aPKC phosphorylates JAM-A at Ser285 to promote cell contact maturation and tight junction formation

J Cell Biol. 2012 Mar 5;196(5):623-39. doi: 10.1083/jcb.201104143. Epub 2012 Feb 27.

Abstract

The PAR-3-atypical protein kinase C (aPKC)-PAR-6 complex has been implicated in the development of apicobasal polarity and the formation of tight junctions (TJs) in vertebrate epithelial cells. It is recruited by junctional adhesion molecule A (JAM-A) to primordial junctions where aPKC is activated by Rho family small guanosine triphosphatases. In this paper, we show that aPKC can interact directly with JAM-A in a PAR-3-independent manner. Upon recruitment to primordial junctions, aPKC phosphorylates JAM-A at S285 to promote the maturation of immature cell-cell contacts. In fully polarized cells, S285-phosphorylated JAM-A is localized exclusively at the TJs, and S285 phosphorylation of JAM-A is required for the development of a functional epithelial barrier. Protein phosphatase 2A dephosphorylates JAM-A at S285, suggesting that it antagonizes the activity of aPKC. Expression of nonphosphorylatable JAM-A/S285A interferes with single lumen specification during cyst development in three-dimensional culture. Our data suggest that aPKC phosphorylates JAM-A at S285 to regulate cell-cell contact maturation, TJ formation, and single lumen specification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Cell Line
  • Cell Polarity / physiology
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Humans
  • Mice
  • Mitosis / physiology
  • Molecular Sequence Data
  • Morphogenesis / physiology
  • Phosphorylation
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Phosphatase 2 / metabolism
  • RNA Interference
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Serine / metabolism*
  • Tight Junctions / physiology*

Substances

  • Cell Adhesion Molecules
  • F11r protein, mouse
  • Receptors, Cell Surface
  • Serine
  • PKC-3 protein
  • Protein Kinase C
  • Protein Phosphatase 2