Abstract
The junctional adhesion molecules (JAMs) have been recently described as interendothelial junctional molecules and as integrin ligands. Here we show that JAM-B and JAM-C undergo heterophilic interaction in cell-cell contacts and that JAM-C is recruited and stabilized in junctional complexes by JAM-B. In addition, soluble JAM-B dissociates soluble JAM-C homodimers to form JAM-B/JAM-C heterodimers. This suggests that the affinity of JAM-C monomers to form dimers is higher for JAM-B than for JAM-C. Using antibodies against JAM-C, the formation of JAM-B/JAM-C heterodimers can be abolished. This liberates JAM-C from its vascular binding partner JAM-B and makes it available on the apical side of vessels for interaction with its leukocyte counter-receptor alpha(M)beta2 integrin. We demonstrate that the modulation of JAM-C localization in junctional complexes is a new regulatory mechanism for alpha(M)beta2-dependent adhesion of leukocytes.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Cell Adhesion / physiology*
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Cell Adhesion Molecules / genetics
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Cell Adhesion Molecules / metabolism*
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Cell Line
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Coculture Techniques
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Cricetinae
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Cricetulus
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Endothelium / physiology
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Endothelium / ultrastructure
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Green Fluorescent Proteins / genetics
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Humans
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Immunoglobulins / genetics
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Immunoglobulins / metabolism*
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Intercellular Junctions / physiology*
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Intercellular Junctions / ultrastructure
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Leukocytes / physiology*
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Leukocytes / ultrastructure
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Macrophage-1 Antigen / metabolism*
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Mice
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Mice, Inbred C57BL
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Microscopy, Immunoelectron
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Oligopeptides
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Peptides / genetics
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
Substances
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Cell Adhesion Molecules
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Immunoglobulins
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Macrophage-1 Antigen
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Oligopeptides
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Peptides
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Recombinant Fusion Proteins
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enhanced green fluorescent protein
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Green Fluorescent Proteins
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FLAG peptide