PECAM-1/CD31 trans-homophilic binding at the intercellular junctions is independent of its cytoplasmic domain; evidence for heterophilic interaction with integrin alphavbeta3 in Cis.
PECAM-1/CD31 is a cell adhesion and signaling molecule that is enriched at the endothelial cell junctions. Alternative splicing generates multiple PECAM-1 splice variants, which differ in their cytoplasmic domains. It has been suggested that the extracellular ligand-binding property, homophilic versus heterophilic, of these isoforms is controlled by their cytoplasmic tails. ... To determine whether the cytoplasmic domains also regulate the cell surface distribution of PECAM-1 splice variants, we examined the distribution of CD31-EGFPs (PECAM-1 isoforms tagged with the enhanced green fluorescent protein) in living Chinese hamster ovary cells and in PECAM-1-deficient endothelial cells. Our results indicate that the extracellular, rather than the cytoplasmic domain, directs PECAM-1 to the cell-cell borders. Furthermore, coculturing PECAM-1 expressing and deficient cells along with transfection of CD31-EGFP cDNAs into PECAM-1 deficient cells reveal that this PECAM-1 localization is mediated by homophilic interactions. Although the integrin alphavbeta3 has been shown to interact with PECAM-1, this trans-heterophilic interaction was not detected at the borders of endothelial cells. However, based on cocapping experiments performed on proT cells, we provide evidence that the integrin alphavbeta3 associates with PECAM-1 on the same cell surface as in a cis manner.
Mesh Terms:
Alternative Splicing, Animals, Antigens, CD31, CHO Cells, Capillaries, Cell Line, Cells, Cultured, Cerebrovascular Circulation, Cricetinae, Cytoplasm, Endothelium, Vascular, Exons, Green Fluorescent Proteins, Intercellular Junctions, Luminescent Proteins, Mice, Mice, Knockout, Models, Molecular, Protein Conformation, Receptors, Vitronectin, Recombinant Fusion Proteins, Signal Transduction, Transfection
Alternative Splicing, Animals, Antigens, CD31, CHO Cells, Capillaries, Cell Line, Cells, Cultured, Cerebrovascular Circulation, Cricetinae, Cytoplasm, Endothelium, Vascular, Exons, Green Fluorescent Proteins, Intercellular Junctions, Luminescent Proteins, Mice, Mice, Knockout, Models, Molecular, Protein Conformation, Receptors, Vitronectin, Recombinant Fusion Proteins, Signal Transduction, Transfection
Mol. Biol. Cell
Date: Sep. 01, 2000
PubMed ID: 10982404
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