title: Identification of alpha v beta 3 as a heterotypic ligand for CD31/PECAM-1.
abstract: CD31 (PECAM-1) is a member of the immunoglobulin gene superfamily (IgSF) and has an important role in a number of endothelial cell functions including angiogenesis, inflammation, integrin activation and cell-cell adhesion. CD31 has both homotypic and heterotypic adhesive properties and in common with other IgSF members contains multiple functional domains. Using chimaeric fusion proteins of CD31 and a panel of haematopoietic cell lines we show that CD31 can bind cells in a predominantly homotypic or heterotypic manner depending on the cell line used. Heterotypic binding was found to be cation and temperature dependent and enhanced by Mn2+: all features of integrin mediated binding. Using a panel of anti-CD31 and anti-integrin antibodies we show that alpha v beta 3 is a ligand for CD31 on the monocytic cell line U937. The specificity of the interaction between alpha v beta 3 and CD31 was further confirmed by solid phase binding assays and the use of alpha v beta 3 transfected cells which bound CD31 specifically. Furthermore, we have mapped the binding site for alpha v beta 3 to domains 1 and 2 of CD31. The interaction of CD31 with alpha v beta 3 may be important in many aspects of endothelial function including leukocyte-endothelial transmigration and angiogenesis.
authors.affiliation: Cell Adhesion Laboratory, Imperial Cancer Research Fund, John Radcliffe Hospital, Oxford, UK.
authors.forename: C D
authors.initials: CD
authors.lastname: Buckley
authors.forename: R
authors.initials: R
authors.lastname: Doyonnas
authors.forename: J P
authors.initials: JP
authors.lastname: Newton
authors.forename: S D
authors.initials: SD
authors.lastname: Blystone
authors.forename: E J
authors.initials: EJ
authors.lastname: Brown
authors.forename: S M
authors.initials: SM
authors.lastname: Watt
authors.forename: D L
authors.initials: DL
authors.lastname: Simmons
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D001665:Binding Sites; D002412:Cations; D002448:Cell Adhesion; D002460:Cell Line; D018604:Epitope Mapping; D017353:Gene Deletion; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008345:Manganese; D008969:Molecular Sequence Data; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000276:immunology*; D019030:Receptors, Vitronectin / Q000276:immunology*; D011993:Recombinant Fusion Proteins; D013696:Temperature; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D002412:Cations; D006025:Glycosaminoglycans; D008024:Ligands; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D019030:Receptors, Vitronectin; D011993:Recombinant Fusion Proteins; D008345:Manganese