Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat p38 mitogen-activated protein (MAP) kinase cDNA was isolated from rat kidney cDNA library using a PCR cloning strategy. The deduced amino acid sequence consists of 360 amino acids and shares 95.3% similarity with human p38 MAP kinase. The message for rat p38 MAP kinase was about 3.4 kilobases and was highly expressed in the kidney. In water-deprived rat kidneys, the steady-state levels of p38 MAP kinase mRNA increased about 2.7-fold as compared with those of control rats. This result suggests that p38 MAP kinase may play an important role in the osmoregulation in the kidney.
Biochem Mol Biol Int 1997 Sep
PMID:Molecular cloning of rat p38 mitogen-activated protein kinase and it's osmotic regulation in rat kidney. 931 83

The adverse effects of lipopolysaccharide (LPS) are mediated primarily by tumor necrosis factor alpha (TNF-alpha). TNF-alpha production by LPS-stimulated macrophages is regulated at the levels of both transcription and translation. It has previously been shown that several mitogen-activated protein kinases (MAPKs) are activated in response to LPS. We set out to determine which MAPK signaling pathways are activated in our system and which MAPK pathways are required for TNF-alpha gene transcription or TNF-alpha mRNA translation. We confirm activation of the MAPK family members extracellular-signal-regulated kinases 1 and 2 (ERK1 and ERK2), p38, and Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), as well as activation of the immediate upstream MAPK activators MAPK/ERK kinases 1 and 4 (MEK1 and MEK4). We demonstrate that LPS also activates MEK2, MEK3, and MEK6. Furthermore, we demonstrate that dexamethasone, which inhibits the production of cytokines, including TNF-alpha, significantly inhibits LPS induction of JNK/SAPK activity but not that of p38, ERK1 and ERK2, or MEK3, MEK4, or MEK6. Dexamethasone also blocks the sorbitol but not anisomycin stimulation of JNK/SAPK activity. A kinase-defective mutant of SAPKbeta, SAPKbeta K-A, blocked translation of TNF-alpha, as determined by using a TNF-alpha translational reporting system. Finally, overexpression of wild-type SAPKbeta was able to overcome the dexamethasone-induced block of TNF-alpha translation. These data confirm that three MAPK family members and their upstream activators are stimulated by LPS and demonstrate that JNK/SAPK is required for LPS-induced translation of TNF-alpha mRNA. A novel mechanism by which dexamethasone inhibits translation of TNF-alpha is also revealed.
Mol Cell Biol 1997 Nov
PMID:Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) is required for lipopolysaccharide stimulation of tumor necrosis factor alpha (TNF-alpha) translation: glucocorticoids inhibit TNF-alpha translation by blocking JNK/SAPK. 934 88

Recent studies have indicated that serine phosphorylation regulates the activities of STAT1 and STAT3. However, the kinase(s) responsible and the role of serine phosphorylation in STAT function remain unresolved. In the present studies, we examined the growth factor-dependent serine phosphorylation of STAT1 and STAT3. We provide in vitro and in vivo evidence that the ERK family of mitogen-activated protein (MAP) kinases, but not JNK or p38, specifically phosphorylate STAT3 at serine 727 in response to growth factors. Evidence for additional mitogen-regulated serine phosphorylation is also provided. STAT1 is a relatively poor substrate for all MAP kinases tested both in vitro and in vivo. STAT3 serine phosphorylation, not its tyrosine phosphorylation, results in retarded mobility of the STAT3 protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Importantly, serine 727 phosphorylation negatively modulates STAT3 tyrosine phosphorylation, which is required for dimer formation, nuclear translocation, and the DNA binding activity of this transcriptional regulator. Interestingly, the cytokine interleukin-6 also stimulates STAT3 serine phosphorylation, but in contrast to growth factors, this occurs by an ERK-independent process.
Mol Cell Biol 1997 Nov
PMID:STAT3 serine phosphorylation by ERK-dependent and -independent pathways negatively modulates its tyrosine phosphorylation. 934 14

At least three mitogen-activated protein kinase (MAPK) cascades were identified in mammals, each consisting of a well-defined three-kinase module composed of a MAPK, a MAPK kinase (MAPKK), and a MAPKK kinase (MAPKKK). These cascades play key roles in relaying various physiological, environmental, or pathological signals from the environment to the transcriptional machinery in the nucleus. One of these MAPKs, c-Jun N-terminal kinase (JNK), stimulates the transcriptional activity of c-Jun in response to growth factors, proinflammatory cytokines, and certain environmental stresses, such as short wavelength UV light or osmotic shock. The JNKs are directly activated by the MAPKK JNKK1/SEK1/MKK4. However, inactivation of the gene encoding this MAPKK by homologous recombination suggested the existence of at least one more JNK-activating kinase. Recently, the JNK cascade was found to be structurally and functionally conserved in Drosophila, where DJNK is activated by the MAPKK DJNKK (hep). By a database search, we identified an expressed sequence tag (EST) encoding a portion of human MAPKK that is highly related to DJNKK (hep). We used this EST to isolate a full-length cDNA clone encoding a human JNKK2. We show that JNKK2 is a highly specific JNK kinase. Unlike JNKK1, it does not activate the related MAPK, p38. Although the regulation of JNKK1 activities and that of JNKK2 activities could be very similar, the two kinases may play somewhat different regulatory roles in a cell-type-dependent manner.
Mol Cell Biol 1997 Dec
PMID:Molecular cloning and characterization of human JNKK2, a novel Jun NH2-terminal kinase-specific kinase. 937 71

We characterized participation of the stress-activated protein kinase (SAPK) cascade in the lethal actions of the cytotoxic lipid messengers ceramide and sphingosine in U937 human monoblastic leukemia cells. Acute exposure of U937 cells to either lipid resulted in loss of proliferative capacity, degradation of genomic DNA, and manifestation of apoptotic cytoarchitecture. Ceramide robustly stimulated p46-JNK1/p54-JNK2 activity and increased expression of c-jun mRNA and c-Jun protein; in contrast, sphingosine moderately stimulated p46-JNK1/p54-JNK2 and failed to modify c-jun/c-Jun expression. Dominant-negative blockade of normal c-Jun activity by transfection with the TAM-67 c-Jun NH2-terminal deletion mutant abolished the lethal actions of ceramide but was without effect on those of sphingosine, indicating that ceramide-related apoptosis is directly dependent on activation of c-Jun, whereas sphingosine-induced cell death proceeds via an unrelated downstream mechanism. Characterization of the mitogen-activated protein kinase (MAPK) cascade in these responses revealed a further functional disparity between the two lipids: basal p42-ERK1/ p44-ERK2 activity was gradually reduced by ceramide but immediately and completely suppressed by sphingosine. Moreover, blockade of the MAPK cascade by the aminomethoxyflavone MEK1 inhibitor PD-98059 unexpectedly activated p46-JNK1/p54-JNK2 and induced apoptosis in a manner qualitatively resembling that of sphingosine. Both lipids sharply increased p38-RK activity; selective pharmacological inhibition of p38-RK by the pyridinyl imidazole SB-203580 failed to mitigate the cytotoxicity associated with either ceramide or sphingosine, suggesting that p38-RK is not essential for lipid-induced apoptosis. These findings demonstrate that reciprocal alterations in the SAPK and MAPK cascades are associated with the apoptotic influence of either lipid inasmuch as (i) ceramide-mediated lethality is primarily associated with strong stimulation of SAPK and weak inhibition of MAPK, whereas (ii) sphingosine-mediated lethality is primarily associated with weak stimulation of SAPK and strong inhibition of MAPK. We therefore propose that leukemic cell survival depends on the maintenance of an imbalance of the outputs from the MAPK and SAPK systems such that the dominant basal influence of the MAPK cascade allows sustained proliferation, whereas acute redirection of this balance toward the SAPK cascade initiates apoptotic cell death.
Mol Pharmacol 1997 Dec
PMID:Coordinate regulation of stress- and mitogen-activated protein kinases in the apoptotic actions of ceramide and sphingosine. 941 3

Many actions of the proinflammatory cytokines tumor necrosis factor (TNF) and interleukin-1 (IL-1) on gene expression are mediated by the transcription factor NF-kappaB. Activation of NF-kappaB by TNF and IL-1 is initiated by the phosphorylation of the inhibitory subunit, IkappaB, which targets IkappaB for degradation and leads to the release of active NF-kappaB. The nonsteroidal anti-inflammatory drug sodium salicylate (NaSal) interferes with TNF-induced NF-kappaB activation by inhibiting phosphorylation and subsequent degradation of the IkappaB alpha protein. Recent evidence indicated that NaSal activates the p38 mitogen-activated protein kinase (MAPK), raising the possibility that inhibition of NF-kappaB activation by NaSal is mediated by p38 MAPK. We now show that inhibition of TNF-induced IkappaB alpha phosphorylation and degradation by NaSal is prevented by treatment of cells with SB203580, a highly specific p38 MAPK inhibitor. Both p38 activation and inhibition of TNF-induced IkappaB alpha degradation were seen after only 30 s to 1 min of NaSal treatment. Induction of p38 MAPK activation and inhibition of TNF-induced IkappaB alpha degradation were demonstrated with pharmacologically achievable doses of NaSal. These findings provide evidence for a role of NaSal-induced p38 MAPK activation in the inhibition of TNF signaling and suggest a possible role for the p38 MAPK in the anti-inflammatory actions of salicylates. In addition, these results implicate the p38 MAPK as a possible negative regulator of TNF signaling that leads to NF-kappaB activation.
Mol Cell Biol 1998 Jan
PMID:Activation of p38 mitogen-activated protein kinase by sodium salicylate leads to inhibition of tumor necrosis factor-induced IkappaB alpha phosphorylation and degradation. 941 55

The fission yeast Sty1 mitogen-activated protein (MAP) kinase (MAPK) and its activator the Wis1 MAP kinase kinase (MAPKK) are required for cell cycle control, initiation of sexual differentiation, and protection against cellular stress. Like the mammalian JNK/SAPK and p38/CSBP1 MAPKs, Sty1 is activated by a range of environmental insults including osmotic stress, hydrogen peroxide, UV light, menadione, heat shock, and the protein synthesis inhibitor anisomycin. We have recently identified two upstream regulators of the Wis1 MAPKK, namely the Wak1 MAPKKK and the Mcs4 response regulator. Cells lacking Mcs4 or Wak1, however, are able to proliferate under stressful conditions and undergo sexual differentiation, suggesting that additional pathway(s) control the Wis1 MAPKK. We now show that this additional signal information is provided, at least in part, by the Win1 mitotic regulator. We show that Wak1 and Win1 coordinately control activation of Sty1 in response to multiple environmental stresses, but that Wak1 and Win1 perform distinct roles in the control of Sty1 under poor nutritional conditions. Our results suggest that the stress-activated Sty1 MAPK integrates information from multiple signaling pathways.
Mol Biol Cell 1998 Feb
PMID:The Win1 mitotic regulator is a component of the fission yeast stress-activated Sty1 MAPK pathway. 945 Sep 57

The tumor promoter palytoxin has been found to activate the stress-activated protein kinase/c-Jun NH2-terminal kinase 1 (SAPK/JNK1), and it also potentiates, as demonstrated here, the p38/HOG1 mitogen-activated protein kinase and the upstream activator of SAPK/JNK1, SEK1/MKK4. In search of possible mechanisms for both the cytotoxicity and the activation of stress kinases by palytoxin, we found that palytoxin is a potent inhibitor of cellular protein synthesis. The inhibition of translation by palytoxin does not result from its direct binding to the translational apparatus. We have previously demonstrated that ribotoxic stressors (Iordanov, M. S., Pribnow, D., Magun, J. L., Dinh, T.-H., Pearson, J. A., Chen, S. L.-Y., and Magun, B. E. (1997) Mol. Cell. Biol. 17, 3373-3381) signal the activation of SAPK/JNK1 by binding to or covalently modifying 28 S rRNA in ribosomes that are active at the time of exposure to the stressor. Palytoxin acted as a ribotoxic stressor, inasmuch as it required actively translating ribosomes at the time of exposure to activate SAPK/JNK1. Palytoxin has been shown to augment ion fluxes by binding to the Na+/K+-ATPase in the plasma membrane of cells. To determine whether altered fluxes of either Na+ or K+ could be responsible for the effects of palytoxin on translation and on activation of SAPK/JNK1, cells were exposed to palytoxin in modified culture medium in which a major portion of the Na+ was replaced by either K+ or by choline+. The substitution of Na+ by K+ strongly inhibited the ability of palytoxin both to inhibit protein translation and to activate SAPK/JNK1, whereas the substitution of Na+ by choline+ did not. These results suggest that palytoxin-induced efflux of cellular K+ mimics ribotoxic stress by provoking both translational inhibition and activation of protein kinases associated with cellular defense against stress.
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PMID:Loss of cellular K+ mimics ribotoxic stress. Inhibition of protein synthesis and activation of the stress kinases SEK1/MKK4, stress-activated protein kinase/c-Jun NH2-terminal kinase 1, and p38/HOG1 by palytoxin. 945 78

The Mas oncogene encodes a novel G-protein-coupled receptor that was identified originally as a transforming protein when overexpressed in NIH 3T3 cells. The mechanism and signaling pathways that mediate Mas transformation have not been determined. We observed that the foci of transformed NIH 3T3 cells caused by Mas were similar to those caused by activated Rho and Rac proteins. Therefore, we determined if Mas signaling and transformation are mediated through activation of a specific Rho family protein. First, we observed that, like activated Rac1, Mas cooperated with activated Raf and caused synergistic transformation of NIH 3T3 cells. Second, both Mas- and Rac1-transformed NIH 3T3 cells retained actin stress fibers and showed enhanced membrane ruffling. Third, like Rac, Mas induced lamellipodium formation in porcine aortic endothelial cells. Fourth, Mas and Rac1 strongly activated the JNK and p38, but not ERK, mitogen-activated protein kinases. Fifth, Mas and Rac1 stimulated transcription from common DNA promoter elements: NF-kappaB, serum response factor (SRF), Jun/ATF-2, and the cyclin D1 promoter. Finally, Mas transformation and some of Mas signaling (SRF and cyclin D1 but not NF-kappaB activation) were blocked by dominant negative Rac1. Taken together, these observations suggest that Mas transformation is mediated in part by activation of Rac-dependent signaling pathways. Thus, Rho family proteins are common mediators of transformation by a diverse variety of oncogene proteins that include Ras, Dbl family, and G-protein-coupled oncogene proteins.
Mol Cell Biol 1998 Mar
PMID:Mas oncogene signaling and transformation require the small GTP-binding protein Rac. 948 37

Suppression Subtractive Hybridization (SSH) has been used to compare rat Nb2 cells treated with prolactin for 1 hour with untreated cells. This new method for identifying differentially expressed genes showed that the mRNAs for at least three genes were elevated by such treatment, including a p38 mitogen activated protein (MAP) kinase. The p38 MAP kinase was cloned and the full length cDNA sequence was determined.
J Mol Endocrinol 1998 Feb
PMID:Suppression subtractive hybridization (SSH) identifies prolactin stimulation of p38 MAP kinase gene expression in Nb2 T lymphoma cells: molecular cloning of rat p38 MAP kinase. 951 91


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