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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2006-1-20
pubmed:abstractText
One third of all lethal cancers are associated with excessive activation of the Hedgehog (HH) pathway by mutations of its signaling components or by increased responsiveness of cells to the HH ligand. HH signaling through the GLI transcription factors leads to increased cell proliferation by up-regulation of the extracellular regulated kinase (ERK) pathway and by expression of S phase cyclins. In this study, we have tested the hypothesis that the HH pathway can integrate ERK signaling to modulate the activity of GLI. Using NIH 3T3 cells, we show that phorbol esters, acting through protein kinase C-delta (PKCdelta) and mitogen-activated protein/extracellular signal-regulated kinase-1 (MEK-1), fully stimulate the transcriptional activity of endogenous and overexpressed GLI proteins, as assessed by GLI-luciferase reporter assays, and induce the expression of endogenous GLI1 and PTCH-1 target genes, as assessed by reverse transcription-PCR. Moreover, activation of GLI elicited by Sonic Hedgehog also requires PKCdelta and MEK-1 function. Remarkably, coexpression of activated MEK-1 and GLI1 or GLI2 induced a 10-fold synergistic increase in GLI-luciferase activity that was totally blocked by PD98059. The NH(2)-terminal region of GLI1 (amino acids 1-130) is required for sensing the ERK pathway, as deletion of this domain produces active GLI1 protein with greatly reduced response to activation by MEK-1. Basic fibroblast growth factor activation of the ERK pathway also stimulated GLI1 activity through its NH(2)-terminal domain. Our results identify PKCdelta and MEK-1 as essential, positive regulators of GLI-mediated HH signaling. Furthermore, our findings suggest that tumors with deregulated HH and ERK synergize to stimulate cell proliferation pathways.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
839-45
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Protein kinase C-delta and mitogen-activated protein/extracellular signal-regulated kinase-1 control GLI activation in hedgehog signaling.
pubmed:affiliation
Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural