Linked Life Data

20670916

Source:http://linkedlifedata.com/resource/pubmed/id/20670916

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2010-7-30
pubmed:abstractText
Hepatocyte nuclear factor-4 alpha (HNF-4alpha) is a member of the nuclear receptor superfamily with important roles in hepatic metabolism. Fasting induces the cAMP/protein kinase A (PKA)-signaling pathway. The mechanisms whereby cAMP regulates HNF-4alpha transcriptional activity are incompletely understood. We have therefore investigated the role of cAMP/PKA in regulation of HNF-4alpha in COS-1 cells and the hepatoma HepG2 cell line. cAMP/PKA inhibited the transcriptional activity of HNF-4alpha in COS-1 cells, whereas a stimulatory effect was observed in HepG2 cells. The cAMP-induced inhibition of HNF-4alpha in COS-1 cells was counteracted by overexpression of the nuclear receptor coactivator PGC-1alpha, and cAMP/PKA-dependent induction of the PGC1A gene in HepG2 cells seems to explain the cell specific differences. This was further supported by knock-down of PGC-1alpha in HepG2 cells, which abolished the stimulatory effect of PKA on HNF-4alpha transcriptional activity. Similar to the cAMP/PKA-mediated regulation of HNF-4alpha, overexpression of the cAMP-response element binding protein (CREB) inhibited the transcriptional activity of HNF-4alpha in COS-1 cells, regardless of cAMP/PKA activation and CREB phosphorylation. Moreover, activation of CREB by cAMP/PKA further stimulated HNF-4alpha transactivation in HepG2 cells. cAMP induced the expression of the HNF-4alpha target genes PCK1 and G6Pase in these cells. In conclusion, our results suggest that the level of PGC-1alpha determines whether the cAMP/PKA-pathway overall stimulates or inhibits HNF-4alpha transcriptional activation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-3002
pubmed:author
pubmed:copyrightInfo
Copyright 2010 Elsevier B.V. All rights reserved.
pubmed:issnType
Print
pubmed:volume
1803
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1013-9
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
cAMP-mediated regulation of HNF-4alpha depends on the level of coactivator PGC-1alpha.
pubmed:affiliation
Institute of Medicine, University of Bergen and the Hormone Laboratory, Haukeland University Hospital, N-5021 Bergen, Norway.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't