Search results for " phosphorylation"

In BCR-ABL-positive cells, STAT-5 tyrosine-phosphorylation integrates signals induced by imatinib mesylate and Ara-C.

2003

In BCR-ABL-positive cells, the transcription factor STAT-5 is constitutively activated by tyrosine phosphorylation. STAT-5 activation results in upregulation of bcl-X(L) and increased resistance to induction of apoptosis. Here, we investigated the effects of imatinib mesylate and cytosine arabinoside (Ara-C) on STAT-5 tyrosine-phosphorylation, cellular proliferation and induction of apoptosis in cell lines and primary hematopoietic cells. Imatinib mesylate treatment strongly suppressed STAT-5 tyrosine-phosphorylation in K562 and primary CML blasts. In contrast to JAK-2 and PI-3-kinase inhibition, exposure of K562 cells to imatinib mesylate resulted in obvious suppression of proliferation. R…

Steady-state (background) levels of oxidative DNA modifications in mammalian cells

1995

Structural Characterization of Isomeric Dimers from the Oxidative Oligomerization of Catechol with a Biomimetic Catalyst

2007

In a previous paper, it has been reported about the formation of catechol di-, tri- and tetramers within an oxidative polymerization catalyzed by synthetic water-soluble iron-porphyrin as an efficient alternative to bio-labile natural peroxidase. It has also been demonstrated the occurrence of both C-C and C-O-C coupling mechanisms. However, since the coupling products were determined by mass spectroscopy, the exact bonding position could not have been precisely ascertained for the C-C bonded isomeric dimers that are the dominant products of catechol oligomerization. Therefore, here isolation and characterization of catechol isomeric dimers, obtained by oxidative coupling under the catalysi…

Asymmetric Oxidative Mannich Reactions

2020

The asymmetric Mannich reaction is one of the most straightforward methodologies for the enantioselective synthesis of chiral amines. In general, asymmetric Mannich reactions involve the use of imines as electrophiles. However, in recent years, several asymmetric oxidative Mannich reactions have been reported using amines as electrophiles. This review provides an overview of these recent publications, including the different oxidants used and the scope and limitations of the different catalytic systems.

The role of signal transducers and activators of transcription in T inflammatory bowel diseases.

2003

Signal transducers and activators of transcription (STAT) proteins are intracellular effector molecules of cytokine-modulated signaling. On the one hand, they play an important role in hematopoiesis and the development of the human immune system. STAT transcription factors are necessary for embryogenesis and the maintenance of the mammalian immune response. In the adult, STAT signaling is responsible for T-cell polarization toward interferon gamma-secreting Th1 T cells or interleukin 4-producing Th2 cells. On the other hand, these proteins are involved in the regulation of T-cell survival. STAT activation is strongly associated with tyrosine phosphorylation by tyrosine kinases, namely Jak1,…

Oxidative stress resistance in hippocampal cells is associated with altered membrane fluidity and enhanced nonamyloidogenic cleavage of endogenous am…

2010

Reactive oxygen species (ROS) have important roles as signaling molecules in the regulation of a variety of biological processes. On the other hand, chronic oxidative stress exerted by ROS is widely considered a causative factor in aging. Therefore, cells need to be able to adapt to a chronic oxidative challenge and do so to a certain cell-type-specific extent. Recently, we have shown in oxidative-stress-resistant cell lines, HT22(H2O2) and HT22(Glu), derived from the neuronal cell line HT22 by chronic exposure to sublethal concentrations of H(2)O(2) and glutamate, that, in addition to the known antioxidant defense mechanisms, e.g., activation of antioxidant enzymes or up-regulation of heat…

Changes in carnitine octanoyltransferase activity induce alteration in fatty acid metabolism

2011

The peroxisomal beta oxidation of very long chain fatty acids (VLCFA) leads to the formation of medium chain acyl-CoAs such as octanoyl-CoA. Today, it seems clear that the exit of shortened fatty acids produced by the peroxisomal beta oxidation requires their conversion into acyl-carnitine and the presence of the carnitine octanoyltransferase (CROT). Here, we describe the consequences of an overexpression and a knock down of the CROT gene in terms of mitochondrial and peroxisomal fatty acids metabolism in a model of hepatic cells. Our experiments showed that an increase in CROT activity induced a decrease in MCFA and VLCFA levels in the cell. These changes are accompanied by an increase in …

Effect of changes in the cellular energy state on glucose transport activity in Brevibacterium flavum

2000

Abstract The effect of changes in cellular energy state on 6[14C]glucose uptake and activity of the phosphoenolpyruvate:glucose phosphotransferase system (PTS) in Brevibacterium flavum RC 115 cells was investigated. Energy generation in cells was varied by adding an inhibitor of cellular respiration (potassium cyanide) and an uncoupler of oxidative phosphorylation (pentachlorophenol) to the cell culture as well as by changing thiamine concentration in the bacterial growth medium. The results showed that glucose uptake in ‘respiring’ cells was inversely correlated with bacterial respiration activity: uptake declined with excess ATP generation and increased with lower ATP synthesis caused by …

A single bout of endurance exercise induces αB-crystallin (CRYAB) modulation in cardiac muscle as it happens in oxidative skeletal muscle fibers

2018

CRYAB is a small Heat Shock Protein, expressed in various tissues such as skeletal and cardiac muscles, activated as phosphorylated CRYAB (pCRYAB) and involved in several pathophysiological processes. In mammals there are no reports to date on CRYAB activation following an acute endurance exercise, so the aim of my study was to explore in mouse cardiac tissue the pCRYAB levels as effect of this exercise at 0’, 15’ and 120’ of recovery. H2O2 - treated HL-1 cardiomyocytes have been utilized as in vitro model to identify the underlying molecular mechanism/s. Both in vivo and in vitro models showed no changes in CRYAB protein expression level but its phosphorylation state was significantly incr…

Oxidative dehydrogenation of isobutane over Co-MCM-41 catalysts

2004

Abstract Cobalt-containing mesoporous silicates with MCM-41-like structure, with Si/Co≥49, are active and selective catalysts for the oxidative dehydrogenation (ODH) of isobutane. The formation of dehydrogenation products is analysed in terms of the nature of the cobalt species, tetrahedral Co(II), and heterogeneously initiated gas-phase reactions inside the mesopores.