Regulation of connexin-43 gap junctional intercellular communication by mitogen-activated protein kinase

J Biol Chem. 1998 Apr 10;273(15):9188-96. doi: 10.1074/jbc.273.15.9188.


Activation of the Ras/Raf/mitogen-activated protein kinase kinase/mitogen-activated protein (MAP) kinase signaling cascade is initiated by activation of growth factor receptors and regulates many cellular events, including cell cycle control. Our previous studies suggested that the connexin-43 gap junction protein may be a target of activated MAP kinase and that MAP kinase may regulate connexin-43 function. We identified the sites of MAP kinase phosphorylation in in vitro studies as the consensus MAP kinase recognition sites in the cytoplasmic carboxyl tail of connexin-43, Ser255, Ser279, and Ser282. In this study, we demonstrate that activation of MAP kinase by ligand-induced activation of the epidermal growth factor (EGF) or lysophosphatidic acid receptors or by pervanadate-induced inhibition of tyrosine phosphatases results in increased phosphorylation on connexin-43. EGF and lysophosphatidic acid-induced phosphorylation on connexin-43 and the down-regulation of gap junctional communication in EGF-treated cells were blocked by a specific mitogen-activated protein kinase kinase inhibitor (PD98059) that prevented activation of MAP kinase. These studies confirm that connexin-43 is a MAP kinase substrate in vivo and that phosphorylation on Ser255, Ser279, and/or Ser282 initiates the down-regulation of gap junctional communication. Studies with connexin-43 mutants suggest that MAP kinase phosphorylation at one or more of the tandem Ser279/Ser282 sites is sufficient to disrupt gap junctional intercellular communication.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Cell Communication / drug effects
  • Cell Communication / physiology*
  • Cell Line
  • Connexin 43 / deficiency
  • Connexin 43 / genetics
  • Connexin 43 / physiology*
  • Enzyme Inhibitors / pharmacology
  • Epidermal Growth Factor / pharmacology
  • Flavonoids / pharmacology
  • Gap Junctions / drug effects
  • Gap Junctions / physiology*
  • HeLa Cells
  • Humans
  • Kinetics
  • Lysophospholipids / pharmacology
  • Mice
  • Mice, Knockout
  • Models, Biological
  • Phosphorylation
  • Rats
  • Recombinant Proteins / biosynthesis
  • Serine
  • Signal Transduction*
  • Transfection


  • Connexin 43
  • Enzyme Inhibitors
  • Flavonoids
  • Lysophospholipids
  • Recombinant Proteins
  • Serine
  • Epidermal Growth Factor
  • Calcium-Calmodulin-Dependent Protein Kinases
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one