scholarly journals Mitogen-activated protein kinase activation is insufficient for growth factor receptor-mediated PC12 cell differentiation.

1995 ◽  
Vol 15 (7) ◽  
pp. 3644-3653 ◽  
Author(s):  
R R Vaillancourt ◽  
L E Heasley ◽  
J Zamarripa ◽  
B Storey ◽  
M Valius ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Growth Factor ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Pc12 Cell ◽  
Growth Factor Receptor ◽  
Receptor Activation ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Kinase Pathway

When expressed in PC12 cells, the platelet-derived growth factor beta receptor (beta PDGF-R) mediates cell differentiation. Mutational analysis of the beta PDGF-R indicated that persistent receptor stimulation of the Ras/Raf/mitogen-activated protein (MAP) kinase pathway alone was insufficient to sustain PC12 cell differentiation. PDGF receptor activation of signal pathways involving p60c-src or the persistent regulation of phospholipase C gamma was required for PC12 cell differentiation. beta PDGF-R regulation of phosphatidylinositol 3-kinase, the GTPase-activating protein of Ras, and the tyrosine phosphatase, Syp, was not required for PC12 cell differentiation. In contrast to overexpression of oncoproteins involved in regulating the MAP kinase pathway, growth factor receptor-mediated differentiation of PC12 cells requires the integration of other signals with the Ras/Raf/MAP kinase pathway.

scholarly journals Differential regulation of Raf-1 and B-Raf and Ras-dependent activation of mitogen-activated protein kinase by cyclic AMP in PC12 cells.

1995 ◽  
Vol 15 (10) ◽  
pp. 5524-5530 ◽  
Author(s):  
P Erhardt ◽  
J Troppmair ◽  
U R Rapp ◽  
G M Cooper
Keyword(s):  
Growth Factor ◽  
Cyclic Amp ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Kinase Pathway ◽  
Stimulation Of

Growth factor stimulation of the mitogen-activated protein (MAP) kinase pathway in fibroblasts is inhibited by cyclic AMP (cAMP) as a result of inhibition of Raf-1. In contrast, cAMP inhibits neither nerve growth factor-induced MAP kinase activation nor differentiation in PC12 pheochromocytoma cells. Instead, in PC12 cells cAMP activates MAP kinase. Since one of the major differences between the Ras/Raf/MAP kinase cascades of these cell types is the expression of B-Raf in PC12 cells, we compared the effects of cAMP on Raf-1 and B-Raf. In PC12 cells maintained in serum-containing medium, B-Raf was refractory to inhibition by cAMP, whereas Raf-1 was effectively inhibited. In contrast, both B-Raf and Raf-1 were inhibited by cAMP in serum-starved PC12 cells. The effect of cAMP is thus dependent upon growth conditions, with B-Raf being resistant to cAMP inhibition in the presence of serum. These results were extended by studies of Rat-1 fibroblasts into which B-Raf had been introduced by transfection. As in PC12 cells, B-Raf was resistant to inhibition by cAMP in the presence of serum, whereas Raf-1 was effectively inhibited. In addition, the expression of B-Raf rendered Rat-1 cells resistant to the inhibitory effects of cAMP on both growth factor-induced activation of MAP kinase and mitogenesis. These results indicate that Raf-1 and B-Raf are differentially sensitive to inhibition by cAMP and that B-Raf expression can contribute to cell type-specific differences in the regulation of the MAP kinase pathway. In contrast to the situation in PC12 cells, cAMP by itself did not stimulate MAP kinase in B-Raf-expressing Rat-1 cells. The activation of MAP kinase by cAMP in PC12 cells was inhibited by the expression of a dominant negative Ras mutant, indicating that cAMP acts on a target upstream of Ras. Thus, it appears that a signaling component upstream of Ras is also require for cAMP stimulation of MAP kinase in PC12 cells.

scholarly journals Phosphoprotein Enriched in Astrocytes 15 kDa (PEA-15) Reprograms Growth Factor Signaling by Inhibiting Threonine Phosphorylation of Fibroblast Receptor Substrate 2α

2010 ◽  
Vol 21 (4) ◽  
pp. 664-673 ◽  
Author(s):  
Jacob R. Haling ◽  
Fen Wang ◽  
Mark H. Ginsberg
Keyword(s):  
Growth Factor ◽  
Map Kinase ◽  
Tyrosine Phosphorylation ◽  
Growth Factor Receptor ◽  
Receptor Activation ◽  
Growth Factor Signaling ◽  
Fgf Receptor ◽  
Cellular Expression ◽  
Map Kinase Pathway ◽  
Kinase Pathway

Changes in cellular expression of phosphoprotein enriched in astrocytes of 15 kDa (PEA-15) are linked to insulin resistance, tumor cell invasion, and cellular senescence; these changes alter the activation of the extracellular signal-regulated kinase (ERK)1/2 mitogen-activated protein (MAP) kinase pathway. Here, we define the mechanism whereby increased PEA-15 expression promotes and sustains ERK1/2 activation. PEA-15 binding prevented ERK1/2 membrane recruitment and threonine phosphorylation of fibroblast receptor substrate 2α (FRS2α), a key link in fibroblast growth factor (FGF) receptor activation of ERK1/2. This reduced threonine phosphorylation led to increased FGF-induced tyrosine phosphorylation of FRS2α, thereby enhancing downstream signaling. Conversely, short hairpin RNA-mediated depletion of endogenous PEA-15 led to reduced FRS2α tyrosine phosphorylation. Thus, PEA-15 interrupts a negative feedback loop that terminates growth factor receptor signaling downstream of FRS2α. This is the dominant mechanism by which PEA-15 activates ERK1/2 because genetic deletion of FRS2α blocked the capacity of PEA-15 to activate the MAP kinase pathway. Thus, PEA-15 prevents ERK1/2 localization to the plasma membrane, thereby inhibiting ERK1/2-dependent threonine phosphorylation of FRS2α to promote activation of the ERK1/2 MAP kinase pathway.

Dibucaine and Tetracaine Inhibit the Activation of Mitogen-activated Protein Kinase Mediated by L-type Calcium Channels in PC12 Cells 

1999 ◽  
Vol 91 (6) ◽  
pp. 1798-1798 ◽  
Author(s):  
Masumi Kansha ◽  
Taro Nagata ◽  
Kazuo Irita ◽  
Shosuke Takahashi
Keyword(s):  
Map Kinase ◽  
Pc12 Cells ◽  
Local Anesthetics ◽  
Mitogen Activated Protein ◽  
Ic50 Values ◽  
Map Kinase Pathway ◽  
Kinase Signaling Pathway ◽  
Kinase Pathway ◽  
Map Kinase Signaling Pathway ◽  
Ca2 Channels

Background An elevation of the intracellular calcium level, which is mediated by N-methyl-D-aspartate receptors and L-type Ca2+ channels both, activates the mitogen-activated protein (MAP) kinase signaling pathway involved in synaptic modification. It has recently been suggested that MAP kinase plays a role in coupling the synaptic excitation to gene expression in the nucleus of postsynaptic neurons. Because the effects of local anesthetics on cellular signal transduction in neuronal cells are not well-known, the authors investigated whether they affect the MAP kinase signaling pathway using PC12 cells. Methods The cells were stimulated with either 50 mM KCl or 1 microM ionomycin, and activated MAP kinase was thus immunoprecipitated. The immunocomplexes were then subjected to an Elk1 phosphorylation assay. Both the phosphorylation of MAP kinase and the induction of c-Fos were detected by immunoblotting. Results Pretreatment of the cells with 1 mM (ethylenedioxy)-diethyl-enedinitrilotetraacetic acid or 5 micron nifedipine blocked the MAP kinase activation induced by 50 mM KCl, whereas pretreatment with 2 microM omega-conotoxin GIVA did not. The expression of c-Fos induced by potassium chloride was also suppressed by dibucaine, tetracaine (concentrations that inhibited 50% of the activity of positive control [IC50s] were 16.2+/-0.2 and 73.2+/-0.7 microM, respectively), and PD 98059, a mitogen-activated/extracellular receptor-regulated kinase inhibitor. Higher concentrations of dibucaine and tetracaine were needed to suppress the activation of MAP kinase induced by ionomycin (the IC50 values of dibucaine and tetracaine were 62.5+/-2.2 and 330.5+/-32.8 microM, respectively) compared with potassium chloride (the IC50 values of dibucaine and tetracaine were 17.7+/-1.0 and 70.2+/-1.2 microM, respectively). Although probable targets of these local anesthetics might be L-type Ca2+ channels or components between Ca2+ and Ras in MAP kinase pathway, the possibility that they directly affect MAP kinase still remains. Conclusions Dibucaine and tetracaine at clinical concentrations were found to inhibit the activation of MAP kinase and the expression of c-Fos mediated by L-type Ca2+ channels in PC12 cells. The suppression of MAP kinase pathway may thus be a potential target site for the actions of dibucaine and tetracaine, including the modification of the synaptic functions.

scholarly journals Nitric Oxide Synthase Inhibitors Modulate Nerve-Growth-Factor Mediated Activation of Akt

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Cheryl L. Cragg ◽  
Janet C. MacKinnon ◽  
Bettina E. Kalisch
Keyword(s):  
Nitric Oxide ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Cell Lines ◽  
Nerve Growth ◽  
Akt Phosphorylation ◽  
Map Kinase Pathway ◽  
Kinase Pathway

Nitric oxide (NO) modulates nerve-growth-factor- (NGF-) mediated signaling and gene expression. In the present paper, the role of NO in NGF-mediated Akt activation in PC12 and IMR32 cells was investigated. Cells were treated with NGF (50 ng/mL) in the presence or absence of NO synthase (NOS) inhibitors and Akt phosphorylation assessed by western blot analysis. In both cell lines, Akt was phosphorylated within 15 min of NGF treatment. In PC12 cells, this level of phosphorylation was sustained for 60 min, while in IMR32 cells, the activation decreased after 30 min of NGF treatment. The nonselective NOS inhibitor Nω-nitro-L-arginine methylester (L-NAME; 20 mM) had no effect on NGF-mediated Akt phosphorylation in PC12 cells but in combination with NGF, the iNOS selective inhibitor s-methylisothiourea (S-MIU; 2.0 mM) maintained Akt phosphorylation up to 2 h. In IMR32 cells, both L-NAME and S-MIU prolonged the activation of Akt. Pretreatment with 50 μM U0126, a MAP kinase pathway inhibitor, also increased the activation of Akt in both cell lines. These data suggest that NO modulates the duration of phosphorylation of Akt in response to NGF and that this effect may, in part, be mediated by the effects of NO on the Ras-MAP kinase pathway.

scholarly journals Binding of Shp2 Tyrosine Phosphatase to FRS2 Is Essential for Fibroblast Growth Factor-Induced PC12 Cell Differentiation

1998 ◽  
Vol 18 (7) ◽  
pp. 3966-3973 ◽  
Author(s):  
Y. R. Hadari ◽  
H. Kouhara ◽  
I. Lax ◽  
J. Schlessinger
Keyword(s):  
Cell Differentiation ◽  
Growth Factor ◽  
Map Kinase ◽  
Fibroblast Growth Factor ◽  
Pc12 Cell ◽  
Tyrosine Phosphatase ◽  
Sh2 Domain ◽  
Fibroblast Growth ◽  
Mitogen Activated Protein ◽  
Docking Protein

ABSTRACT FRS2 is a lipid-anchored docking protein that plays an important role in linking fibroblast growth factor (FGF) and nerve growth factor receptors with the Ras/mitogen-activated protein (MAP) kinase signaling pathway. In this report, we demonstrate that FRS2 forms a complex with the N-terminal SH2 domain of the protein tyrosine phosphatase Shp2 in response to FGF stimulation. FGF stimulation induces tyrosine phosphorylation of Shp2, leading to the formation of a complex containing Grb2 and Sos1 molecules. In addition, a mutant FRS2 deficient in both Grb2 and Shp2 binding induces a weak and transient MAP kinase response and fails to induce PC12 cell differentiation in response to FGF stimulation. Furthermore, FGF is unable to induce differentiation of PC12 cells expressing an FRS2 point mutant deficient in Shp2 binding. Finally, we demonstrate that the catalytic activity of Shp2 is essential for sustained activation of MAP kinase and for potentiation of FGF-induced PC12 cell differentiation. These experiments demonstrate that FRS2 recruits Grb2 molecules both directly and indirectly via complex formation with Shp2 and that Shp2 plays an important role in FGF-induced PC12 cell differentiation.

Nerve Growth Factor Upregulates the PAC1 Promoter by Activating the MAP Kinase Pathway in Rat PC12 Cells

2006 ◽  
Vol 921 (1) ◽  
pp. 390-394 ◽  
Author(s):  
F. JAMEN ◽  
J. C. LADEN ◽  
T. BOUSCHET ◽  
N. RODRIGUEZ-HENCHE ◽  
J. BOCKAERT ◽  
...  
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Nerve Growth ◽  
Map Kinase Pathway ◽  
Kinase Pathway

B-Raf-dependent regulation of the MEK-1/mitogen-activated protein kinase pathway in PC12 cells and regulation by cyclic AMP

1994 ◽  
Vol 14 (10) ◽  
pp. 6522-6530
Author(s):  
R R Vaillancourt ◽  
A M Gardner ◽  
G L Johnson
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Map Kinase ◽  
Protein Kinase A ◽  
Pc12 Cells ◽  
Kinase Activation ◽  
Mitogen Activated Protein ◽  
Epidermal Growth ◽  
Camp Levels ◽  
Kinase A

Growth factor receptor tyrosine kinase regulation of the sequential phosphorylation reactions leading to mitogen-activated protein (MAP) kinase activation in PC12 cells has been investigated. In response to epidermal growth factor, nerve growth factor, and platelet-derived growth factor, B-Raf and Raf-1 are activated, phosphorylate recombinant kinase-inactive MEK-1, and activate wild-type MEK-1. MEK-1 is the dual-specificity protein kinase that selectively phosphorylates MAP kinase on tyrosine and threonine, resulting in MAP kinase activation. B-Raf and Raf-1 are growth factor-regulated Raf family members which regulate MEK-1 and MAP kinase activity in PC12 cells. Protein kinase A activation in response to elevated cyclic AMP (cAMP) levels inhibited B-Raf and Raf-1 stimulation in response to growth factors. Ras.GTP loading in response to epidermal growth factor, nerve growth factor, or platelet-derived growth factor was unaffected by protein kinase A activation. Even though elevated cAMP levels inhibited Raf activation, the growth factor activation of MEK-1 and MAP kinase was unaffected in PC12 cells. The results demonstrate that tyrosine kinase receptor activation of MEK-1 and MAP kinase in PC12 cells is regulated by B-Raf and Raf-1, whose activation is inhibited by protein kinase A, and MEK activators, whose activation is independent of cAMP regulation.

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