Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Menkes disease protein (ATP7A or MNK) is a P-type transmembrane ATPase that regulates translocation of cytosolic copper ions across intracellular membranes of compartments along the secretory pathway. In this study, we show that endogenous MNK in cultured cell lines is localized to the distal Golgi apparatus and translocates to the plasma membrane in response to exogenous copper ions. This transport event is not blocked by expression of a dominant-negative mutant protein kinase D, an enzyme implicated in regulating constitutive trafficking from the trans-Golgi network (TGN) to the plasma membrane, whereas constitutive transport of CD4 is inhibited. In contrast, protein kinase A inhibitors block copper-stimulated MNK delivery to the plasma membrane. Expression of constitutively active Rho GTPases such as Cdc42, Rac1 and RhoA reveals a requirement for Cdc42 in the trafficking of MNK, to the cell surface. Furthermore, overexpression of WASp inhibits anterograde transport of MNK, further supporting regulation by the Cdc42 GTPase. These findings define a novel step in TGN-to-plasma membrane traffic required to export MNK to the cell surface.
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PMID:Novel membrane traffic steps regulate the exocytosis of the Menkes disease ATPase. 1239 97

Epidemiologic studies have shown positive associations between changes in ambient particulate matter (PM) levels in Utah Valley during 1986-1988, and the respiratory health of the local population. Ambient PM reductions coincided with closure of an open-hearth steel mill, the major industrial source of particulate emissions in the valley. In this report, water extracts of PM filters from steel mill operational (UE-86, UE-88) and closure (UE-87) periods were analyzed for their elemental composition. Their relative toxicity was determined by exposing primary rodent airway epithelial cultures to equal masses of extracted material. To elucidate extract subcomponents mediating the effects observed, cells were also exposed to surrogate metal mixtures. Potential interactions between the two predominant metals in the UE-86/88 samples, zinc (Zn) and copper (Cu), were further investigated. Data indicated that, relative to the UE-87 (plant closed) sample, UE-86/88 samples contained more sulfate, calcium, potassium,magnesium and, although present in much lower amounts, a variety of metals including Zn,Cu, iron, lead, strontium, nickel, manganese, and vanadium (V). Cell exposure to UE-86 and UE-88, but not UE-87, resulted in time- and concentration-dependent epithelial injury based on biochemical and light/electron microscopic changes. Cell injury induced by metal mixtures containing equivalent amounts of Zn + Cu + V was commensurate with that induced by the corresponding extract, although divergent antioxidant responses were observed. Exposure to Zn + Cu resulted in significantly greater epithelial toxicity and stress (c-Jun N-terminal protein kinase activation) responses than did exposure to Zn or Cu individually. The parallel epithelial injury induced by the extracts and their surrogate Zn + Cu + V mixtures suggests that these metals are mediating the acute airway epithelial effects observed; however, metal interactions appear to play a critical role in the overall cellular effects induced by the PM-derived extracts. These experimental findings are in good accord with epidemiologic reports of adverse airway and respiratory health health effects in Utah Valley residents.
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PMID:Metals mimic airway epithelial injury induced by in vitro exposure to Utah Valley ambient particulate matter extracts. 1285 32

A series of naturally occurring isoquinoline alkaloids, besides their distribution in the environment and presence in certain food stuffs, have been detected in human tissues including particular regions of brain. An example is salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) that not only induces neuronal cell death, but also causes DNA damage and genotoxicity. Tetrahydropapaveroline [THP; 6,7-dihydroxy-1-(3',4'-dihydroxybenzyl)-1,2,3,4-tetrahydroisoquinoline], a dopamine-derived tetrahydroisoquinoline alkaloid, has been reported to inhibit mitochondrial respiration and is considered to contribute to neurodegeneration implicated in Parkinson's disease. Since THP bears two catechol moieties, the compound may readily undergo redox cycling to produce reactive oxygen species (ROS) as well as toxic quinoids. In the present study, we have examined the capability of THP to cause oxidative DNA damage and cell death. Incubation of THP with phiX174 supercoiled DNA or calf thymus DNA in the presence of cupric ion caused substantial DNA damage as determined by strand scission or formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), respectively. THP plus copper-induced DNA damage was ameliorated by some ROS scavengers/antioxidants and catalase. Treatment of C6 glioma cells with THP led to a concentration-dependent reduction in cell viability, which was prevented by the antioxidant N-acetyl-L-cysteine. When these cells were treated with 10microM THP, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) were rapidly activated via phosphorylation, whereas activation of extracellular signal-regulated protein kinase (ERK) was inhibited. Furthermore, pretreatment with inhibitors of JNK and p38 MAPK rescued the glioma cells from THP-induced cytotoxicity, suggestive of the involvement of these kinases in THP-induced C6 glioma cell damage.
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PMID:Oxidative DNA damage and glioma cell death induced by tetrahydropapaveroline. 1464 15

Oxidative damage to the endoplasmic reticulum (ER) could be involved in ischemic neuronal cell death because this organelle is susceptible to reactive oxygen species. Using wild-type mice and copper/zinc-superoxide dismutase (SOD1) transgenic mice, we induced focal cerebral ischemia and compared neuronal degeneration and ER stress, that is, phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha) and RNA-dependent protein kinase-like ER eIF2alpha kinase (PERK). We found that neurons with severe and prolonged phosphorylation of eIF2alpha and PERK underwent later degeneration, and that this was partially prevented by SOD1 overexpression. Signals for superoxide production and phospho-PERK were colocalized, which further indicates a pivotal role for superoxide in ER damage. We investigated the molecular mechanisms of oxidative ER stress and found that detachment of glucose-regulated protein 78 from PERK was the key step. We conclude that ER damage is involved in oxidative neuronal injury in the brain after ischemia/reperfusion.
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PMID:Oxidative injury to the endoplasmic reticulum in mouse brains after transient focal ischemia. 1500 93

Neurofibrillary tangles (NFT) containing paired helical filaments (PHF) composed of abnormally phosphorylated tau are one of the hallmark lesions of the Alzheimer's disease (AD) brain. Although phosphorylation of tau is thought to precede the formation of PHF, the kinases/phosphatases involved remain poorly understood. Here we report that treatment of primary rat cortical neuron cultures with cuprizone, a copper chelator, in combination with oxidative stress (Fe(2+)/H(2)O(2)), significantly increased aberrant tau phosphorylation identified by TG3 immunochemistry. To determine the potential contribution of glycogen synthase kinase-3 (GSK-3) to the phosphorylation of tau in this model, activity of GSK-3 was determined. Cultures treated with cuprizone/Fe(2+)/H(2)O(2) showed significantly increased GSK-3 activity compared with control cultures or cultures treated with cuprizone, or Fe(2+)/H(2)O(2) alone. Concomitant treatment of cultures with lithium, a GSK-3 inhibitor, significantly decreased GSK-3 activity and reduced TG3 staining. Together these data suggest a culture model of hyperphosphorylated tau that implicates increased GSK-3 activity.
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PMID:Induction of hyperphosphorylated tau in primary rat cortical neuron cultures mediated by oxidative stress and glycogen synthase kinase-3. 1566 6

The cellular prion protein (PrP(C)) is thought to be involved in protection against cell death, however the exact cellular mechanisms involved are still controversial. Herein we present data that strongly indicate a functional link between PrP(C) expression and phosphatidylinositol 3-kinase (PI 3-kinase) activation, a protein kinase that plays a pivotal role in cell survival. Both mouse neuroblastoma N2a cells and immortalized murine hippocampal neuronal cell lines expressing wild-type PrP(C) had significantly higher PI 3-kinase activity levels than their respective controls. Moreover, PI 3-kinase activity was found to be elevated in brain lysates from wild-type mice, as compared to prion protein-knockout mice. Recruitment of PI 3-kinase by PrP(C) was shown to contribute to cellular survival toward oxidative stress by using 3-morpholinosydnonimine (SIN-1) and serum deprivation. Moreover, both PI 3-kinase activation and cytoprotection by PrP(C) appeared to rely on copper binding to the N-terminal octapeptide of PrP(C). Thus, we propose a model in which the interaction of copper(II) with the N-terminal domain of PrP(C) enables transduction of a signal to PI 3-kinase; the latter, in turn, mediates downstream regulation of cell survival.
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PMID:Activation of phosphatidylinositol 3-kinase by cellular prion protein and its role in cell survival. 1589 1

We have characterized comprehensive transcript and proteomic profiles of cell lines corresponding to normal breast (MCF10A), noninvasive breast cancer (MCF7) and invasive breast cancer (MDA-MB-231). The transcript profiles were first analysed by a modified protocol for representational difference analysis (RDA) of cDNAs between MCF7 and MDA-MB-231 cells. The majority of genes identified by RDA showed nearly complete concordance with microarray results, and also led to the identification of some differentially expressed genes such as lysyl oxidase, copper transporter ATP7A, EphB6, RUNX2 and a variant of RUNX2. The altered transcripts identified by microarray analysis were involved in cell-cell or cell-matrix interaction, Rho signaling, calcium homeostasis and copper-binding/sensitive activities. A set of nine genes that included GPCR11, cadherin 11, annexin A1, vimentin, lactate dehydrogenase B (upregulated in MDA-MB-231) and GREB1, S100A8, amyloid beta precursor protein, claudin 3 and cadherin 1 (downregulated in MDA-MB-231) were sufficient to distinguish MDA-MB-231 from MCF7 cells. The downregulation of a set of transcripts for proteins involved in cell-cell interaction indicated these transcripts as potential markers for invasiveness that can be detected by methylation-specific PCR. The proteomic profiles indicated altered abundance of fewer proteins as compared to transcript profiles. Antisense knockdown of selected transcripts led to inhibition of cell proliferation that was accompanied by altered proteomic profiles. The proteomic profiles of antisense transfectants suggest the involvement of peptidyl-prolyl isomerase, Raf kinase inhibitor and 80 kDa protein kinase C substrate in mediating the inhibition of cell proliferation.
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PMID:Gene expression signatures and biomarkers of noninvasive and invasive breast cancer cells: comprehensive profiles by representational difference analysis, microarrays and proteomics. 1631 37

Molecular mechanisms of morphogenesis share many common components between Candida albicans and Saccharomyces cerevisiae. The Kss1-associated MAPK cascade and the cAMP/PKA pathway are two important signal transduction pathways that control morphogenesis in S. cerevisiae. A C. albicans copper ion-sensing transcription factor gene, CaMAC1, was cloned from C. albicans SC5314. Ectopic expression of CaMAC1 in S. cerevisiae promoted filamentous and invasive growth. In diploid cells, CaMac1 could suppress the filamentous growth defect of mutants in the Kss1-associated MAPK pathway and the cAMP/PKA pathway. In haploid strains, ectopic expression of CaMAC1 suppressed the invasive growth defect of mutants in the MAPK pathway (ste7, ste12 and tec1), but failed to suppress the invasive growth defect of the flo8 mutant. Our results suggest that the activation of CaMac1 is independent of the MAPK and cAMP/PKA pathways in filament formation, but requires Flo8 factor for invasive growth. In the media containing a high concentration of CuSO4, the yeast filamentous and invasive growth was blocked. The activating effect of CaMac1 is inhibited by copper ions.
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PMID:CaMac1, a Candida albicans copper ion-sensing transcription factor, promotes filamentous and invasive growth in Saccharomyces cerevisiae. 1651 47

Cells respond to heavy metal stress by activating signaling cascades regulating cellular proliferation and survival. We here demonstrate that the anti-apoptotic kinase Akt is activated in HepG2 human hepatoma cells exposed to copper or zinc ions. Cu2+- and Zn2+-induced phosphorylation of Akt was blocked by phosphoinositide 3-kinase (PI3K) inhibitors, wortmannin and LY294002. Moreover, several endogenous Akt substrates were phosphorylated, including glycogen synthase kinase-3 and transcription factors of the FoxO family, FoxO1a and FoxO4. Exposure to Cu2+ or Zn2+ elicited the subcellular redistribution of an overexpressed FoxO1a-EGFP fusion protein from nucleus to cytoplasm, which was not seen with a mutant FoxO1a form devoid of Akt phosphorylation sites. Both FoxO phosphorylation and nuclear exclusion were blocked by wortmannin. Likewise, the subcellular translocation from nucleus to cytoplasm of the Caenorhabditis elegans FoxO ortholog, DAF-16, was caused in starved worms exposed to copper ions. Activity of the promoter of the human glucose 6-phosphatase gene, known to be regulated by insulin and FoxO1a, was demonstrated in reporter gene assays to be attenuated in hepatoma cells exposed to Cu2+. However, this suppression of glucose 6-phosphatase promoter activity was independent of modulation of the PI3K/Akt pathway. In summary, the PI3K/Akt pathway is activated in human hepatoma cells exposed to Cu2+ or Zn2+, resulting in the phosphorylation and subcellular relocalisation of transcription factor FoxO1a. Furthermore, copper is demonstrated to exert an insulin-mimetic effect also independently of the PI3K/Akt/FoxO pathway.
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PMID:Modulation of FoxO signaling in human hepatoma cells by exposure to copper or zinc ions. 1697 22

Excessive copper concentrations, known to induce reactive oxygen species (ROS) formation, have been tested with respect to their effects on transcript abundance and related proteins involved in oxidative stress responses. The results show that the stromal photosynthetic functions were more ROS sensitive than the membrane-located reactions. The rbcL over-expression compensated for the damage only at 10 microM Cu, whereas the genetic stimulation of alpha-tocopherol biosynthesis led to the protection of membrane reactions up to 50-100 microM Cu. For this reason, the gradual growth drop of Chlamydomonas reinhardtii cultures observed under increasing Cu(2+) concentrations matched better with the loss of photosynthetic capacity than with those of photosynthetic quantum yields. According to Larcher's stress concept, the results allow the identification of gene markers for the alarm (rbcL), the hardening (FeSOD, VTE3) and the exhaustion [cyclin-dependent protein kinase (cdk), psbA] phases. These genes can be used to rapidly evaluate the state of oxidative stress in algae and putatively in other plant cells.
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PMID:Parallel analysis of transcript levels and physiological key parameters allows the identification of stress phase gene markers in Chlamydomonas reinhardtii under copper excess. 1708 Dec 40


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