Search results for "Transferase"
showing 10 items of 1030 documents
Talin1 sets the stage for dendritic cell activation
2020
In dendritic cells, talin1 links integrin binding to efficient TLR downstream signaling through interaction with MyD88 and PIP5K.
Epigenetic Regulation of Early- and Late-Response Genes in Acute Pancreatitis
2015
Abstract Chromatin remodeling seems to regulate the patterns of proinflammatory genes. Our aim was to provide new insights into the epigenetic mechanisms that control transcriptional activation of early- and late-response genes in initiation and development of severe acute pancreatitis as a model of acute inflammation. Chromatin changes were studied by chromatin immunoprecipitation analysis, nucleosome positioning, and determination of histone modifications in promoters of proinflammatory genes in vivo in the course of taurocholate-induced necrotizing pancreatitis in rats and in vitro in rat pancreatic AR42J acinar cells stimulated with taurocholate or TNF-α. Here we show that the upregulat…
Chromatin modifiers and recombination factors promote a telomere fold-back structure, that is lost during replicative senescence.
2020
Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance in S. cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a dis…
The role of polymorphisms of thiopurine methyltransferase in therapy with Azathioprine: preliminary study
2018
Azathioprine is an immunosuppressant drug belonging to the class of thiopurines widely used in clinical therapy. Its immunosuppressive action is linked to the substantial action mechanism in the inhibition of the synthesis of nitrogenous bases purine carried out in T-lymphocyte. The level of such medication limit resides in side effects such as myelosuppression and the development of tumours. The occurrence of side effects is linked to the presence of genetic polymorphisms of Thiopurine methyltransferase (TPMT). To date, 40 allelic variants for TPMT have been detected. However, those responsible for the reduction of enzyme activity are three: *2, *3A, *3C. The presence of one of the three p…
Thiosulfate Reduction in Salmonella enterica Is Driven by the Proton Motive Force
2012
ABSTRACT Thiosulfate respiration in Salmonella enterica serovar Typhimurium is catalyzed by the membrane-bound enzyme thiosulfate reductase. Experiments with quinone biosynthesis mutants show that menaquinol is the sole electron donor to thiosulfate reductase. However, the reduction of thiosulfate by menaquinol is highly endergonic under standard conditions (Δ E °′ = −328 mV). Thiosulfate reductase activity was found to depend on the proton motive force (PMF) across the cytoplasmic membrane. A structural model for thiosulfate reductase suggests that the PMF drives endergonic electron flow within the enzyme by a reverse loop mechanism. Thiosulfate reductase was able to catalyze the combined …
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…
Ras, Rap, and Rac Small GTP-binding Proteins Are Targets for Clostridium sordellii Lethal Toxin Glucosylation
1996
Lethal toxin (LT) from Clostridium sordellii is one of the high molecular mass clostridial cytotoxins. On cultured cells, it causes a rounding of cell bodies and a disruption of actin stress fibers. We demonstrate that LT is a glucosyltransferase that uses UDP-Glc as a cofactor to covalently modify 21-kDa proteins both in vitro and in vivo. LT glucosylates Ras, Rap, and Rac. In Ras, threonine at position 35 was identified as the target amino acid glucosylated by LT. Other related members of the Ras GTPase superfamily, including RhoA, Cdc42, and Rab6, were not modified by LT. Incubation of serum-starved Swiss 3T3 cells with LT prevents the epidermal growth factor-induced phosphorylation of m…
Oxidative DNA damage and disturbance of antioxidant capacity by alternariol in Caco-2 cells
2015
Oxidative stress occurs as a consequence of an imbalance between the prooxidant/antioxidant systems, causing an increase of intracellular generation of reactive oxygen species. Alternariol (AOH), a mycotoxin produced by Alternaria sp. can alter the action of glutathione (GSH) and the enzymes involved in the redox system, causing damage to cellular macromolecules such as DNA. The aims of this work were to determine the induction of oxidative stress by the antioxidant defenses imbalance in relation to glutathione (GSH), glutathione reductase (GR), glutathione transferase (GST), glutathione peroxidase (GPx) levels and DNA damage in Caco-2 cells derived from adenocarcinoma human colon. Oxidativ…
Expression and possible functions of the cholinergic system in a murine embryonic stem cell line.
2007
The expression of a cholinergic system during embryonic development is a widespread phenomenon. However, no precise function could be assigned to it during early pre-neural stages and there are only few studies that document when it precisely starts to be expressed. Here, we examined the expression of cholinergic components in a murine embryonic stem cell line by RT-PCR, histochemistry, and enzyme activity measurements; the acetylcholine (ACh) content was measured by HPLC. We have demonstrated that embryonic stem cells express ACh, acetylcholine receptors, choline acetyltransferase (ChAT), acetyl- and butyryl-cholinesterase (AChE and BChE). Butyryl-cholinesterase (BChE) expression was highe…
Inhibition of giant cell formation by compound 48/80 after infection with herpesvirus hominis
1974
Choline kinase has been found to be a soluble enzyme with a molecular weight of 105,000 in the cytoplasm of primary rabbit kidney cells. It has been purified 150-fold. It was investigated whether the inhibiting effect of Cpd 48/80 on virus-induced giant cell formation is due to interference with this enzyme. Cpd 48/80-dimer was shown to inhibit the choline kinase activityin vitro without a concomitant inhibition of giant cell formation. Likewise, another competitive inhibitor of choline kinase, purinyl-6-histamine, does not prevent giant cell formation. This finding suggests that there is no correlation between choline kinase activity and giant cell formation.