EGF induces efficient Cx43 gap junction endocytosis in mouse embryonic stem cell colonies via phosphorylation of Ser262, Ser279/282, and Ser368

FEBS Lett. 2014 Mar 3;588(5):836-44. doi: 10.1016/j.febslet.2014.01.048. Epub 2014 Jan 31.

Abstract

Gap junctions (GJs) traverse apposing membranes of neighboring cells to mediate intercellular communication by passive diffusion of signaling molecules. We have shown previously that cells endocytose GJs utilizing the clathrin machinery. Endocytosis generates cytoplasmic double-membrane vesicles termed annular gap junctions or connexosomes. However, the signaling pathways and protein modifications that trigger GJ endocytosis are largely unknown. Treating mouse embryonic stem cell colonies - endogenously expressing the GJ protein connexin43 (Cx43) - with epidermal growth factor (EGF) inhibited intercellular communication by 64% and activated both, MAPK and PKC signaling cascades to phosphorylate Cx43 on serines 262, 279/282, and 368. Upon EGF treatment Cx43 phosphorylation transiently increased up to 4-fold and induced efficient (66.4%) GJ endocytosis as evidenced by a 5.9-fold increase in Cx43/clathrin co-precipitation.

Keywords: Connexin43; Cx43 phosphorylation; Epidermal growth factor; Gap junction internalization; Mouse embryonic stem cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Communication
  • Cells, Cultured
  • Coculture Techniques
  • Connexin 43 / metabolism*
  • Embryonic Stem Cells / metabolism*
  • Endocytosis*
  • Enzyme Activation
  • Epidermal Growth Factor / physiology*
  • Gap Junctions / metabolism
  • MAP Kinase Signaling System
  • Mice
  • Mitogen-Activated Protein Kinases / metabolism
  • Phosphorylation
  • Protein Kinase C / metabolism
  • Protein Processing, Post-Translational*
  • Protein Transport
  • Serine / metabolism

Substances

  • Connexin 43
  • Serine
  • Epidermal Growth Factor
  • Protein Kinase C
  • Mitogen-Activated Protein Kinases