Search results for "Phosphorylation"
showing 10 items of 975 documents
Activation of Cardiac c-Jun NH 2 -Terminal Kinases and p38-Mitogen–Activated Protein Kinases With Abrupt Changes in Hemodynamic Load
2001
Abstract —The role of mitogen-activated protein kinase (MAPK) pathways as signal transduction intermediates of hemodynamic stress leading to cardiac hypertrophy in the adult heart is not fully established. In a rat model of pressure-overload hypertrophy, we examined whether activation of MAPK pathways, namely, the extracellular signal–regulated protein kinase (ERK), c-Jun NH 2 -terminal kinase (JNK), and the p38-MAPK pathways, occurs during rapid changes in hemodynamic load in vivo. A slight activation of ERK2 and marked increases in JNK1 and p38-MAPK activities were observed 30 minutes after aortic banding. The increase in p38-MAPK activity was accompanied by an increase in the phosphoryl…
Molecular signaling in muscle is affected by the specificity of resistance exercise protocol
2010
Mammalian target of rapamycin and mitogen-activated protein kinase (MAPK) signaling pathways have been highlighted as important for muscle adaptations and thus, they may distinguish adaptations to different exercises. Typically, resistance exercise designed for muscle hypertrophy has moderate intensity (60-80% of one repetition maximum, 1 RM) while one prioritizing maximal strength with minor hypertrophy has a higher intensity (≥90% of 1 RM). Eight untrained men (28.4 ± 3.7 years) conducted two different bilateral leg press exercise protocols: hypertrophic (5 × 10 RM) and pure maximal strength (15 × 1 RM) in a counterbalanced, cross-over design with 1 week between exercises. Vastus laterali…
P38 MAP Kinase Signaling Is Required for the Conversion of CD4+CD25− T Cells into iTreg
2008
CD4+CD25+ regulatory T cells (Treg) are important mediators of immune tolerance. A subset of Treg can be generated in the periphery by TGF-beta dependent conversion of conventional CD4+CD25− T cells into induced Treg (iTreg). In chronic viral infection or malignancy, such induced iTreg, which limit the depletion of aberrant or infected cells, may be of pathogenic relevance. To identify potential targets for therapeutic intervention, we investigated the TGF-beta signaling in Treg. In contrast to conventional CD4+ T cells, Treg exhibited marked activation of the p38 MAP kinase pathway. Inhibition of p38 MAP kinase activity prevented the TGF-beta-dependent conversion of CD4+CD25− T cells into …
Evolution of osmosensing signal transduction in Metazoa: stress-activated protein kinases p38 and JNK.
2001
Sponges (Porifera) represent the most basal branch of the Metazoa alive today. We show that two central stress-activated protein kinases involved in the osmosensing pathway, p38 mitogen-activated protein kinase (MAPK) and JNK, can complement for the ancestral MAPK Hog1 in the yeast Saccharomyces cerevisiae. S. cerevisiae mutants lacking Hog1 (hog1-Delta 1) have been complemented with the sponge SDJNK and SDp38 genes. Western blotting has revealed that, after transformation, the hog1-Delta 1+ SDJNK(sense) and hog1-Delta 1+ SDp38(sense) clones express the sponge proteins. Functional studies have demonstrated that the complemented clones grow under hyperosmotic conditions (0.6 M NaCl). Further…
A phosphorylation cycle shapes gradients of the DYRK family kinase Pom1 at the plasma membrane.
2011
http://linkinghub.elsevier.com/; International audience; Concentration gradients regulate many cell biological and developmental processes. In rod-shaped fission yeast cells, polar cortical gradients of the DYRK family kinase Pom1 couple cell length with mitotic commitment by inhibiting a mitotic inducer positioned at midcell. However, how Pom1 gradients are established is unknown. Here, we show that Tea4, which is normally deposited at cell tips by microtubules, is both necessary and, upon ectopic cortical localization, sufficient to recruit Pom1 to the cell cortex. Pom1 then moves laterally at the plasma membrane, which it binds through a basic region exhibiting direct lipid interaction. …
Effect of oxidative stress on UDP-glucuronosyltransferases in rat astrocytes.
2012
WOS:000309170300003; International audience; The present work reports data regarding effects of an induced oxidative stress on the mainly expressed isoforms of UDP-glucuronosyltransferases (UGTs) in the brain. UGT1A6 and UGT1A7 expression and enzymatic activities toward the 1-naphthol were analyzed in rat cultured astrocytes following the exposure for 48 h to redox-cycling xenobiotic compounds such as quinones and bipyridinium ions. The expression of NADPH:cytochrome P450 reductase and NAD(P)H:quinone oxidoreductase 1 (NQO1) was also investigated. Oxidative stress induced significant deleterious changes in astrocyte morphology, decreased cell viability and inhibited catalytic function of UG…
Use of CDC2 from etoposide-treated cells as substrate to assay CDC25 phosphatase activity
1999
International audience; Cyclin-dependent kinases (CDKs) regulate the key transition of the cell cycle in all organisms. In response to Etoposide (VP-16) induced DNA damage, cells undergo a G2-phase arrest resulting in the accumulation of inactive CDK1 (CDC2) kinase complexes. Here we report that upon Etoposide treatment CDC2 is phosphorylated on tyrosine 15 and is dephosphorylated and activated in vitro by recombinant CDC25 phosphatase. We also show that inactive CDC2 kinase from Etoposide-treated cells can be used as a substrate in a sensitive two-step assay of CDC25 phosphatase. This assay, which is very simple to set-up, is based on the monitoring of CDC2 kinase activity after CDC25-depe…
Increased Level of Phosphotyrosine in Human Dendritic Cells under Stimulation with Contact Sensitizers but Not Irritants
1997
In the last years evidence was presented for the activation of dendritic cells (DC) under stimulation with contact sensitizers. Most data were obtained for murine Langerhans cells (LC) whereas in man blood-derived dendritic cells were found to be a more suitable model to study the mechanism of DC activation by haptens. The first observation was the upregulation of MHC class II molecules on murine Langerhans cells in vivo1 followed by their migration from the epidermis into regional lymph nodes2. Very early events during this activation include the upregulation of IL-1s in murine LC3 as well as the endocytotic activation of this cell type4. Based on the last observation attempts were made to…
Purification, subunit structure, and kinetics of the chloroform-released F1ATPase complex from Rhodospirillum rubrum and its comparison with F1ATPase…
1979
Abstract A stable and homogeneous adenosine-5ʹ-triphosphatase (ATPase, EC 3.6.1.3) has been solubilized from Rhodospirillum rubrum (R . rubrum) chromatophores by chloroform extraction. Purification of the Ca2+-dependent ATPase activity was 200-fold. Ca2+ can be replaced by Mg2+, Cd2+, and Mn2+ .The Km for Ca-ATP (0.17 mᴍ) is increased about 5-fold during solubilization of the enzyme, whereas the Km values for Mg-ATP (0.029 mᴍ) and Cd-ATP (0.014 mᴍ) are not affected. The chloroform-released ATPase has a molecular weight of 400,000 ± 30,000 and consists of the following subunits (molecular weights in parenthesis): α (58,000), β (53,500), γ (39,000), δ (18,500), and ε (14,000). The amino acid …
Properties of the F0F1 ATPase Complex from Rhodospirillum rubrum Chromatophores, Solubilized by Triton X-100
1979
1. A cold-stable oligomycin-sensitive F0F1 ATPase complex from chromatophores of Rhodospirillum rubrum FR 1 was solubilized by Triton X-100 and purified by gel filtration. 2. The F0F1 complex is resolved by sodium dodecyl sulfate electrophoresis into 14 polypeptides with approximate molecular weights in the range of 58000--6800; five of these polypeptides are derived from the F1 moiety of the complex which carries the catalytic centers of the enzyme. 3. The purified F0F1 complex is homogeneous according to analytical ultracentrifugation and isoelectric focusing. 4. The molecular weight as determined by gel filtration is about 480 000 +/- 30 000. S020,w is 1.45 +/- 0.1 S and the pI is 5.4. 5…