The homophilic binding of junctional adhesion molecule-C mediates tumor cell-endothelial cell interactions.

Abstract

The junctional adhesion molecule C (JAM-C) was recently shown to undergo a heterophilic interaction with the leukocyte beta2 integrin Mac-1, thereby mediating interactions between vascular cells in inflammatory cell recruitment. Here, the homophilic interaction of JAM-C is presented and functionally characterized to mediate tumor cell-endothelial cell interactions. Recombinant soluble JAM-C in fluid phase bound to immobilized JAM-C as assessed in a purified system; moreover, JAM-C-transfected Chinese hamster ovary (CHO) cells adhered to immobilized JAM-C. The homophilic interaction of JAM-C was mediated by the isolated amino-terminal Ig domain (D1), but not the carboxyl-terminal Ig domain (D2), of the molecule. Dimerization of JAM-A is dependent on the sequence RVE in the amino-terminal Ig domain. This motif is conserved in JAM-C (Arg64-Ile65-Glu66), and a single amino acid mutation in this motif (E66R) abolished the homophilic interaction of JAM-C. The lung carcinoma cell line NCI-H522 was found to express JAM-C. NCI-H522 cells adhered to immobilized JAM-C, as well as to JAM-C-transfected CHO cells, but not to mock-transfected CHO cells or to CHO cells transfected with the JAM-C mutant (E66R). Adhesion of NCI-H522 cells to JAM-C protein or JAM-C-transfected CHO cells was abolished in the presence of soluble JAM-C or the isolated D1. Furthermore, the adhesion of NCI-H522 cells to endothelial cells was significantly blocked by soluble JAM-C or the isolated D1. Thus, JAM-C undergoes a homophilic interaction via the Arg64-Ile65-Glu66 motif on the membrane-distal Ig domain of the molecule. The homophilic interaction of JAM-C can mediate tumor cell-endothelial cell interactions and may thereby be involved in the process of tumor cell metastasis.

• Authors: Sentot Santoso, Valeria V Orlova, Kaimei Song, Ulrich J Sachs, Cornelia L Andrei-Selmer, Triantafyllos Chavakis
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 280 Issue 43 Pg. 36326-33 (Oct 28 2005) ISSN: 0021-9258 [Print] United States
• PMID: 16118203 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Cell Adhesion Molecules
• Immunoglobulin G
• Immunoglobulins
• JAM3 protein, human
• Membrane Proteins
• Protein Isoforms
• Recombinant Fusion Proteins
• Recombinant Proteins

Topics

• Amino Acid Motifs
• Animals
• CHO Cells
• Cell Adhesion
• Cell Adhesion Molecules (chemistry, physiology)
• Cell Line, Tumor
• Cells, Cultured
• Cricetinae
• Dimerization
• Dose-Response Relationship, Drug
• Endothelial Cells (cytology)
• Endothelium, Vascular (cytology)
• Escherichia coli (metabolism)
• Flow Cytometry
• Humans
• Immunoglobulin G (chemistry)
• Immunoglobulins (chemistry, physiology)
• Membrane Proteins (chemistry, physiology)
• Microscopy, Fluorescence
• Mutation
• Neoplasm Metastasis
• Protein Binding
• Protein Isoforms
• Protein Structure, Tertiary
• Recombinant Fusion Proteins (chemistry)
• Recombinant Proteins (chemistry)
• Surface Plasmon Resonance
• Transfection
• Umbilical Veins (cytology)