Search results for "Phosphorylation"
showing 10 items of 975 documents
Dephosphorylation of p-ERK1/2 in relation to tumor remission after HER-2 and Raf1 blocking therapy in a conditional mouse tumor model
2006
Several studies have shown that HER-2/neu (erbB-2) blocking therapy strategies can cause tumor remission. However, the responsible molecular mechanisms are not yet known. Both ERK1/2 and Akt/PKB are critical for HER-2-mediated signal transduction. Therefore, we used a mouse tumor model that allows downregulation of HER-2 in tumor tissue by administration of anhydrotetracycline (ATc). Switching-off HER-2 caused a rapid tumor remission by more than 95% within 7 d of ATc administration compared to the volume before switching-off HER-2. Interestingly, HER-2 downregulation caused a dephosphorylation of p-ERK1/2 by more than 80% already before tumor remission occurred. Levels of total ERK protein…
Pentoxifylline Prevents Loss of PP2A Phosphatase Activity and Recruitment of Histone Acetyltransferases to Proinflammatory Genes in Acute Pancreatitis
2009
Mitogen-activated protein kinases (MAPKs) are considered major signal transducers early during the development of acute pancreatitis. Pentoxifylline is a phosphodiesterase inhibitor with marked anti-inflammatory properties through blockade of extracellular signal regulated kinase (ERK) phosphorylation and tumor necrosis factor alpha production. Our aim was to elucidate the mechanism of action of pentoxifylline as an anti-inflammatory agent in acute pancreatitis. Necrotizing pancreatitis induced by taurocholate in rats and taurocholate-treated AR42J acinar cells were studied. Phosphorylation of ERK and ERK kinase (MEK1/2), as well as PP2A, PP2B, and PP2C serine/threonine phosphatase activiti…
Phosphorylation of extracellular signal-related protein kinase is required for rapid facilitation of heat-induced currents in rat dorsal root ganglio…
2005
A subgroup of dorsal root ganglion (DRG) neurons responds to noxious heat with an influx of cations carried by specific ion channels such as the transient receptor potential channel of the vanilloid receptor type, subtype 1 (TRPV1). Application of capsaicin induces a reversible facilitation of these currents. This facilitation could be an interaction of two agonists at their common receptor or be caused by an influx of calcium ions into the cell. Calcium influx into the cell can activate protein kinases such as the extracellular signal-related protein kinase (ERK) pathway. This study explored the kinetics, calcium-dependency and intracellular signals following application of capsaicin and l…
Inactivation of glycogen synthase kinase-3β protects against kainic acid-induced neurotoxicity in vivo
2004
Many neurodegenerative diseases involve oxidative stress and excitotoxic cell death. In an attempt to further elucidate the signal transduction pathways involved in the cell death/cell survival associated with excitotoxicity, we have used an in vivo model of excitotoxicity employing kainic acid (KA)-induced neurotoxicity. Here, we show that extracellular signal-related kinase (ERK) 2, but not ERK 1, is phosphorylated and thereby activated in the hippocampus and cerebellum of kainic acid-treated mice. Phosphorylation and hence inactivation of glycogen synthase kinase 3beta (GSK-3beta), a general survival factor, is often a downstream consequence of mitogen-activated protein kinase pathway ac…
Hormone replacement therapy enhances IGF-1 signaling in skeletal muscle by diminishing miR-182 and miR-223 expressions : a study on postmenopausal mo…
2014
MiRNAs are fine-tuning modifiers of skeletal muscle regulation, but knowledge of their hormonal control is lacking. We used a co-twin case-control study design, that is, monozygotic postmenopausal twin pairs discordant for estrogen-based hormone replacement therapy (HRT) to explore estrogen-dependent skeletal muscle regulation via miRNAs. MiRNA profiles were determined from vastus lateralis muscle of nine healthy 54-62-years-old monozygotic female twin pairs discordant for HRT (median 7 years). MCF-7 cells, human myoblast cultures and mouse muscle experiments were used to confirm estrogen's causal role on the expression of specific miRNAs, their target mRNAs and proteins and finally the act…
MUC16 Is Overexpressed in Idiopathic Pulmonary Fibrosis and Induces Fibrotic Responses Mediated by Transforming Growth Factor-β1 Canonical Pathway
2021
Several transmembrane mucins have demonstrated that they contribute intracellularly to induce fibrotic processes. The extracellular domain of MUC16 is considered as a biomarker for disease progression and death in IPF patients. However, there is no evidence regarding the signalling capabilities of MUC16 that contribute to IPF development. Here, we demonstrate that MUC16 was overexpressed in the lung tissue of IPF patients (n = 20) compared with healthy subjects (n = 17) and localised in fibroblasts and hyperplastic alveolar type II cells. Repression of MUC16 expression by siRNA-MUC16 transfection inhibited the TGF-β1-induced fibrotic processes such as mesenchymal/ myofibroblast transformati…
The basal levels of 8-oxoG and other oxidative modifications in intact mitochondrial DNA are low even in repair-deficient (Ogg1(-/-)/Csb(-/-)) mice.
2007
Abstract Mitochondrial DNA (mtDNA) is assumed to be highly prone to damage by reactive oxygen species (ROS) because of its location in close proximity to the mitochondrial electron transport chain. Accordingly, mitochondrial oxidative DNA damage has been hypothesized to be responsible for various neurological diseases, ageing and cancer. Since 7,8-dihydro-8-oxoguanine (8-oxoG), one of the most frequent oxidative base modifications, is removed from the mitochondrial genome by the glycosylase OGG1, the basal levels of this lesion are expected to be highly elevated in Ogg1−/− mice. To investigate this hypothesis, we have used a mtDNA relaxation assay in combination with various repair enzymes …
Molecular oncology focus - is carcinogenesis a 'mitochondriopathy'?
2010
Abstract Mitochondria are sub-cellular organelles that produce adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS). As suggested over 70 years ago by Otto Warburg and recently confirmed with molecular techniques, alterations in respiratory activity and in mitochondrial DNA (mtDNA) appear to be common features of malignant cells. Somatic mtDNA mutations have been reported in many types of cancer cells, and some reports document the prevalence of inherited mitochondrial DNA polymorphisms in cancer patients. Nevertheless, a careful reanalysis of methodological criteria and methodology applied in those reports has shown that numerous papers can't be used as relevant sources …
AZT induces oxidative damage to cardiac mitochondria: Protective effect of vitamins C and E
2004
Abstract AZT (zidovudine) is a potent inhibitor of HIV replication and a major antiretroviral drug used for AIDS treatment. A major limitation in the use of AZT is the occurrence of severe side effects. The aim of this work was to test whether AZT causes oxidative damage to heart mitochondria and whether this can be prevented by supranutritional doses of antioxidant vitamins. An experimental animal model was used in which mice were treated with AZT for 35 days (10 mg/kg/day) in drinking water. Animals treated with antioxidant vitamins were fed the same diet as controls but supplemented with vitamins C (ascorbic acid, 10 g/ kg diet) and E (α-dl-tocopherol, 0.6 g/kg diet) for 65 days before s…
The N-terminal domain of mammalian soluble epoxide hydrolase is a phosphatase
2003
The mammalian soluble epoxide hydrolase (sEH) is an enzyme with multiple functions, being implicated in detoxification of xenobiotic epoxides as well as in regulation of physiological processes such as blood pressure. The enzyme is a homodimer, in which each subunit is composed of two domains. The 35-kDa C-terminal domain has an α/β hydrolase fold and harbors the catalytic center for the EH activity. The 25-kDa N-terminal domain has a different α/β fold and belongs to the haloacid dehalogenase superfamily of enzymes. The catalytic properties of the enzyme reported so far can all be explained by the action of the C-terminal domain alone. The function of the N-terminal domain, other than in …