Casein kinase I epsilon associates with and phosphorylates the tight junction protein occludin

FEBS Lett. 2006 Apr 17;580(9):2388-94. doi: 10.1016/j.febslet.2006.03.048.


Occludin is an integral-membrane protein that contributes to tight junction function. We have identified casein kinase I epsilon (CKI epsilon) as a binding partner for the C-terminal cytoplasmic domain of occludin by yeast two-hybrid screening. CKI epsilon phosphorylated occludin and co-localised and co-immunoprecipitated with occludin from human endothelial cells. Amino acids 265-318 of occludin were sufficient for CKI epsilon binding and phosphorylation. Deletion of the C-terminal 48 amino acids of occludin increased CKI epsilon binding and phosphorylation, suggesting that this region inhibits CKI epsilon binding. These data identify CKI epsilon as a novel occludin kinase that may be important for the regulation of occludin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Casein Kinase Iepsilon / genetics
  • Casein Kinase Iepsilon / metabolism*
  • Cells, Cultured
  • Endothelial Cells / cytology
  • Endothelial Cells / enzymology*
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Occludin
  • Phosphorylation
  • Protein Binding / physiology
  • Protein Processing, Post-Translational / physiology*
  • Protein Structure, Tertiary / genetics
  • Sequence Deletion
  • Tight Junctions / enzymology*
  • Tight Junctions / genetics
  • Two-Hybrid System Techniques


  • Membrane Proteins
  • OCLN protein, human
  • Occludin
  • Casein Kinase Iepsilon