Occludin S408 phosphorylation regulates tight junction protein interactions and barrier function

J Cell Biol. 2011 May 2;193(3):565-82. doi: 10.1083/jcb.201010065.


Although the C-terminal cytoplasmic tail of the tight junction protein occludin is heavily phosphorylated, the functional impact of most individual sites is undefined. Here, we show that inhibition of CK2-mediated occludin S408 phosphorylation elevates transepithelial resistance by reducing paracellular cation flux. This regulation requires occludin, claudin-1, claudin-2, and ZO-1. S408 dephosphorylation reduces occludin exchange, but increases exchange of ZO-1, claudin-1, and claudin-2, thereby causing the mobile fractions of these proteins to converge. Claudin-4 exchange is not affected. ZO-1 domains that mediate interactions with occludin and claudins are required for increases in claudin-2 exchange, suggesting assembly of a phosphorylation-sensitive protein complex. Consistent with this, binding of claudin-1 and claudin-2, but not claudin-4, to S408A occludin tail is increased relative to S408D. Finally, CK2 inhibition reversed IL-13-induced, claudin-2-dependent barrier loss. Thus, occludin S408 dephosphorylation regulates paracellular permeability by remodeling tight junction protein dynamic behavior and intermolecular interactions between occludin, ZO-1, and select claudins, and may have therapeutic potential in inflammation-associated barrier dysfunction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caco-2 Cells
  • Claudin-1
  • Claudin-4
  • Claudins
  • Electrophysiology
  • Humans
  • Membrane Proteins / chemistry*
  • Membrane Proteins / metabolism
  • Models, Biological
  • Occludin
  • Permeability
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • RNA, Small Interfering / metabolism
  • Tight Junctions / metabolism*
  • Zonula Occludens-1 Protein


  • CLDN1 protein, human
  • CLDN2 protein, human
  • CLDN4 protein, human
  • Claudin-1
  • Claudin-4
  • Claudins
  • Membrane Proteins
  • OCLN protein, human
  • Occludin
  • Phosphoproteins
  • RNA, Small Interfering
  • TJP1 protein, human
  • Zonula Occludens-1 Protein