title: PECAM-1 (CD31) functions as a reservoir for and a modulator of tyrosine-phosphorylated beta-catenin.
abstract: Catenins function as regulators of cellular signaling events in addition to their previously documented roles in adherens junction formation and function. Evidence to date suggests that beta and gamma catenins can act as signaling molecules, bind transcriptional factors and translocate to the nucleus. Beta- and gamma-catenin are also major substrates for protein tyrosine kinases, and tyrosine phosphorylation of junctional proteins is correlated with decreased adhesiveness. One way in which catenin functions are modulated is by dynamic incorporation into junctional complexes which controls, in part, the cytoplasmic levels of catenins. Here we show that: (1) vascular endothelial growth factor (VEGF) induces beta-catenin tyrosine phosphorylation in a time-, and dose-dependent manner and that VEGF receptors co-localize to areas of endothelial cell-cell contact in vitro and in vivo. (2) Platelet-endothelial cell adhesion molecule (PECAM)-1 can function as a reservoir for, and modulator of, tyrosine phosphorylated beta-catenin. (3) PECAM-1 can prevent beta-catenin nuclear translocation in transfected SW480 colon carcinoma cells. We suggest that PECAM-1 may play a role in modulating beta-catenin tyrosine phosphorylation levels, localization and signaling and by doing so, functions as an important modulator of the endothelium.
authors.affiliation: Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: N
authors.initials: N
authors.lastname: Ilan
authors.forename: S
authors.initials: S
authors.lastname: Mahooti
authors.forename: D L
authors.initials: DL
authors.lastname: Rimm
authors.forename: J A
authors.initials: JA
authors.lastname: Madri
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D008222:Lymphokines / Q000494:pharmacology; D008954:Models, Biological; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015534:Trans-Activators; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D051176:beta Catenin
chemical_list: C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D016228:Endothelial Growth Factors; D008222:Lymphokines; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D051176:beta Catenin; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases