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.

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

scholarly journals Role of Phosphoinositide 3-Kinase and Endocytosis in Nerve Growth Factor-Induced Extracellular Signal-Regulated Kinase Activation via Ras and Rap1

2000 ◽  
Vol 20 (21) ◽  
pp. 8069-8083 ◽  
Author(s):  
Randall D. York ◽  
Derek C. Molliver ◽  
Savraj S. Grewal ◽  
Paula E. Stenberg ◽  
Edwin W. McCleskey ◽  
...  
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Erk Signaling ◽  
Nerve Growth ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Phosphoinositide 3 Kinase

ABSTRACT Neurotrophins promote multiple actions on neuronal cells including cell survival and differentiation. The best-studied neurotrophin, nerve growth factor (NGF), is a major survival factor in sympathetic and sensory neurons and promotes differentiation in a well-studied model system, PC12 cells. To mediate these actions, NGF binds to the TrkA receptor to trigger intracellular signaling cascades. Two kinases whose activities mediate these processes include the mitogen-activated protein (MAP) kinase (or extracellular signal-regulated kinase [ERK]) and phosphoinositide 3-kinase (PI3-K). To examine potential interactions between the ERK and PI3-K pathways, we studied the requirement of PI3-K for NGF activation of the ERK signaling cascade in dorsal root ganglion cells and PC12 cells. We show that PI3-K is required for TrkA internalization and participates in NGF signaling to ERKs via distinct actions on the small G proteins Ras and Rap1. In PC12 cells, NGF activates Ras and Rap1 to elicit the rapid and sustained activation of ERKs respectively. We show here that Rap1 activation requires both TrkA internalization and PI3-K, whereas Ras activation requires neither TrkA internalization nor PI3-K. Both inhibitors of PI3-K and inhibitors of endocytosis prevent GTP loading of Rap1 and block sustained ERK activation by NGF. PI3-K and endocytosis may also regulate ERK signaling at a second site downstream of Ras, since both rapid ERK activation and the Ras-dependent activation of the MAP kinase kinase kinase B-Raf are blocked by inhibition of either PI3-K or endocytosis. The results of this study suggest that PI3-K may be required for the signals initiated by TrkA internalization and demonstrate that specific endocytic events may distinguish ERK signaling via Rap1 and Ras.

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 Essential Role for Phospholipase D2 Activation Downstream of ERK MAP Kinase in Nerve Growth Factor-stimulated Neurite Outgrowth from PC12 Cells

2004 ◽  
Vol 279 (36) ◽  
pp. 37870-37877 ◽  
Author(s):  
Hiroshi Watanabe ◽  
Takeaki Yokozeki ◽  
Masakazu Yamazaki ◽  
Hideyuki Miyazaki ◽  
Takehiko Sasaki ◽  
...  
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Map Kinase ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Essential Role ◽  
Nerve Growth ◽  
Phospholipase D2

The mitogen-activated protein kinase cascade is activated by B-Raf in response to nerve growth factor through interaction with p21ras

1994 ◽  
Vol 14 (10) ◽  
pp. 6944-6953
Author(s):  
R K Jaiswal ◽  
S A Moodie ◽  
A Wolfman ◽  
G E Landreth
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Map Kinase ◽  
Pc12 Cells ◽  
Mitogen Activated Protein Kinase ◽  
Stable Complex ◽  
Nerve Growth ◽  
Map Kinase Cascade ◽  
Mitogen Activated Protein ◽  
Kinase Cascade

Nerve growth factor (NGF) activates the mitogen-activated protein (MAP) kinase cascade through a p21ras-dependent signal transduction pathway in PC12 cells. The linkage between p21ras and MEK1 was investigated to identify those elements which participate in the regulation of MEK1 activity. We have screened for MEK activators using a coupled assay in which the MAP kinase cascade has been reconstituted in vitro. We report that we have detected a single NGF-stimulated MEK-activating activity which has been identified as B-Raf. PC12 cells express both B-Raf and c-Raf1; however, the MEK-activating activity was found only in fractions containing B-Raf. c-Raf1-containing fractions did not exhibit a MEK-activating activity. Gel filtration analysis revealed that the B-Raf eluted with an apparent M(r) of 250,000 to 300,000, indicating that it is present within a stable complex with other unidentified proteins. Immunoprecipitation with B-Raf-specific antisera quantitatively precipitated all MEK activator activity from these fractions. We also demonstrate that B-Raf, as well as c-Raf1, directly interacted with activated p21ras immobilized on silica beads. NGF treatment of the cells had no effect on the ability of B-Raf or c-Raf1 to bind to activated p21ras. These data indicate that this interaction was not dependent upon the activation state of these enzymes; however, MEK kinase activity was found to be associated with p21ras following incubation with NGF-treated samples at levels higher than those obtained from unstimulated cells. These data provide direct evidence that NGF-stimulated B-Raf is responsible for the activation of the MAP kinase cascade in PC12 cells, whereas c-Raf1 activity was not found to function within this 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 A Novel, Nerve Growth Factor-activated Pathway Involving Nitric Oxide, p53, and p21WAF1Regulates Neuronal Differentiation of PC12 Cells

1997 ◽  
Vol 272 (38) ◽  
pp. 24002-24007 ◽  
Author(s):  
Wojciech Poluha ◽  
Christopher M. Schonhoff ◽  
Kimberly S. Harrington ◽  
Mahesh B. Lachyankar ◽  
Nancy E. Crosbie ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neuronal Differentiation ◽  
Pc12 Cells ◽  
Nerve Growth
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