EGF induces efficient Cx43 gap junction endocytosis in mouse embryonic stem cell colonies via phosphorylation of Ser262, Ser279/282, and Ser368.
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.
Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA.
John T
JT
Fong
Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA.
Wutigri
W
Nimlamool
Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA. Electronic address: MFalk@lehigh.edu.
Matthias M
MM
Falk
D000818:Animals; D002450:Cell Communication; D002478:Cells, Cultured; D018920:Coculture Techniques; D018031:Connexin 43 / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000378:metabolism*; D004705:Endocytosis; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000502:physiology*; D017629:Gap Junctions / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D012694:Serine / Q000378:metabolism
D018031:Connexin 43; D012694:Serine; D004815:Epidermal Growth Factor; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases
Connexin43; Cx43 phosphorylation; Epidermal growth factor; Gap junction internalization; Mouse embryonic stem cells