cAMP-dependent protein kinase type I regulates ethanol-induced cAMP response element-mediated gene expression via activation of CREB-binding protein and inhibition of MAPK

J Biol Chem. 2004 Oct 8;279(41):43321-9. doi: 10.1074/jbc.M406994200. Epub 2004 Aug 6.

Abstract

We have shown that the two types of cAMP-dependent protein kinase (PKA) in NG108-15 cells differentially mediate forskolin- and ethanol-induced cAMP response element (CRE)-binding protein (CREB) phosphorylation and CRE-mediated gene transcription. Activated type II PKA is translocated into the nucleus where it phosphorylates CREB. By contrast, activated type I PKA does not translocate to the nucleus but is required for CRE-mediated gene transcription by inducing the activation of other transcription cofactors such as CREB-binding protein (CBP). We show here that CBP is required for forskolin- and ethanol-induced CRE-mediated gene expression. Forskolin- and ethanol-induced CBP phosphorylation, demonstrable at 10 min, persists up to 24 h. CBP phosphorylation requires type I PKA but not type II PKA. In NG108-15 cells, ethanol and forskolin activation of type I PKA also inhibits several components of the MAPK pathway including B-Raf kinase, ERK1/2, and p90RSK phosphorylation. As a result, unphosphorylated p90RSK no longer binds to nor inhibits CBP. Moreover, MEK inhibition by PD98059 induces a significant increase of CRE-mediated gene activation. Taken together, our findings suggest that inhibition of the MAPK pathway enhances cAMP-dependent gene activation during exposure of NG108-15 cells to ethanol. This mechanism appears to involve type I PKA-dependent phosphorylation of CBP and inhibition of MEK-dependent phosphorylation of p90RSK. Under these conditions p90RSK is no longer bound to CBP, thereby promoting CBP-dependent CREB-mediated gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blotting, Western
  • CREB-Binding Protein
  • Cell Line, Tumor
  • Cell Nucleus / metabolism
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinase Type II
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • Ethanol / pharmacology*
  • Flavonoids / pharmacology
  • Gene Expression Regulation*
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Luciferases / metabolism
  • MAP Kinase Signaling System*
  • Models, Biological
  • Nuclear Proteins / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins B-raf / metabolism
  • Ribosomal Protein S6 Kinases, 90-kDa / metabolism
  • Time Factors
  • Trans-Activators / metabolism
  • Transcriptional Activation

Substances

  • Enzyme Inhibitors
  • Flavonoids
  • Nuclear Proteins
  • Trans-Activators
  • Colforsin
  • Ethanol
  • Cyclic AMP
  • Luciferases
  • CREB-Binding Protein
  • CREBBP protein, human
  • Proto-Oncogene Proteins B-raf
  • Ribosomal Protein S6 Kinases, 90-kDa
  • Cyclic AMP-Dependent Protein Kinase Type II
  • Cyclic AMP-Dependent Protein Kinases
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one