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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)
Sodium fluoride (NaF) has previously been reported to induce a strong IL-8 response in human epithelial lung cells (A549) via mechanisms that seem to involve the activation of G proteins. In the present study the signal pathways downstream of the G proteins have been examined. NaF induced a weak, but sustained increase in PKC activity. In contrast, the PKC activator TPA induced a relatively strong, but transient effect and augmented the NaF-induced PKC activity. TPA induced a marked IL-8 response compared to NaF. PDB, another PKC activator, was less effective, but augmented the IL-8 response to NaF. Pretreatment with TPA for 20 h, or the PKC inhibitor GF109203X for 1 h, abolished the basal and NaF-induced PKC activities and partially prevented the NaF-induced IL-8 response. Inhibition of the MAP kinase p38 by SB202190 partially reduced the IL-8 response to NaF, whereas a reduction in ERK activity by PD98059 led to an increased response. The NaF-induced IL-8 response was weakly augmented by the
PKA
stimulator forskolin and the G(i) inhibitor pertussis toxin. The
PKA
inhibitor H89 seemed to reduce the NaF-induced IL-8 response, but the measured effect was not statistically significant. BAPTA-AM, KN93 and W7, that inhibit Ca(2+)-linked effects, did not affect the IL-8 response. Furthermore, the tyrosine kinase inhibitor genestein, the
PI-3 kinase
inhibitor wortmannin and phosphatase inhibition were without effects. In conclusion, the data suggest that NaF-induced increase of IL-8 in A549 cells involved PKC- and p38-linked pathways, whereas an ERK-dependent pathway counteracted the response. Tyrosine kinases, Ca(2+)-linked pathways,
PI-3 kinase
,
PKA
and phosphatase inhibition seem to play no or minor roles in the fluoride-induced IL-8 response.
...
PMID:Mechanisms in fluoride-induced interleukin-8 synthesis in human lung epithelial cells. 1156 78
The control of natural cell death is mediated by neurotrophins released by target, afferent and glial cells. In the present work we show that treatment of retinal cells 'in vitro' for 48 h with 25 microM carbamylcholine induced a two-fold increase in retinal ganglion cells survival. This effect was dose-dependent and mediated by M1 receptors since it could be blocked by 1 microM telenzepine (a M1 receptor antagonist) and mimicked by 200 microM oxotremorine (a M1 receptor agonist). The effect of carbamylcholine was abolished by 10 microM BAPTA-AM (an intracellular Ca2+ chelator), 30 microM dantrolene (an inhibitor of ryanodinic receptors), 500 nM H-89 (an inhibitor of
PKA
), 1.25 microM chelerythrine chloride (an inhibitor of PKC) and 50 microM PD-98059 (a MEK inhibitor). Treatment with 10 microM genistein (an inhibitor of tyrosine kinase), 25 microM LY-294002 (a
PI-3 kinase
blocker), 30 nM brefeldin-A (a blocker of polypeptides release), 50 nM K-252a (a Trk receptor inhibitor) and 20 microM fluorodeoxyuridine (an inhibitor of cell proliferation) totally inhibited the effect of carbamylcholine. Taken together our results indicate that muscarinic activity controls the survival of retinal ganglion cells through a mechanism involving the release of polypeptides and activation of Irk receptors.
...
PMID:Cholinergic activity modulates the survival of retinal ganglion cells in culture: the role of M1 muscarinic receptors. 1160 Mar 18
Mitogen-activated protein kinase and Phosphatidylinositol-3 kinase/Akt-mediated signaling pathways play a major role in controlling cell proliferation, differentiation and cell death. Phosphorylation and dephosphorylation of their specific Thr/Tyr residues is critical in determining their activity. We determined the expression pattern and activity of MAP kinases and Akt in Primitive Neuroectodermal Tumors (PNETs). The kinase activity of extracellular signal-regulated kinase (ERK) was higher in both primary tumors and cell lines, as evident from the increased phosphorylation of ERK1 and ERK2. We did not observe the activation of C-jun N-terminal kinase (JNK) or p38 MAPK The expression of
Raf-1
, a kinase acting upstream of ERK, was significantly increased in primary tumors compared to normal brain. The
PI-3 kinase
-activated phosphorylation of Akt was also higher in primary tumors. These results suggest that activation of the
Raf-1
/ERK module of the MAP kinase pathway play an important role in PNETs.
...
PMID:Role of MAP kinase pathways in primitive neuroectodermal tumors. 1172 48
Neurons in vivo are exposed to a variety of different growth factors and cytokines. A principal signalling pathway for ciliary neurotrophic factor (CNTF)-like cytokines is the Janus kinase (Jak)/signal transducer and activator of transcription (STAT) system of kinases and transcription factors. In the human cell line (SH-SY5Y), STAT1 and STAT3 activation by CNTF-like cytokines showed tyrosine phosphorylation peaking at 0.5 h and inactivating within 2 h. Tyrosine phosphorylation of the receptor-associated tyrosine kinases Jak1 and Jak2 showed a similar time course of activation and inactivation in response to CNTF. The STAT1 response to the non-CNTF-like cytokine, interferon-gamma (IFN-gamma) did not inactivate. Inactivation to CNTF was not due to a decrease in CNTF receptor subunit gp130 or in levels of Jak1 or Jak2. STAT inactivation was inhibited by the
protein kinase
blocker H7 and a tyrosine phosphatase blocker, but not by inhibitors of protein kinase C, mitogen-activated protein kinase (MAPK) kinase, mTOR-P70/S6 kinase or phosphatidyl inositol-3-kinase (
PI-3 kinase
). Surprisingly, CNTF caused only a minor increase in levels of suppressors of cytokine signalling, SOCS-1 and SOCS-3. CNTF pretreatment desensitized the cells to the CNTF-like cytokines, leukemia inhibitory factor and oncostatin-M but not to IFN-gamma. These results reveal a complex level of regulation of shared signalling pathways for cytokines that is dependent on both the type of cell and cytokine.
...
PMID:Activation and inactivation of signal transducers and activators of transcription by ciliary neurotrophic factor in neuroblastoma cells. 1188 86
Urocortin (Ucn), is a peptide related to hypothalamic corticotrophin-releasing factor (CRF) and binds with a high affinity to the CRF-R2 beta receptor which is expressed in the heart. Ucn promotes cardiac myocyte survival against hypoxia reoxygenation (HR) injury and this involves activation of the mitogen activated
protein kinase
pathway (MEK1/2 p42/44 MAPK). In this study we report that Ucn stimulates the phosphorylation of protein kinase B (PKB/Akt) via phosphatidylinositol (PI) 3-OH kinase (
PI-3 kinase
). To investigate the signalling pathways that mediate the anti-apoptotic and cell survival effect of Ucn in hypoxia reoxygenation (HR), gene based inhibitors of MEK1/2,
PI-3 kinase
and Akt were over-expressed in rat neonatal cardiac myocytes and cell survival effects against HR were assessed. The dominant negative mutants of the MEK1/2,
PI-3 kinase
and Akt inhibited Ucn mediated cardioprotection in HR and active
PI-3 kinase
was itself cardioprotective. In addition, chemical inhibitors of the
PI-3 kinase
pathway, wortmannin and LY294002 inhibit Ucn mediated cardioprotection in HR in both neonatal and adult cardiac myocytes. Hence the
PI-3 kinase
/Akt pathway is required in addition to MEK1/2 to mediate Ucn cardioprotection in HR. To our knowledge this is the first report of the activation of the
PI-3 kinase
/Akt pathway by a member of the CRF family of peptides.
...
PMID:Activation of protein kinase B/Akt by urocortin is essential for its ability to protect cardiac cells against hypoxia/reoxygenation-induced cell death. 1199 36
Patients with the autosomal recessive disorder ataxia telangiectasia (A-T) show the biallelic inactivation of the ataxia telangiectasia mutated (ATM) gene. A-T patients exhibit a predisposition to the development of a wide range of lymphoid tumours, suggesting that the ATM protein normally plays an important role in the prevention of both T and B cell malignancies. The ATM protein is a 370 kDa
protein kinase
implicated in the integration of different cellular responses to particular forms of DNA damage. Several recent studies have reported the possibility that the ATM gene can act as a tumour suppressor gene in non A-T individuals. Frequent ATM inactivation was confirmed in three sporadic lymphoid tumours of mature phenotype: T cell prolymphocytic leukaemia (T-PLL), B-cell chronic lymphocytic leukaemia (B-CLL) and mantle cell lymphoma (MCL). Here, we provide a summary of the published ATM mutations in sporadic lymphoid tumours, including our own study on the role of ATM mutations in the pathogenesis of sporadic B-CLL. The published results suggest possible differences in the origin, the nature and distribution of ATM mutations between sporadic B-CLL, MCL and T-PLL. While ATM mutations in mature B cell tumours (B-CLL and MCL) represent a mixture of missense and truncating errors distributed across the whole of the ATM coding sequence, mutations in sporadic T-PLL appear to be predominantly missense, clustering in the region encoding the
PI-3 kinase
catalytic domain of the protein. The reason for this difference is unclear, but the difference itself supports the notion that the pathogenesis of B and T cell tumours on an ATM deficient background might be different. In addition, in both B-CLL and MCL ATM mutation carriers have been reported, raising the possibility that ATM mutation carriers may have an increased risk of developing these tumours. The existence as well as magnitude of the risk, however, remains to be established. Furthermore, our own studies indicate that the presence of ATM mutations in sporadic B-CLL causes a distinctive defect in response to DNA damaging agents, offering a possible explanation for the poor response of ATM mutant tumours to standard treatment. Therefore, one of the future challenges will be to devise strategies to bypass the existing defect in response to DNA damage and activate apoptosis in ATM mutant sporadic lymphoid tumours.
...
PMID:ATM mutations in sporadic lymphoid tumours. 1240 May 98
The regulation of amphiregulin, an epidermal growth factor (EGF) family member, and its effect on vascular smooth muscle cells (VSMC) were examined. Amphiregulin mRNA was upregulated by amphiregulin itself as well as alpha-thrombin. Amphiregulin caused an approximate 3-fold increase in DNA synthesis. Its effect on growth was compared with those of other mitogens, and was found to be approximately 3.5-, 2.4-, and 1.0-fold greater than those of endothelin-I (ET-I), alpha-thrombin, and platelet-derived growth factor-AB (PDGF-AB), respectively. As evidenced by Western blot analysis, amphiregulin stimulated the phosphorylation of p42/p44-mitogen-activated protein kinase (MAPK), p38-MAPK, c-Jun NH2-terminal
protein kinase
(JNK), and Akt/protein kinase B (PKB), respectively. By statistical analysis, the amphiregulin-induced growth effect was significantly decreased by the MAP kinase/ extracellular regulated kinase kinase-1 (MEK-1) inhibitor PD98059, p38-MAPK inhibitor SB203580, and phosphatidylinositol 3-kinase (
PI-3 kinase
) inhibitor wortmannin, respectively, but was not decreased by JNK inhibitor SP600125. These results suggest that amphiregulin is the most potent mitogen of the mitogens tested, and its growth effect is mediated at least in part through the p42/p44-MAPK, p38-MAPK, and
PI-3 kinase
-Akt/PKB pathways in VSMC.
...
PMID:Amphiregulin is a potent mitogen for the vascular smooth muscle cell line, A7r5. 1258 27
We investigated the mechanistic role of Src and Ras, important oncoproteins implicated in the pathogenesis of many human cancers, in taxane-induced apoptosis using v-src or c-H-ras transfected HAG-1 human gallbladder epithelial cells. Compared with the parental HAG-1 cell line, v-src-transfected HAG/src3-1 cells became 6.0-fold and 7.5-fold sensitive to taxotere, and 1.8-fold and 3.9-fold sensitive to taxol, for 2-hour and 24-hour exposures, respectively. By contrast, HAG-1 cells transfected with activated Ras, which acts downstream of Src, acquired approximately 2.7- and 5.0-fold taxotere resistance, and 2.3- and 2.8-fold taxol resistance, for both exposures, respectively. To examine the mechanism(s) whereby Src augments sensitivity to taxanes, we investigated the functional role of Src in taxotere-induced apoptosis. Treatment of HAG/src3-1 cells with taxotere resulted in subsequent induction of apoptotic cell death, whereas apoptosis did not occur in parental or c-H-ras-transfected HAG/ras5-1 cells. Moreover, a protein kinase C (PKC) and a phosphatidylinositol-3 kinase (
PI-3 kinase
) inhibitors (H-7 and wortmannin, respectively) did not alter either taxotere sensitivity or taxotere-induced apoptosis in these cells. Similarly, non-cytotoxic concentrations of geldanamycin, which destabilizes c-Raf-1 kinase, did not prevent apoptosis in HAG/src3-1 cells. These data indicate that the ability of activated Src to sensitize HAG/src3-1 cells to taxotere might be mediated by apoptotic events occurring through Src to downstream signal transduction pathways, excluding activated Ras,
Raf-1
kinase,
PI-3 kinase
and PKC.
...
PMID:Src tyrosine kinase but not activated Ras augments sensitivity to taxanes through apoptosis in human adenocarcinoma cells. 1268 Jan 88
Alzheimer's disease (AD) is characterised by deposition of a 4 kDa amyloid-beta peptide (Abeta) into senile plaques of the affected brain. Abeta is a proteolytic product of the membrane protein, amyloid precursor protein (APP). An alternative cleavage pathway involves alpha-secretase activity and results in secretion of a 100 kDa non-amyloidogenic APP (sAPPalpha) and therefore a potential reduction in Abeta secretion. We have shown that estrogen induces alpha-cleavage and therefore results in the secretion of sAPPalpha. This secretion is signalled via MAP-kinase and
PI-3 kinase
signal-transduction pathways. These pathways also have the potential to inhibit the activation of
glycogen synthase kinase
3beta (GSK), a protein involved in cell death. Therefore, the aim of this work was to further elucidate the estrogen-mediated signaling pathways involved in APP processing, with particular emphasis on GSK activity. By stimulating rat hypothalamic neuronal GT1-7 cells with estradiol, we found that estrogen decreases the activation state of GSK via the MAP kinase pathway. Moreover, the inhibition of GSK activity by LiCl causes enhanced sAPPalpha secretion in a pattern similar to that seen in response to estrogen, suggesting a pivotal role for this deactivation in APP processing. Further, inactivation of GSK by estrogen can be confirmed in an in vivo model. Elucidation of the signaling pathways involved in APP processing may help to understand the pathology of AD and may also prove beneficial in developing therapeutic strategies to combat AD.
...
PMID:Estrogen-induced cell signalling in a cellular model of Alzheimer's disease. 1271 Oct 16
A431 epidermoid carcinoma cells have an increased expression of EGF receptor. In contrast to many other cell lines and primary cells, these respond to EGF in high (more than 1 ng/ml) concentrations by cell cycle arrest, apoptosis and detachment. Clonal variants of A431 (1a and 8a), able to grow in the presence of EGF in high concentration, were previously developed in our laboratory (Gudkova, Sorokin, 1989). Here we tested upper pathways of signal transduction from EGF receptor in the clonal variants, as compared to A431. We found no reasonable difference in the expression of EGF receptor, as well as in its EGF-induced phosphorylation in A431 and clonal variants. There were also no changes in the amount and activation of ERK MAP kinase in different cell lines. In contrast, the amount of STAT1 transcription factor, known to play pro-apoptotic and antiproliferative roles, was strictly diminished in both the clonal variants tested (1a and 8a), as compared to the parental line A431. However, EGF-induced tyrosine phosphorylation of STAT1 decreased only in 8a. Increased phosphorylation of Akt
protein kinase
, the key component of
PI-3 kinase
of the anti-apoptotic and proliferative signaling pathway, was also observed in clonal variants. The data obtained demonstrate that resistance to EGF can be acquired in cells having similar levels of EGF receptor expression and phosphorylation, but different in STAT1 or
PI-3 kinase
signal transduction pathways. These pathways may presumably represent two antagonistic key elements regulating A431 proliferation and apoptosis.
...
PMID:[EGF-induced signal transduction in clonal cells of epidermoid carcinoma A431]. 1272 80
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