Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclic AMP and cell swelling stimulate hepatic Na+/TC cotransport and Ntcp translocation via the phosphoinositide 3-kinase signaling pathway. To determine the downstream target of the phosphoinositide 3-kinase action, we examined the role of protein kinase B (PKB)/Akt using SB203580 in hepatocytes as well as by transfection with a dominant negative (DN-PKB) or a constitutively active (CA-PKB) form of PKB in HuH-Ntcp cells. Both cAMP and cell swelling stimulated p38 mitogen-activated protein (MAP) kinase as well as PKB activity. Although 100 microm SB203580 inhibited cell swelling- and 8-chlorophenylthio-cAMP-induced activation of both p38 MAP kinase and PKB, 1 microm SB203580 inhibited activation of p38 MAP kinase, but not of PKB, in hepatocytes. 100 microm, but not 1 microm SB203580, inhibited cell swelling- and cAMP-induced increases in taurocholate (TC) uptake and Ntcp translocation in hepatocytes. TC uptake in HuH-Ntcp cells was more than 90% dependent on extracellular Na+. Cyclic AMP and cell swelling increased TC uptake by 50-100% and PKB activity 2-4-fold in HuH-Ntcp cells transfected with the empty vector and failed to increase PKB activity, TC uptake, and Ntcp translocation in DN-PKB-transfected HuH-Ntcp cells. Transfection with CA-PKB increased PKB activity, TC uptake, and Ntcp translocation in HuH-Ntcp cells compared with cells transfected with the empty vector. In contrast, transfection with DN-PKB did not affect basal PKB activity, TC uptake, or Ntcp translocation. Taken together, these results strongly suggest that cell swelling and cAMP-mediated stimulation of hepatic Na+/TC cotransport and Ntcp translocation requires activation of PKB and is mediated at least in part via a phosphoinositide 3-kinase/PKB-signaling pathway.
 ...
PMID:Protein kinase B/Akt mediates cAMP- and cell swelling-stimulated Na+/taurocholate cotransport and Ntcp translocation. 1203 24

The angiotensin AT(1) and AT(2) receptors have been cloned and characterised. Both are members of the serpentine receptor superfamily coupled to G proteins, but there is only 32% homology between the AT(1) and AT(2) receptors. The typical pharmacological features of AT(1) receptors are their selective affinity for biphenylimidazoles (typified by losartan) and their insensitivity to tetrahydroimidazopyridine (such as PD123319). In contrast, the AT(2) receptor has the opposite sensitivity for these two ligands. Genes located on chromosome 3 and X, respectively, encode the human AT(1) and AT(2) receptors. The signalling pathways of AT(1) and AT(2) are totally different. In addition to the classical signal transduction mechanisms (phospholipases C, D, A, voltage-dependent calcium channels and adenylate cyclase), the AT(1) receptor stimulates the phosphorylation of several tyrosine-containing proteins such as Jak 2, Stat 1 and mitogen-activated protein kinases. It also activates the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. The AT(1) receptor is responsible for the majority of the effects of angiotensin II: vasoconstriction, sodium re-absorption, cell proliferation, extracellular matrix formation, inflammatory response and oxidative stress. The AT(2) receptor is expressed abundantly in fetal tissues but at low density in adults. It is, however, upregulated in various pathological circumstances such as heart failure. In contrast to the AT(1) receptor, the signalling pathway of the AT(2) receptor does not induce an increase in inositol triphosphate and diacylglycerate formation with calcium mobilisation. Activation of the AT(2) receptor stimulates an intracellular mechanism involving various Tyr (tyrosine) and Ser (serine)/Thr (threonine) phosphatases, nitric oxide/cyclic guanosine monophosphate (cGMP) and phospholipase A(2). The effect of the AT(2) receptor counterbalances that of the AT(1) receptor: inactivation of mitogen-activated protein kinase (MAP), antiproliferation, promotion of apoptosis, opening of delayed-rectifier K(+) channels, closing of T-type Ca(2+) channels, stimulation of nerve differentiation and regeneration. It has been hypothesised that stimulation of the AT(2) receptor is part of the mechanism of action of the AT(1) receptor antagonists.
 ...
PMID:[AT(1) and AT(2) angiotensin II receptors: key features]. 1203 84

The CC chemokine eotaxin is a potent eosinophil-specific chemoattractant that is crucial for allergic inflammation. Allergen-induced tumour necrosis factor (TNF) has been shown to induce eotaxin synthesis in eosinophils. Nuclear factor-kappaB (NF-kappaB) and mitogen-activated protein kinases (MAPK) have been found to play an essential role for the eotaxin-mediated eosinophilia. We investigated the modulation of NF-kappaB and MAPK activation in TNF-induced eotaxin release of human eosinophils. Human blood eosinophils were purified from fresh buffy coat using magnetic cell sorting. NF-kappaB pathway-related genes were evaluated by cDNA expression array system. Degradation of IkappaBalpha and phosphorylation of MAPK were detected by Western blot. Activation of NF-kappaB was determined by electrophoretic mobility shift assay. Eotaxin released into the eosinophil culture medium was measured by ELISA. TNF was found to up-regulate the gene expression of NF-kappaB and IkappaBalpha in eosinophils. TNF-induced IkappaBalpha degradation was inhibited by the proteasome inhibitor N-cbz-Leu-Leu-leucinal (MG-132) and a non-steroidal anti-inflammatory drug sodium salicylate (NaSal). Using EMSA, both MG-132 and NaSal were found to suppress the TNF-induced NF-kappaB activation in eosinophils. Furthermore, TNF was shown to induce phosphorylation of p38 MAPK time-dependently but not extracellular signal-regulated kinases (ERK). Inhibition of NF-kappaB activation and p38 MAPK activity decreased the TNF-induced release of eotaxin from eosinophils. These results indicate that NF-kappaB and p38 MAPK play an important role in TNF-activated signalling pathway regulating eotaxin release by eosinophils. They have also provided a biochemical basis for the potential of using specific inhibitors of NF-kappaB and p38 MAPK for treating allergic inflammation.
 ...
PMID:Activation of p38 mitogen-activated protein kinase and nuclear factor-kappaB in tumour necrosis factor-induced eotaxin release of human eosinophils. 1206 3

Adenosine is released from the myocardium, endothelial cells, and skeletal muscle in ischemia and is an important regulator of coronary blood flow. We have already shown that acute (2 min) activation of A2a purinoceptors stimulates NO production in human fetal umbilical vein endothelial cells (1) and now report a key role for p42/p44 mitogen-activated protein kinases (p42/p44MAPK) in the regulation of the l-arginine-nitric oxide (NO) signaling pathway. Expression of mRNA for the A2a-, A2b-, and A3-adenosine receptor subtypes was abundant whereas A1-adenosine receptor mRNA levels were negligible. Activation of A2a purinoceptors by adenosine (10 microM) or the A2a receptor agonist CGS21680 (100 nM) resulted in an increase in l-arginine transport and NO release that was not mediated by changes in intracellular Ca2+, pH, or cAMP. Stimulation of endothelial cells with adenosine was associated with a membrane hyperpolarization and phosphorylation of p42/p44MAPK. l-NAME abolished the adenosine-induced hyperpolarization and stimulation of l-arginine transport whereas sodium nitroprusside activated an outward potassium current. Genistein (10 microM) and PD98059 (10 microM), an inhibitor of MAPK kinase 1/2 (MEK1/2), inhibited adenosine-stimulated l-arginine transport, NO production, and phosphorylation of p42/p44MAPK. We found no evidence for activation of eNOS via the serine/threonine kinase Akt/PKB (protein kinase B) in adenosine-stimulated cells. Our results provide the first evidence that adenosine stimulates the endothelial cell l-arginine-NO pathway in a Ca2+-insensitive manner involving p42/p44MAPK, with release of NO leading to a membrane hyperpolarization and activation of l-arginine transport.
 ...
PMID:Early activation of the p42/p44MAPK pathway mediates adenosine-induced nitric oxide production in human endothelial cells: a novel calcium-insensitive mechanism. 1237 81

Previous studies have demonstrated that haptens induce several phenotypic and functional changes of dendritic cells in vivo as well as in vitro. Although recently, the crucial role of p38 mitogen-activated protein kinase has been reported in the activation of dendritic cells by haptens, the signal transduction elements involved in each phenotypic and functional changes that occur in the activation of dendritic cells by haptens remain unknown. Therefore, we examined the role of mitogen-activated protein kinases and nuclear factor-kappaB in the signal transduction of dendritic cells stimulated with two representative haptens, i.e., NiCl2 and 2,4-dinitrochlorobenzene. Human monocyte-derived dendritic cells stimulated with 2,4-dinitrochlorobenzene induced the phosphorylation of p38 and stress-activated protein kinase/c-jun N-terminal kinases, whereas NiCl2 induced that of p44/42 extracellular signal-regulated kinases, p38, and stress-activated protein kinase/c-jun N-terminal kinases. In addition, NiCl2 phosphorylated inhibitor kappaB and activated nuclear factor-kappaB. In contrast, primary irritants, e.g., benzalkonium chloride, or sodium lauryl sulfate, did not activate these signal transduction pathways. By using specific inhibitors for extracellular signal-regulated kinases and p38 pathways, PD98059 and SB203580, respectively, we demonstrated that the augmentation of CD86, HLA-DR, and CD83, and the production of interleukin-8 along with its increased mRNA expression by monocyte-derived dendritic cells stimulated with 2,4-dinitrochlorobenzene, and the augmentation of CD83 and the interleukin-12 p40 production by monocyte-derived dendritic cells stimulated with NiCl2, were suppressed by SB203580, whereas PD98059 suppressed the production of interleukin-1beta and tumor necrosis factor-alpha, together with their increased mRNA expression by monocyte-derived dendritic cells treated with NiCl2. On the other hand, in spite of the activation of nuclear factor-kappaB by monocyte-derived dendritic cells stimulated with NiCl2, nuclear factor-kappaB inhibitor did not significantly affect the phenotypic and functional changes in the activation of monocyte-derived dendritic cells. These data indicate that NiCl2 and 2,4-dinitrochlorobenzene stimulate different signal transduction pathways in monocyte-derived dendritic cells, and subsequently induce different phenotypic and functional changes in them.
 ...
PMID:p38 Mitogen-activated protein kinase and extracellular signal-regulated kinases play distinct roles in the activation of dendritic cells by two representative haptens, NiCl2 and 2,4-dinitrochlorobenzene. 1260 67

Heme oxygenase-1 (HO-1) gene expression is induced by various oxidative stress stimuli including sodium arsenite. Since mitogen-activated protein kinases (MAPKs) are involved in stress signaling we investigated the role of arsenite and MAPKs for HO-1 gene regulation in primary rat hepatocytes. The Jun N-terminal kinase (JNK) inhibitor SP600125 decreased sodium arsenite-mediated induction of HO-1 mRNA expression. HO-1 protein and luciferase activity of reporter gene constructs with -754 bp of the HO-1 promoter were induced by overexpression of kinases of the JNK pathway and MKK3. By contrast, overexpression of Raf-1 and ERK2 did not affect expression whereas overexpression of p38alpha, beta, and delta decreased and p38gamma increased HO-1 expression. Electrophoretic mobility shift assays (EMSA) revealed that a CRE/AP-1 element (-668/-654) bound c-Jun, a target of the JNK pathway. Deletion or mutation of the CRE/AP-1 obliterated the JNK- and c-Jun-dependent up-regulation of luciferase activity. EMSA also showed that an E-box (-47/-42) was bound by a putative p38 target c-Max. Mutation of the E-box strongly reduced MKK3, p38 isoform-, and c-Max-dependent effects on luciferase activity. Thus, the HO-1 CRE/AP-1 element mediates HO-1 gene induction via activation of JNK/c-Jun whereas p38 isoforms act through a different mechanism via the E-box.
 ...
PMID:Transcriptional regulation of heme oxygenase-1 gene expression by MAP kinases of the JNK and p38 pathways in primary cultures of rat hepatocytes. 1263 67

To investigate synaptic formation of neurons grown on three-dimensional (3D) collagen gels, neurons dissociated from embryonic rat cerebral cortices were seeded onto type-I collagen gels and cultured in serum-free medium for up to 2 weeks. Double-immunostaining for mitogen-activated protein-2 (MAP-2), a neuronal cell body and dendritic marker, and synapsin I, a synaptic vesicle antigen, was carried out to identify pre- and postsynaptic structural specializations, respectively. MAP-2(+) neuronal soma and dendrites were found to be surrounded by numerous puncta of synapsin I in a 1 week-old culture. Whole-cell patch clamp experiments demonstrated that the neurons grown on 3D gels exhibit sodium and potassium currents similar to those seen in 2D culture. Spontaneous action potentials were found in neurons that had been in culture for 8-12 days. In addition, spontaneous, bicuculline-sensitive gamma-aminobutyric acidergic postsynaptic currents were also present. This is the first demonstration of functional synapse formation among neurons grown on 3D collagen gels, suggesting that type-I collagen can be a promising material for neuronal regeneration.
 ...
PMID:Functional synapse formation among rat cortical neurons grown on three-dimensional collagen gels. 1267 33

Although it is known that diabetic nephropathy is accelerated by hypertension, the mechanisms involved in this process are not clear. In this study we aimed to clarify these mechanisms using male Wistar fatty rats (WFR) as a type 2 diabetic model and male Wistar lean rats (WLR) as a control. Each group was fed a normal or high sodium diet from the age of 6 to 14 weeks. We determined the blood pressure and urinary albumin excretion (UAE). At the end of the study, the expressions of mitogen-activated protein kinases (MAPK) and transforming growth factor-beta1 (TGF-beta1) were examined in the isolated glomeruli by Western blot analysis, and the number of glomerular lesions was determined by conventional histology. High sodium load caused hypertension and a marked increase in UAE in the WFR but not in the WLR. Glomerular volume was increased in the hypertensive WFR. There was no difference among the four groups in the expression of c-Jun-NH2-terminal kinase (JNK). In contrast, the expressions of extracellular signal-regulated kinase 1/2 (ERK1/2) and its upstream regulator, MAPK/ERK kinase 1 (MEK1), were augmented in the hypertensive WFR. Expression of p38 MAPK was increased in the normotensive WFR, and further enhanced in the hypertensive WFR. Moreover, administration of high sodium load to WFR augmented the expression of TGF-beta1. In conclusion, systemic hypertension in WFR accelerates the diabetic nephropathy in type 2 diabetes via MEK-ERK and p38 MAPK cascades. TGF-beta1 is also involved in this mechanism.
 ...
PMID:Hypertension accelerates diabetic nephropathy in Wistar fatty rats, a model of type 2 diabetes mellitus, via mitogen-activated protein kinase cascades and transforming growth factor-beta1. 1273 3

Glutathione S-transferase pi (GSTpi; EC 2.5.1.18) has been shown recently to be a regulator of mitogen-activated protein kinases (MAPK). We have developed, by chronic exposure of HL60 cells to increasing concentrations of a peptidomimetic GSTpi inhibitor TLK199, a 10-fold resistant cell line (HL60/TLK199). Among the cellular adaptations observed in this cell line was an increase in extracellular signal-regulated kinase (ERK) activity without modification of basal expression levels. Phorbol 12-myristate 13-acetate (PMA) induced monocyte/macrophage cytodifferentiation in both HL60 wild-type (WT) and HL60/TLK199 cells. In contrast, PMA induced a pronounced cell growth inhibition and G(0)/G(1) cell cycle arrest in HL60 WT cells, while this differentiating agent had only a mild effect on cell growth without G(0)/G(1) cell cycle arrest in HL60/TLK199. This effect was associated with a rapid and sustained activation of ERK (up to 6hr) in HL60 WT cells but only a transient induction of these kinases (between 30 and 60min) in HL60/TLK199. Furthermore, treatment of both cell lines with PMA in combination with the protein tyrosine phosphatase inhibitors sodium orthovanadate (OV) or 3,4-dephostatin (DPN) circumvented the resistance to cell growth arrest and potentiated differentiation in HL60/TLK199 but had no effect on HL60 WT cells. The circumvention of the resistance to PMA was associated with a sustained activation of ERK. These data suggest that chronic exposure of HL60 cells to TLK199 alters cellular ERK activation by PMA, which may contribute to the differential response of the WT and resistant cells to PMA.
 ...
PMID:Resistance to phorbol 12-myristate 13-acetate-induced cell growth arrest in an HL60 cell line chronically exposed to a glutathione S-transferase pi inhibitor. 1275 97

For many years investigators have been researching methods of preconditioning the myocardium against ischaemia-induced damage; however, a majority of this research has been carried out in young animals and cells. Normal ageing is accompanied by changes in the human myocardium that decrease its capacity to tolerate and respond to various forms of stress. Also, the likelihood of experiencing an ischaemic stress and other cardiovascular complications increases as an individual ages; therefore, an aged population would benefit most from cardioprotective treatments. Methods currently known to provide cardioprotection (or preconditioning) include exercise, heat stress, oxidative stress, brief ischaemia, stretch and certain pharmacological interventions. It is unclear whether the aged myocardium can adapt to a preconditioning stimulus; however, many researchers have observed age-related alterations in the expression and activation of proteins key to the cardioprotective process. These proteins include heat shock protein 70 (HSP70), nitric oxide synthase (NOS), the sodium-hydrogen exchanger (NHE), and the mitogen-activated protein (MAP) kinases c-Jun N-terminal Kinase (JNK), extracellular signal-regulated kinase (ERK), and p38. Therefore, the purpose of the current review will be to outline the current knowledge of these cardioprotective agents in an aged myocardium. Interactions among the cardioprotective agents outlined herein suggest that age-related changes in the myocardium will need to be better understood before cardioprotective interventions that have been proved effective in young animals can be applied to an aged human population.
 ...
PMID:Age, cell signalling and cardioprotection. 1278 Mar 84


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>