Regulation of NF-kappaB RelA phosphorylation and transcriptional activity by p21(ras) and protein kinase Czeta in primary endothelial cells

J Biol Chem. 1999 May 7;274(19):13594-603. doi: 10.1074/jbc.274.19.13594.


The activity of the transcription factor NF-kappaB is thought to be regulated mainly through cytoplasmic retention by IkappaB molecules. Here we present evidence of a second mechanism of regulation acting on NF-kappaB after release from IkappaB. In endothelial cells this mechanism involves phosphorylation of the RelA subunit of NF-kappaB through a pathway involving activation of protein kinase Czeta (PKCzeta) and p21(ras). We show that transcriptional activity of RelA is dependent on phosphorylation of the N-terminal Rel homology domain but not the C-terminal transactivation domain. Inhibition of phosphorylation by dominant negative mutants of PKCzeta or p21(ras) results in loss of RelA transcriptional activity without interfering with DNA binding. Raf/MEK, small GTPases, phosphatidylinositol 3-kinase, and stress-activated protein kinase pathways are not involved in this mechanism of regulation.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cattle
  • Cells, Cultured
  • DNA Primers
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / enzymology
  • Endothelium, Vascular / metabolism*
  • GTP Phosphohydrolases / metabolism
  • Humans
  • Molecular Sequence Data
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism*
  • Oncogene Protein p21(ras) / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Protein Kinase C / metabolism*
  • Proto-Oncogene Proteins c-raf / metabolism
  • Signal Transduction
  • Swine
  • Transcription Factor RelA
  • Transcription, Genetic*
  • Tumor Necrosis Factor-alpha / pharmacology


  • DNA Primers
  • NF-kappa B
  • Transcription Factor RelA
  • Tumor Necrosis Factor-alpha
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-raf
  • protein kinase C zeta
  • Protein Kinase C
  • GTP Phosphohydrolases
  • Oncogene Protein p21(ras)