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

Bonnie J. Warn-Cramer, G. Trevor Cottrell, Janis M. Burt, Alan F. Lau

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305 Scopus citations


Activation of the Ras/Raf/mitogen-activated protein kinase kinase/mitogen-activated protein (MAP) kinase signalling 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-48 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, Set255, 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.

Original languageEnglish (US)
Pages (from-to)9188-9196
Number of pages9
JournalJournal of Biological Chemistry
Issue number15
StatePublished - Apr 10 1998

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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