Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of PC12 pheochromocytoma cells with nerve growth factor (NGF) or bradykinin leads to the activation of extracellular signal-regulated kinases ERK1 and ERK2, two isozymes of microtubule-associated protein 2 (MAP) kinase that are present in numerous cell lines and regulated by diverse extracellular signals. The activation of MAP kinase is associated with its phosphorylation on tyrosine and threonine residues, both of which are required for activity. In the present studies, we have identified a factor in extracts of PC12 cells treated with NGF or bradykinin, named MAP kinase activator, that, when reconstituted with inactive MAP kinase from untreated cells, dramatically increased MAP kinase activity. Activation of MAP kinase in vitro by this factor required MgATP and was associated with the phosphorylation of a 42- (ERK1) and 44-kDa (ERK2) polypeptide. Incorporation of 32P into ERK1 and ERK2 occurred primarily on tyrosine and threonine residues and was associated with a single tryptic peptide, which is identical to one whose phosphorylation is increased by treatment of intact PC12 cells with NGF. Thus, the MAP kinase activator identified in PC12 cells is likely to be a physiologically important intermediate in the signaling pathways activated by NGF and bradykinin. Moreover, stimulation of the activator by NGF and bradykinin suggests that tyrosine kinase receptors and guanine nucleotide-binding protein-coupled receptors are both capable of regulating these pathways.
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PMID:Identification of an activator of the microtubule-associated protein 2 kinases ERK1 and ERK2 in PC12 cells stimulated with nerve growth factor or bradykinin. 131 64

Tyrosine hydroxylase (TH) is phosphorylated at four sites in situ and in vivo, and the protein kinases that phosphorylate three of these sites (Ser8,Ser19,Ser40) have been identified. In intact cells, the phosphorylation of the fourth site (Ser31) is increased in response to phorbol esters or nerve growth factor (NGF). Here, we show that Ser31 is phosphorylated by ERK1 and ERK2, two myelin basic protein and microtubule-associated protein kinases. Extracts of NGF- or bradykinin-treated PC12 rat pheochromocytoma cells were fractionated on Mono Q columns. Protein kinase activity toward Ser31 in TH was present in two peaks corresponding to myelin basic protein kinase activities previously identified as ERK1 and ERK2. Phosphorylation of purified TH in vitro by both kinases was selective for Ser31 up to at least 0.6 mol of phosphate per mol of TH subunit. Treatment of intact PC12 cells with bradykinin or NGF increased both the phosphorylation of TH-Ser31 in situ and the catalytic activity of ERKs (measured subsequently in vitro with myelin basic protein as substrate). Pretreatment of the cells with genistein (a protein-tyrosine kinase inhibitor) decreased the bradykinin- but not the NGF-induced changes in both TH-Ser31 phosphorylation and ERK activity. Genistein also inhibited the increases in Ser31 phosphorylation produced by phorbol dibutyrate, muscarine, and Ba2+. The data indicate that ERK activity is responsible for phosphorylating TH at Ser31 in intact cells and suggest that TH-Ser31 phosphorylation may be regulated by multiple signaling pathways that converge at or prior to the activation of the ERKs.
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PMID:ERK1 and ERK2, two microtubule-associated protein 2 kinases, mediate the phosphorylation of tyrosine hydroxylase at serine-31 in situ. 134 49

Addition of gastrin releasing peptide to serum-starved Swiss 3T3 mouse fibroblasts results in a transient appearance of a myelin basic protein-kinase activity in cytosolic extracts. Increased kinase activity is also observed upon stimulation of cells with bradykinin, epidermal growth factor or 4 beta-phorbol dibutyrate. Chromatographic analysis of the cytosolic extracts show that both gastrin-releasing peptide and 4 beta-phorbol dibutyrate induce the appearance of a kinase activity similar to that induced by epidermal growth factor. The response to gastrin-releasing peptide is abolished by down-regulation of protein kinase C and attenuated by acute inhibition of protein kinase C using staurosporine. The effect of epidermal growth factor was also suppressed under these conditions, albeit to a lesser extent. The results indicate (1) that activation of myelin basic protein kinase(s) may be common to different growth factors, and (2) that protein kinase C may participate in this response, at least in the case of gastrin-releasing peptide.
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PMID:Protein kinase C-dependent activation of a myelin basic protein kinase by gastrin-releasing peptide in Swiss 3T3 fibroblasts. 193 82

The effect of alkylglycerol supplementation on protein kinase C (PKC)-mediated signaling events has been studied in fibroblasts from Zellweger patients (SF 3271 cells). Western blotting analysis established that Zellweger fibroblasts express PKC alpha, epsilon, and zeta. Incubation with bradykinin induced a rapid transient translocation of PKC alpha and a more sustained translocation of PKC epsilon to the particulate fraction; translocation of PKC zeta was unaffected. Bradykinin-induced translocation and activation of PKC alpha, but not translocation of PKC epsilon, was blocked in SF 3271 cells which had been incubated with 1-O-hexadecylglycerol (1-O-HDG; 20 micrograms/ml) for 24 h and then incubated in the absence of 1-O-HDG and serum for a further 24 h. Supplementation with 1-O-HDG increased the mass of ether-linked phospholipid. Bradykinin initiated a transient increase in cytosolic Ca2+ concentration in both control and 1-O-HDG supplemented cells, indicating that the initial receptor linked events were not affected by 1-O-HDG supplementation. Bradykinin also caused a rapid activation of phospholipase D (PLD), measured by phosphatidylbutanol accumulation, and mitogen-activated protein kinase (MAPK) determined by myelin basic protein phosphorylation of Mono Q fractions. Both events were blocked by preincubation of the cells with 12-O-tetradecanoylphorbol-13-acetate for 24 h to deplete PKC protein. 1-O-HDG supplementation prevented the bradykinin-induced activation of PLD, but had no effect on the stimulation of MAPK activity. These results establish that modulation of the ether lipid composition of membranes can alter PKC isozyme translocation and indicate that a PKC isozyme other than PKC alpha, most likely PKC epsilon, is involved in MAPK activation.
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PMID:Evidence that the bradykinin-induced activation of phospholipase D and of the mitogen-activated protein kinase cascade involve different protein kinase C isoforms. 753 66

The activation of endothelial cells following exposure to a variety of receptor-dependent and -independent stimuli is associated with the release of Ca2+ from intracellular stores as well as the influx of Ca2+ from the extracellular space. In the present study, we investigated the interaction between Ca2+ signaling in cultured human umbilical vein endothelial cells and tyrosine phosphorylation. Stimulation of endothelial cells with either bradykinin (100 nmol/L), histamine (1 mumol/L), or the Ca(2+)-ATPase inhibitor thapsigargin (30 nmol/L) resulted in a slightly delayed but prolonged tyrosine phosphorylation of two low molecular weight proteins (approximately 42 and approximately 44 kD). These proteins were identified by immunoprecipitation as the 42- and 44-kD isoforms of mitogen-activated protein kinase (MAP kinase). The agonist-induced tyrosine phosphorylation of the 42-/44-kD doublet was sensitive to the tyrosine kinase inhibitors genistein (100 mumol/L) and piceatannol (10 mumol/L) and was inhibited by the removal of Ca2+ from the extracellular medium. In fura 2-loaded endothelial cells, inhibition of tyrosine kinases attenuated Ca2+ signaling after stimulation with either bradykinin (30 nmol/L) or thapsigargin (30 nmol/L). Since inhibition of tyrosine kinases specifically attenuates the plateau phase of the Ca2+ response after stimulation, the effect of tyrosine kinase inhibition appeared to be mostly associated with the influx of Ca2+ from the extracellular space.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Calcium signaling in endothelial cells involves activation of tyrosine kinases and leads to activation of mitogen-activated protein kinases. 789 28

Endothelins (ET-1, -2, -3) display pleiotropic activities, by signalling through G-protein-coupled membrane receptors. We show here that ET-1 and ET-3 stimulate within minutes the tyrosine phosphorylation of a 42 kDa protein (p42) in primary cultures of mouse embryo astrocytes, but not in any of two subclones of rat astrocytoma C6 cells. This effect, measured by anti-phosphotyrosine immunoblotting of cell extracts, was also observed in response to bradykinin, platelet-derived growth factor, the phorbol ester phorbol 12-myristate 13-acetate and the G-protein activator fluoroaluminate. Pretreatment of cells with pertussis toxin, which inactivates Gi/G(o) proteins, did not affect these responses. However, down-regulation of protein kinase C completely blocked the response to phorbol ester and fluoroaluminate and at least partially impaired the ET-1-stimulated phosphorylation of p42. We have identified p42 as p42mapk, a mitogen-activated protein (MAP) kinase, on the basis of the following data: by sequential immunoblotting with antiphosphotyrosine and anti-MAP kinase antibodies, (i) similar kinetics are observed for p42 phosphorylation and the decrease in p42mapk electrophoretic mobility, likely corresponding to its tyrosine/threonine phosphorylation [de Vries-Smits, Boudewijn, Burgering, Leevers, Marshall and Bos (1992) Nature (London) 357, 602-604]; (ii) p42 and the shifted form of p42mapk co-migrate on SDS/PAGE; (iii) the myelin-basic-protein kinase activity of p42mapk is stimulated by ET-1, in parallel with the tyrosine phosphorylation of p42. In conclusion, these findings strongly suggest that endothelins can stimulate the tyrosine phosphorylation and activation of p42mapk in astrocytes, via pertussis-toxin-insensitive G protein and protein kinase C-dependent and -independent pathways.
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PMID:Endothelins stimulate tyrosine phosphorylation and activity of p42/mitogen-activated protein kinase in astrocytes. 834 18

The endothelial response to kinin stimulation is the result of a series of complex intracellular reactions involving changes in the intracellular concentration of free calcium ([Ca2+]i) and intracellular pH, enhanced phosphorylation of several proteins via the activation of at least four distinct families of protein kinases, and activation of membrane ion transport systems. Some of the more recent developments in this field suggest that endothelial tyrosine kinases and tyrosine phosphatases as well as serine/threonine phosphatases are also activated in response to bradykinin. In addition, the finding that the mitogen-activated protein kinase (MAP kinase) pathway was tyrosine phosphorylated, and presumably activated, in endothelial cells after an increase in [Ca2+]i has wideranging implications for these cells. Indeed, MAP kinase recognizes many different substrates in the cell, including growth factor receptors, microtubule-associated proteins, specific serine-threonine protein kinases, phospholipase A2, and transcription factors. Further recent studies of interest have underscored the role of endothelium-derived hyperpolarizing factor in addition to nitric oxide and prostacyclin in the coronary vasculature. Indeed, this mediator, which seems to be an endothelium-derived, cytochrome P450-derived metabolite of arachidonic acid, would now appear to represent a substantial constitutive component of the vasodilator response to bradykinin.
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PMID:Molecular responses of endothelial tissue to kinins. 852 5

1. In cultures of bovine tracheal smooth muscle cells, platelet-derived growth factor-BB (PDGF), bradykinin (BK) and endothelin-1 (ET-1) stimulated the tyrosine phosphorylation and activation of both pp42 and pp44 kDa forms of mitogen-activated protein (MAP) kinase. 2. Both ET-1 and PDGF stimulated a sustained activation of MAP kinase whilst the response to BK was transient. 3. Activation of MAP kinase occurred in a concentration-dependent manner (EC50 values: ET-1, 2.3 +/- 1.3 nM; BK, 8.7 +/- 4.1 nM, PDGF, 9.7 +/- 3.2 ng ml-1). 4. Pretreatment with the protein kinase C (PKC) inhibitor Ro-318220, significantly reduced ET-1 activation of MAP kinase at 2 and 5 min but enhanced MAP kinase activation at 60 min. 5. Following chronic phorbol ester pretreatment, BK-stimulated activation of MAP kinase was abolished whilst the responses to PDGF and ET-1 were only partly reduced (80 and 45% inhibition respectively). 6. Pretreatment with pertussis toxin reduced ET-1 stimulated activation of MAP kinase particularly at later times (60 min), but left the responses to both PDGF and BK unaffected. 7. ET-1 also stimulated a 3 fold increase in [3H]-thymidine incorporation which was abolished by pertussis toxin pretreatment. In contrast, PDGF stimulated a 131 fold increase in [3H]-thymidine incorporation which was not affected by pertussis toxin. 8. These results suggest that a pertussis toxin-sensitive activation of MAP kinase may play an important role in ET-1-stimulated DNA synthesis but that activation of MAP kinase alone is not sufficient to induce the magnitude of DNA synthesis observed in response to PDGF.
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PMID:Stimulation by endothelin-1 of mitogen-activated protein kinases and DNA synthesis in bovine tracheal smooth muscle cells. 856 58

In ventricular myocytes cultured from neonatal rat hearts, bradykinin (BK), kallidin or BK(1-8) [(Des-Arg9)BK] stimulated PtdinsP2 hydrolysis by 3-4-fold. EC50 values were 6 nM (BK), 2 nM (kallidin), and 14 microM [BK(1-8)]. BK or kallidin stimulated the rapid (less than 30 s) translocation of more than 80% of the novel protein kinase C (PKC) isoforms nPKC-delta and nPKC-epsilon from the soluble to the particulate fraction. EC50 values for nPKC-delta translocation by BK or kallidin were 10 and 2 nM respectively. EC50 values for nPKC-epsilon translocation by BK or kallidin were 2 and 0.6 nM respectively. EC50 values for the translocation of nPKC-delta and nPKC-epsilon by BK(1-8) were more than 5 microM. The classical PKC, cPKC-alpha, and the atypical PKC, nPKC-zeta, did not translocate. BK caused activation and phosphorylation of p42-mitogen-activated protein kinase (MAPK) (maximal at 3-5 min, 30-35% of p42-MAPK phosphorylated). p44-MAPK was similarly activated. EC50 values for p42/p44-MAPK activation by BK were less than 1 nM whereas values for BK(1-8) were more than 10 microM. The order of potency [BK approximately equal to kallidin >> BK (1-8)] for the stimulation of PtdInsP2 hydrolysis, nPKC-delta and nPKC-epsilon translocation, and p42/p44-MAPK activities suggests involvement of the B2 BK receptor subtype. In addition, stimulation of all three processes by BK was inhibited by the B2BK receptor-selective antagonist HOE140 but not by the B1-selective antagonist Leu8BK(1-8). Exposure of cells to phorbol 12-myristate 13-acetate for 24 h inhibited subsequent activation of p42/p44-MAPK by BK suggesting participation of nPKC (and possibly cPKC) isoforms in the activation process. Thus, like hypertrophic agents such as endothelin-1 (ET-1) and phenylephrine (PE), BK activates PtdInsP2 hydrolysis, translocates nPKC-delta, and nPKC-epsilon, and activates p42/p44-MAPK. However, in comparison with ET-1 and PE, BK was only weakly hypertrophic as assessed by cell morphology and patterns of gene expression. This difference could not be attributed to dissimilarities between the duration of activation of p42/p44-MAPK by BK or ET-1. Thus activation of these signalling pathways alone may be insufficient to induce a powerful hypertrophic response.
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PMID:Stimulation of phosphatidylinositol hydrolysis, protein kinase C translocation, and mitogen-activated protein kinase activity by bradykinin in rat ventricular myocytes: dissociation from the hypertrophic response. 869 51

The mechanisms by which mitogenic G-protein-coupled receptors activate the MAP kinase signalling pathway are poorly understood. Candidate protein tyrosine kinases that link G-protein-coupled receptors with MAP kinase include Src family kinases, the epidermal growth factor receptor, Lyn and Syk. Here we show that lysophosphatidic acid (LPA) and bradykinin induce tyrosine phosphorylation of Pyk2 and complex formation between Pyk2 and activated Src. Moreover, tyrosine phosphorylation of Pyk2 leads to binding of the SH2 domain of Src to tyrosine 402 of Pyk2 and activation of Src. Transient overexpression of a dominant interfering mutant of Pyk2 or the protein tyrosine kinase Csk reduces LPA- or bradykinin-induced activation of MAP kinase. LPA- or bradykinin-induced MAP kinase activation was also inhibited by overexpression of dominant interfering mutants of Grb2 and Sos. We propose that Pyk2 acts with Src to link Gi- and Gq-coupled receptors with Grb2 and Sos to activate the MAP kinase signalling pathway in PC12 cells.
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PMID:A role for Pyk2 and Src in linking G-protein-coupled receptors with MAP kinase activation. 884 29


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