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Dual interaction of JAM-C with JAM-B and alpha(M)beta2 integrin: function in junctional complexes and leukocyte

Chrystelle Lamagna1, Paolo Meda, Guillaume Mandicourt

  • 1Department of Pathology and Immunology, Centre Médical Universitaire, 1204 Geneva, Switzerland.

Molecular Biology of the Cell
|August 12, 2005
PubMed

Insights

Junctional adhesion molecule B (JAM-B) binding to JAM-C regulates leukocyte adhesion. This interaction controls JAM-C

Area of Science:

  • Cell adhesion biology
  • Immunology
  • Molecular cell biology

Background:

  • Junctional adhesion molecules (JAMs) are key regulators of endothelial cell-cell junctions.
  • JAMs also function as ligands for integrins, mediating cell adhesion processes.

Purpose of the Study:

  • To investigate the heterophilic interaction between JAM-B and JAM-C.
  • To elucidate the role of JAM-B/JAM-C interactions in regulating leukocyte adhesion via alpha(M)beta2 integrin.

Main Methods:

  • Cell-cell contact assays to observe JAM-B and JAM-C interactions.
  • Use of soluble JAM-B and antibodies to modulate JAM interactions.
  • Analysis of leukocyte adhesion to endothelial cells.

Main Results:

  • JAM-B and JAM-C engage in heterophilic interactions, with JAM-B stabilizing JAM-C in junctional complexes.
  • Soluble JAM-B promotes the formation of JAM-B/JAM-C heterodimers over JAM-C homodimers.
  • Blocking JAM-B/JAM-C heterodimerization liberates JAM-C for interaction with leukocyte alpha(M)beta2 integrin, modulating adhesion.

Conclusions:

  • JAM-B binding to JAM-C is a novel mechanism to regulate the localization of JAM-C.
  • Modulation of JAM-C localization at endothelial junctions controls alpha(M)beta2 integrin-dependent leukocyte adhesion.

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