title: Integrin engagement mediates tyrosine dephosphorylation on platelet-endothelial cell adhesion molecule 1.
abstract: Platelet-endothelial cell adhesion molecule 1 (PECAM-1, CD31) is a 130-kDa member of the immunoglobulin gene superfamily expressed on endothelial cells, platelets, neutrophils, and monocytes and plays a role during endothelial cell migration. Phosphoamino acid analysis and Western blot analysis with anti-phosphotyrosine antibody show that endothelial PECAM-1 is tyrosine-phosphorylated. Phosphorylation is decreased with endothelial cell migration on fibronectin and collagen and with cell spreading on fibronectin but not on plastic. Cell adhesion on anti-integrin antibodies is also able to specifically induce PECAM-1 dephosphorylation while concurrently inducing pp125 focal adhesion kinase phosphorylation. Inhibition of dephosphorylation with sodium orthovanadate suggests that this effect is at least partially mediated by phosphatase activity. Tyr-663 and Tyr-686 are identified as potential phosphorylation sites and mutated to phenylalanine. When expressed, both mutants show reduced PECAM-1 phosphorylation but Phe-686 mutants also show significant reversal of PECAM-1-mediated inhibition of cell migration and do not localize PECAM-1 to cell borders. Our results suggest that beta 1-integrin engagement can signal to dephosphorylate PECAM-1 and that this signaling pathway may play a role during endothelial cell migration.
authors.affiliation: Department of Pathology, Yale University, New Haven, CT 06510, USA.
authors.forename: T T
authors.initials: TT
authors.lastname: Lu
authors.forename: L G
authors.initials: LG
authors.lastname: Yan
authors.forename: J A
authors.initials: JA
authors.lastname: Madri
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D005353:Fibronectins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D008297:Male; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000737:chemistry / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine; D014471:Umbilical Veins
chemical_list: D015815:Cell Adhesion Molecules; D005353:Fibronectins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; C496052:Ptk2 protein, rat; D017027:Protein Tyrosine Phosphatases