title: PECAM-1 isoform-specific activation of MAPK/ERKs and small GTPases: implications in inflammation and angiogenesis.
abstract: Platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31) is expressed on the surface of endothelial cells (EC) and leukocytes. PECAM-1 plays an important role in endothelial-leukocyte and endothelial-endothelial cell-cell interactions. The anti-PECAM-1 antibody-mediated blockade of these interactions inhibits transendothelial migration (TEM) of leukocytes and angiogenesis. PECAM-1 may accommodate these processes through the regulation of cell adhesive and migratory mechanisms. How PECAM-1 regulates these dynamic processes remain unknown. Here we show that PECAM-1 transduces outside-in signals, which activate MAPK/ERKs and small GTPases. This occurs through PECAM-1-mediated formation of intracellular-signaling complexes, Shc/Grb2/SOS1 and/or Crkl/C3G, which is initiated by PECAM-1 engagement on the surface of leukocytes and/or EC. Src, SHP2, and alternative PECAM-1 pre-mRNA splicing play a regulatory role in these signaling events. Our findings reveal that PECAM-1 engagement on the cell surface can transduce "outside-in" signals and activate MAPK/ERKs and small GTPases, impacting both cadherin-mediated cell-cell and integrin-mediated cell-matrix interactions. Thus, we propose PECAM-1 is an important mediator of vascular barrier and regulator of leukocyte and EC adhesion and migration.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, 53792, USA.
authors.forename: Yongji
authors.initials: Y
authors.lastname: Wang
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000502:physiology; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D006410:Hematopoiesis / Q000502:physiology; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D016023:Integrins / Q000502:physiology; D007962:Leukocytes / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000502:physiology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016023:Integrins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D020928:Mitogen-Activated Protein Kinases; D020559:Monomeric GTP-Binding Proteins