Stimulation of ERK2 by taurine with enhanced alkaline phosphatase activity and collagen synthesis in osteoblast-like UMR-106 cells11Abbreviations: ERK, extracellular signal regulated protein kinase; MAP, mitogen-activated protein; MEK, MAP kinase kinase; and MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

2001 ◽  
Vol 62 (8) ◽  
pp. 1107-1111 ◽  
Author(s):  
Sungyoun Park ◽  
Harriet Kim ◽  
Sung-Jin Kim
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Kinase ◽  
Alkaline Phosphatase Activity ◽  
Collagen Synthesis ◽  
Extracellular Signal ◽  
Diphenyltetrazolium Bromide ◽  
Mitogen Activated Protein ◽  
Umr 106 ◽  
Map Kinase Kinase ◽  
Stimulation Of

scholarly journals Activation of the Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Pathway by Conventional, Novel, and Atypical Protein Kinase C Isotypes

1998 ◽  
Vol 18 (2) ◽  
pp. 790-798 ◽  
Author(s):  
Dorothee C. Schönwasser ◽  
Richard M. Marais ◽  
Christopher J. Marshall ◽  
Peter J. Parker
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Mapk ◽  
Kinase C ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Stimulation Of

ABSTRACT Phorbol ester treatment of quiescent Swiss 3T3 cells leads to cell proliferation, a response thought to be mediated by protein kinase C (PKC), the major cellular receptor for this class of agents. We demonstrate here that this proliferation is dependent on the activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade. It is shown that dominant-negative PKC-α inhibits stimulation of the ERK/MAPK pathway by phorbol esters in Cos-7 cells, demonstrating a role for PKC in this activation. To assess the potential specificity of PKC isotypes mediating this process, constitutively active mutants of six PKC isotypes (α, β1, δ, ɛ, η, and ζ) were employed. Transient transfection of these PKC mutants into Cos-7 cells showed that members of all three groups of PKC (conventional, novel, and atypical) are able to activate p42 MAPK as well as its immediate upstream activator, the MAPK/ERK kinase MEK-1. At the level of Raf, the kinase that phosphorylates MEK-1, the activation cascade diverges; while conventional and novel PKCs (isotypes α and η) are potent activators of c-Raf1, atypical PKC-ζ cannot increase c-Raf1 activity, stimulating MEK by an independent mechanism. Stimulation of c-Raf1 by PKC-α and PKC-η was abrogated for RafCAAX, which is a membrane-localized, partially active form of c-Raf1. We further established that activation of Raf is independent of phosphorylation at serine residues 259 and 499. In addition to activation, we describe a novel Raf desensitization induced by PKC-α, which acts to prevent further Raf stimulation by growth factors. The results thus demonstrate a necessary role for PKC and p42 MAPK activation in 12-O-tetradecanoylphorbol-13-acetate induced mitogenesis and provide evidence for multiple PKC controls acting on this MAPK cascade.

Activation of p44/p42 Mitogen-Activated Protein Kinase Limits Triiodothyronine-Stimulated Alkaline Phosphatase Activity in Osteoblasts

2001 ◽  
Vol 286 (5) ◽  
pp. 1140-1143 ◽  
Author(s):  
Osamu Kozawa ◽  
Daijiro Hatakeyama ◽  
Minoru Yoshida ◽  
Yasuka Kamiya ◽  
Chihiro Kondo ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Kinase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

α1-AR-mediated activation of NKCC in rat cardiomyocytes involves ERK-dependent phosphorylation of the cotransporter

2004 ◽  
Vol 286 (4) ◽  
pp. H1354-H1360 ◽  
Author(s):  
Geir Øystein Andersen ◽  
Tor Skomedal ◽  
Mette Enger ◽  
Astrid Fidjeland ◽  
Trond Brattelid ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Hormonal Regulation ◽  
Isolated Rat Heart ◽  
Rat Cardiomyocytes ◽  
Extracellular Signal ◽  
Rat Hearts ◽  
Mitogen Activated Protein ◽  
Perfused Rat Hearts ◽  
Isolated Rat ◽  
Stimulation Of

We studied molecular and functional characteristics as well as hormonal regulation of the Na-K-2Cl cotransporter (NKCC) in the isolated rat heart and cardiomyocytes. NKCC activity was measured as bumetanide-sensitive 86Rb+ influx in isolated perfused rat hearts and isolated cardiomyocytes. Stimulation of α1-adrenoceptors (AR) by phenylephrine (30 μM) increased 86Rb+ influx. The NKCC inhibitor bumetanide (50 μM) reduced the response to phenylephrine by 45 ± 13% ( n = 12, P < 0.01). PD-98059 (10 μM), an inhibitor of the activation of the mitogen-activated protein kinases extracellular signal-regulated protein kinase 1 and 2 (ERK1/2), reduced the total response to phenylephrine by 51 ± 13% ( n = 10, P < 0.01) and eliminated the bumetanide-sensitive component, indicating that α1-AR mediated stimulation of NKCC is dependent on activation of ERK1/2. Inhibitors of protein kinase C or phosphatidylinositol 3-kinase had no effect. The presence of NKCC mRNA and protein was demonstrated in isolated rat cardiomyocytes. Phosphorylation of NKCC after α1-AR stimulation was shown by immunoprecipitation of the phosphoprotein from 32Pi prelabeled cardiomyocytes. Increased phosphorylation of the NKCC protein was also abolished by PD-98059. We conclude that the NKCC is present in rat cardiomyocytes and that ion transport by the cotransporter is regulated by α1-AR stimulation through phosphorylation of this protein involving the ERK pathway.

scholarly journals Role of phosphoinositide 3-kinase and the Cbl adaptor protein in coupling the α4β1 integrin to mitogen-activated protein kinase signalling

2000 ◽  
Vol 345 (2) ◽  
pp. 385-392 ◽  
Author(s):  
Lisa D. FINKELSTEIN ◽  
Yoji SHIMIZU
Keyword(s):  
Protein Kinase ◽  
Adaptor Protein ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Hl60 Cells ◽  
Intracellular Signals ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Phosphoinositide 3 Kinase ◽  
Stimulation Of

Cell adhesion mediated by β1 integrin receptors leads to the initiation of intracellular signals that affect cell differentiation and survival. Here we have analysed the mechanism by which the α4β1 integrin activates the mitogen-activated protein kinase pathway in HL60 cells, a myelomonocytic cell line that lacks the expression of focal adhesion kinase. A role for phosphoinositide 3-kinase (PI-3K) in α4 integrin-mediated activation of extracellular signal-regulated protein kinase 2 (ERK2) is suggested by the ability of PI-3K inhibitors and a dominant-negative form of the p85 subunit of PI-3K to block the activation of ERK2 by integrin. Stimulation of α4β1 integrins on HL60 cells also leads to increased tyrosine phosphorylation of the 120 kDa adaptor protein Cbl. PI-3K activity associated with Cbl also increases on the stimulation of α4β1 integrins, although immunodepletion experiments suggest that Cbl-associated PI-3K does not account for all of the PI-3K activity induced on the stimulation of integrins in these cells. The expression of wild-type Cbl or the 70Z/3 Cbl mutant enhances basal ERK2 activity in transfectants with a minimal effect on α4 integrin-mediated ERK2 activity. In contrast, overexpression of the Hut Cbl truncation mutant, which does not associate with p85, has no effect on the ERK2 pathway. These results suggest that PI-3K has a major role in coupling α4β1 integrins to ERK2 activation in myeloid cells and that the Cbl adaptor protein has a role in basal, but not α4β1 integrin-mediated, activation of ERK2.

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