of the causative agents of the antibiotic-associated pseudomembranous colitis. In cultured monolayer cells ToxA exhibits cytotoxic activity to induce disassembly of the actin cytoskeleton, which is accompanied by morphological changes. ToxA-induced depolymerization of actin filaments is correlated with a decrease in the ADP-ribosylation of the low molecular mass GTP-binding Rho proteins (Just, I., Selzer, J., von Eichel-Streiber, C., and Aktories, K. (1995) J. Clin. Invest. 95, 1026-1031). Here we report on the identification of the ToxA-induced modification of Rho. Applying electrospray mass spectrometry, the mass of the modification…

RHOAGlycoside HydrolasesBacterial ToxinsClostridium difficile toxin ARAC1macromolecular substancesEnterotoxinBiochemistrySubstrate SpecificityEnterotoxinsGTP-Binding ProteinsTumor Cells CulturedAmino AcidsMolecular BiologyActinbiologyMolecular massClostridioides difficileCell BiologyPseudomembranous colitisActin cytoskeletonMolecular biologycarbohydrates (lipids)GlucoseBiochemistrybiology.proteinrhoA GTP-Binding ProteinJournal of Biological Chemistry
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Rho prevents apoptosis through Bcl-2 expression: Implications for interleukin-2 receptor signal transduction

1997

Here we describe a Rho-mediated apoptosis suppression pathway driven by Bcl-2 expression in the interleukin (IL)-4- or IL-2-dependent murine T cell line TS1 alpha beta. IL-2, but not IL-4, induces Bcl-2 expression through RhoA activation which is inhibited by the specific Rho family inhibitor, Clostridium difficile Toxin B, as well as by a dominant negative RhoA mutant. Using transient transfections of RhoA mutants tagged with the vesicular stomatitis virus glycoprotein, we show that a constitutively active RhoA mutant induces Bcl-2 expression and prevents apoptosis upon IL-4 withdrawal. Finally, we have identified the signaling pathway involved together with RhoA in Bcl-2 induction and sho…

RHOAImmunologyDown-RegulationClostridium difficile toxin AApoptosisClostridium difficile toxin BTransfectionCell LineMicePhosphatidylinositol 3-Kinaseschemistry.chemical_compoundGTP-Binding ProteinsAnimalsHumansImmunology and AllergyPhosphatidylinositolProtein kinase AProtein Kinase CbiologyKinaseInterleukinReceptors Interleukin-2Molecular biologyCell biologyProto-Oncogene Proteins c-bcl-2chemistrybiology.proteinInterleukin-2Signal transductionrhoA GTP-Binding ProteinSignal TransductionEuropean Journal of Immunology
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Clostridium difficile toxin A induces expression of the stress-induced early gene product RhoB.

2004

Clostridium difficile toxin A monoglucosylates the Rho family GTPases Rho, Rac, and Cdc42. Glucosylation leads to the functional inactivation of Rho GTPases and causes disruption of the actin cytoskeleton. A cDNA microarray revealed the immediate early gene rhoB as the gene that was predominantly up-regulated in colonic CaCo-2 cells after treatment with toxin A. This toxin A effect was also detectable in epithelial cells such as HT29 and Madin-Darby canine kidney cells, as well as NIH 3T3 fibroblasts. The expression of RhoB was time-dependent and correlated with the morphological changes of cells. The up-regulation of RhoB was approximately 15-fold and was based on the de novo synthesis of …

RHOAPyridinesRHOBBacterial ToxinsClostridium difficile toxin ARAC1GTPaseBiochemistryp38 Mitogen-Activated Protein KinasesGene Expression Regulation EnzymologicGene productEnterotoxinsStress PhysiologicalRhoB GTP-Binding ProteinHumansrhoB GTP-Binding ProteinMolecular BiologyOligonucleotide Array Sequence AnalysisbiologyImidazolesCell BiologyRhoBClostridium difficileActin cytoskeletonMolecular biologyUp-Regulationbiology.proteinGene expressionCaco-2 CellsThe Journal of biological chemistry
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Rho protein-mediated changes in the structure of the actin cytoskeleton regulate human inducible NO synthase gene expression ☆ ☆This article contains…

2003

Rho proteins (Rho, Rac, Cdc 42) are known to control the organization of the actin cytoskeleton as well as gene expression. Inhibition of Rho proteins by Clostridium difficile toxin B disrupted the F-actin cytoskeleton and enhanced cytokine-induced inducible nitric oxide synthase (iNOS) expression in human epithelial cells. Also specific inhibition by Y-27632 of p160ROCK, which mediates Rho effects on actin fibers, caused a disruption of the actin cytoskeleton and a superinduction of cytokine-induced iNOS expression. Accordingly, direct disruption of the actin cytoskeleton by cytochalasin D, latrunculin B, or jasplakinolide enhanced cytokine-induced iNOS expression. The transcription factor…

Regulation of gene expressionActin remodelingClostridium difficile toxin Bmacromolecular substancesCell BiologyBiologyActin cytoskeletonMolecular biologyCell biologyProfilinSerum response factorbiology.proteinMDia1CytoskeletonExperimental Cell Research
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Inhibition of FcεRI-mediated Activation of Rat Basophilic Leukemia Cells by Clostridium difficile Toxin B (Monoglucosyltransferase)

1996

Abstract Treatment of rat basophilic leukemia (RBL) 2H3-hm1 cells with Clostridium difficile toxin B (2 ng/ml), which reportedly depolymerizes the actin cytoskeleton, blocked [3H]serotonin release induced by 2,4-dinitrophenyl-bovine serum albumin, carbachol, mastoparan, and reduced ionophore A23187-stimulated degranulation by about 55-60%. In lysates of RBL cells, toxin B 14C-glucosylated two major and one minor protein. By using two-dimensional gel electrophoresis and immunoblotting, RhoA and Cdc42 were identified as protein substrates of toxin B. In contrast to toxin B, Clostridium botulinum transferase C3 that selectively inactivates RhoA by ADP-ribosylation did not inhibit degranulation…

SerotoninRHOABacterial ToxinsClostridium difficile toxin AWasp VenomsClostridium difficile toxin BBiologyCytoplasmic GranulesTritiummedicine.disease_causeBiochemistryCell LinePhosphatidylinositol 3-KinasesBacterial ProteinsTumor Cells CulturedmedicineAnimalsEnzyme InhibitorsMolecular BiologyCalcimycinAdenosine Diphosphate RiboseClostridioides difficileReceptors IgEToxinDegranulationSerum Albumin BovineCell BiologyActin cytoskeletonMolecular biologyRatsAndrostadienesKineticsPhosphotransferases (Alcohol Group Acceptor)Leukemia Basophilic AcuteBiochemistryGlucosyltransferasesMastoparanbiology.proteinIntercellular Signaling Peptides and ProteinsClostridium botulinumCarbacholCattle24-DinitrophenolPeptidesWortmanninDinitrophenolsJournal of Biological Chemistry
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Closing in on the toxic domain through analysis of a variant Clostridium difficile cytotoxin B

1995

Strain 1470 is the standard typing strain for serogroup F of Clostridium difficile containing both toxin genes, toxA-1470 and toxB-1470. A polymerase chain reaction (PCR)-based approach to the sequencing of the total toxB-1470 gene identified an open reading frame (ORF) of 7104 nucleotides. In comparison with the previously sequenced toxB of C. difficile VP10463, the toxB-1470 gene has 16 additional nucleotides, 13 within the 5'-untranslated region and three within the coding region. The M(r) of ToxB-1470 is 269,262, with an isoelectric point (IP) of 4.16. The equivalent values for ToxB are M(r) 269,709 and IP 4.13. In comparison with ToxB, ToxB-1470 differs primarily in the N-terminal regi…

SwineSequence analysisBacterial ToxinsMolecular Sequence DataRestriction MappingClostridium sordelliiMicrobiologyCell LineMicrobiologyOpen Reading FramesBacterial ProteinsAnimalsCoding regionAmino Acid SequenceCloning MolecularMolecular BiologyPeptide sequenceGeneClostridiumBase SequencebiologyClostridioides difficileCytotoxinsSequence Analysis DNAClostridium difficileClostridium novyibiology.organism_classificationActinsOpen reading frameGenes BacterialEndothelium VascularMolecular Microbiology
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Glucosylation of Rho proteins by Clostridium difficile toxin B.

1995

TOXIN A and B, the major virulence factors of Clostridium difficile, are the causative agents of antibiotic-associated pseudomembran-ous colitis. In cultured cell lines their potent cytotoxicity results from their ability to induce disaggregation of the microfilament cytoskeleton1,2. Toxin B acts on the low-molecular-mass GTPase Rho A3,4, which is involved in the regulation of the actin cytoskeleton. We report here that toxin B catalyses the incorporation of up to one mole of glucose per mole of RhoA at the amino acid thre-onine at position 37. The modification was identified and localized by tandem electrospray mass spectrometry. UDP-glucose selectively serves as cosubstrate for the monogl…

ThreonineRHOAGlycosylationBacterial ToxinsMolecular Sequence DataClostridium difficile toxin AClostridium difficile toxin Bmacromolecular substancesmedicine.disease_causeMicrofilamentCatalysisMass SpectrometryGTP PhosphohydrolasesBacterial ProteinsGTP-Binding ProteinsmedicineTumor Cells CulturedAnimalsAmino Acid SequenceCytoskeletonActinCells CulturedCytoskeletonMultidisciplinarybiologyToxinClostridioides difficileActin cytoskeletonActinsRecombinant ProteinsRatsGlucoseMarsupialiaBiochemistryGlucosyltransferasesbiology.proteinrhoA GTP-Binding ProteinNature
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