Search results for "p38 mitogen-activated protein kinases"
showing 10 items of 145 documents
Effect of hypoosmotic stress by low salinity acclimation of Mediterranean mussels Mytilus galloprovincialis on biological parameters used for polluti…
2008
In the present study, we investigated the progressive acclimation of the mussel Mytilus galloprovincialis to different reduced seawater (SW) salinities and its effect on several biochemical markers and biotests. Mussels were purchased from a local mariculture facility during summer (SW temperature 27 degrees C, salinity 37.5 psu) and winter (13 degrees C, 37 psu) seasons, and transferred to the laboratory for acclimation to reduced SW salinities (37, 28, 18.5 and 11 psu). At the beginning and at the end of acclimation processes tests of mussel survival in air were provided. After 14 days of acclimation the DNA integrity, p38-MAPK activation, metallothionein induction, oxygen consumption rat…
Tristetraprolin Regulates the Expression of the Human Inducible Nitric-Oxide Synthase Gene
2005
The expression of human inducible NO synthase (iNOS) is regulated both by transcriptional and post-transcriptional mechanisms. Stabilization of mRNAs often depends on activation of p38 mitogen-activated protein kinase (p38 MAPK). In human DLD-1 cells, inhibition of p38 MAPK by the compound 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580) or by overexpression of a dominant-negative p38 MAPKalpha protein resulted in a reduction of human iNOS mRNA and protein expression, whereas human iNOS promoter activity was not affected. An important RNA binding protein regulated by the p38 MAPK pathway and involved in the regulation of the stability of several mRNAs is tr…
The collagen receptor integrins have distinct ligand recognition and signaling functions
2000
Distinct collagen subtypes are recognized by specific cell surface receptors. Two of the best known collagen receptors are members of the integrin family and are named alpha1beta1 and alpha2beta1. Integrin alpha1beta1 is abundant on smooth muscle cells, whereas the alpha2beta1 integrin is the major collagen receptor on epithelial cells and platelets. Many cell types, such as fibroblasts, osteoblasts, chondrocytes, endothelial cells, and lymphocytes may concomitantly express both of the receptors. We have studied the cell biology of these integrins at two levels. First, we have analyzed their ligand binding mechanism and specificity. Second, we have studied their signaling function inside th…
Integrin alpha 2 beta 1 promotes activation of protein phosphatase 2A and dephosphorylation of Akt and glycogen synthase kinase 3 beta.
2002
The integrins are a large family of heterodimeric transmembrane receptors composed of α and β subunits (22). In addition to mediating cell-matrix interactions, integrins have been shown to activate intracellular signaling pathways which, in collaboration with growth factor-induced signals, regulate cellular functions (46). Some integrin signaling cascades are activated via the β subunit cytoplasmic domain, and they are therefore triggered by several integrin heterodimers. These signals include the activation of protein tyrosine kinases of the Src and focal adhesion kinase (FAK) families (9, 47). More-recent studies have revealed signaling events that are activated specifically by an α subun…
Differential role of p38 mitogen activated protein kinase for cellular recovery from attack by pore-forming S. aureus alpha-toxin or streptolysin O.
2006
Following the observation that cells are able to recover from membrane lesions incurred by Staphylococcus aureus alpha-toxin and streptolysin O (SLO), we investigated the role of p38 in this process. p38 phosphorylation occurred in response to attack by both toxins, commencing within minutes after toxin treatment and waning after several hours. While SLO reportedly activates p38 via ASK1 and ROS, we show that this pathway does not play a major role for p38 induction in alpha-toxin-treated cells. Strikingly divergent effects of p38 blockade were noted depending on the toxin employed. In the case of alpha-toxin, inhibition of p38 within the time frame of its activation led to disruption of th…
Studies of Jak/STAT3 expression and signalling in psoriasis identifies STAT3-Ser727 phosphorylation as a modulator of transcriptional activity
2013
Jak/Tyk proteins have recently aroused as possible therapeutic targets for the treatment of psoriasis. In psoriasis, these proteins signal through STAT molecules including STAT3, and STAT3 expression and activation has been shown augmented in psoriatic lesions. Here, we characterized the expression of Jak/Tyk proteins in lesional compared with non-lesional psoriatic skin. Jak1, Jak2 mRNA and protein and Tyk2 mRNA appeared to be downregulated, whereas Jak3 mRNA expression was increased. Moreover, STAT3 expression and activation was examined in psoriasis. STAT3 is activated at two phosphorylation sites: Tyr705 and Ser727. Both phosphorylation sites were phosphorylated in lesional psoriatic sk…
STAT1 expression and activation is increased in lesional psoriatic skin
2013
Summary Background The JAK (Janus kinase)/STAT (signal transducer and activator of transcription) signalling pathway is known to play an important role in many cellular processes including inflammation. The activation of STAT1 is dependent on tyrosine 701 and serine 727 phosphorylation, which leads to the formation of the STAT dimer and modulation of STAT1 activity, respectively. Objective To determine STAT1 expression and activation in psoriatic skin. Methods Biopsies were collected from patients with psoriasis. mRNA expression was evaluated by quantitative polymerase chain reaction, whereas the protein and phosphorylation level of STAT1 were evaluated by Western blotting. STAT1 localiz…
HSP27 controls GATA-1 protein level during erythroid cell differentiation.
2010
AbstractHeat shock protein 27 (HSP27) is a chaperone whose cellular expression increases in response to various stresses and protects the cell either by inhibiting apoptotic cell death or by promoting the ubiquitination and proteasomal degradation of specific proteins. Here, we show that globin transcription factor 1 (GATA-1) is a client protein of HSP27. In 2 models of erythroid differentiation; that is, in the human erythroleukemia cell line, K562 induced to differentiate into erythroid cells on hemin exposure and CD34+ human cells ex vivo driven to erythroid differentiation in liquid culture, depletion of HSP27 provokes an accumulation of GATA-1 and impairs terminal maturation. More spec…
2′O-galloylhyperin attenuates LPS-induced acute lung injury via up-regulation antioxidation and inhibition of inflammatory responses in vivo
2019
2'O-galloylhyperin, an active flavonol glycoside compound with remarkable anti-immune activity, was isolated from Pyrola [P. incarnata Fisch.]. However, the evidence of anti-inflammatory activity in pulmonary diseases was still not convincing. The aim of the present study was (1) to investigate the effect of 2'O-galloylhyperin on LPS-induced acute lung injury in mice, and (2) to identify the mechanisms of attenuation of inflammatory responses. The results demonstrated that 2'O-galloylhyperin significantly reduced LPS-induced inflammation damage in a dose-dependent manner. After LPS challenge, treatment with 2'O-galloylhyperin reduced the production of pro-inflammatory cytokines and chemokin…
Quaking and miR-155 interactions in inflammation and leukemogenesis.
2015
Quaking (QKI) is a tumor-suppressor gene encoding a conserved RNA-binding protein, whose expression is downregulated in several solid tumors. Here we report that QKI plays an important role in the immune response and suppression of leukemogenesis. We show that the expression of Qki is reduced in lipopolysaccharide (LPS)-challenged macrophages, suggesting that Qki is a key regulator of LPS signaling pathway. Furthermore, LPS-induced downregulation of Qki expression is miR-155-dependent. Qki overexpression impairs LPS-induced phosphorylation of JNK and particularly p38 MAPKs, in addition to increasing the production of anti-inflammatory cytokine IL-10. In contrast, Qki ablation decreases Fas …