RGD Reference Report - Extracellular ATP stimulates an inhibitory pathway towards growth factor-induced cRaf-1 and MEKK activation in astrocyte cultures. - Rat Genome Database

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Extracellular ATP stimulates an inhibitory pathway towards growth factor-induced cRaf-1 and MEKK activation in astrocyte cultures.

Authors: Lenz, G  Goncalves, D  Luo, Z  Avruch, J  Rodnight, R  Neary, JT 
Citation: Lenz G, etal., J Neurochem 2001 May;77(4):1001-9.
RGD ID: 724475
Pubmed: PMID:11359865   (View Abstract at PubMed)

ATP, acting via P2Y, G protein-coupled receptors (GPCRs), is a mitogenic signal and also synergistically enhances fibroblast growth factor-2 (FGF-2)-induced proliferation in astrocytes. Here, we have examined the effects of ATP and FGF-2 cotreatment on the main components of the extracellular-signal regulated protein kinase (ERK) cascade, cRaf-1, MAPK/ERK kinase (MEK) and ERK, key regulators of cellular proliferation. Surprisingly, ATP inhibited activation of cRaf-1 by FGF-2 in primary cultures of rat cortical astrocytes. The inhibitory effect did not diminish MEK and ERK activation; indeed, cotreatment resulted in a greater initial activation of ERK. ATP inhibition of cRaf-1 activation was not mediated by an increase in cyclic AMP levels or by protein kinase C activation. ATP also inhibited the activation of cRaf-1 by other growth factors, epidermal growth factor and platelet-derived growth factor, as well as other MEK1 activators stimulated by FGF-2, MEK kinase 1 (MEKK1) and MEKK2. Serotonin, an agonist of another GPCR coupled to ERK, did not inhibit FGF-2-induced cRaf-1 activation, thereby indicating specificity in the ATP-induced inhibitory cross-talk. These findings suggest that ATP stimulates an inhibitory activity that lays upstream of MEK activators and inhibits growth factor-induced activation of cRaf-1 and MEKKS: Such a mechanism might serve to integrate the actions of receptor tyrosine kinases and P2Y-GPCRS:



Molecular Pathway Annotations    Click to see Annotation Detail View

RGD Manual Annotations


  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Map3k2Ratthe extracellular signal-regulated Raf/Mek/Erk signaling pathway   NAS  RGD 
Objects Annotated

Genes (Rattus norvegicus)
Map3k2  (mitogen activated protein kinase kinase kinase 2)


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