title: PECAM-1 isoform-specific functions in PECAM-1-deficient brain microvascular endothelial cells.
abstract: Platelet endothelial cell adhesion molecule-1 (PECAM-1) is alternatively spliced generating eight isoforms that only differ in the length of their cytoplasmic domain. Multiple isoforms of PECAM-1 are present in the endothelium and their expression levels are regulated during vascular development and angiogenesis. However, the functional significance of PECAM-1 isoforms during these processes remains largely unknown. We recently showed that mouse brain endothelial (bEND) cells prepared from PECAM-1-deficient (PECAM-1-/-) mice differ in their cell adhesive and migratory properties compared to PECAM-1+/+ bEND cells. Here we demonstrate that the restoration of PECAM-1 expression in these cells affects their adhesive and migratory properties in an isoform-specific manner. Expression of Delta14&15 PECAM-1, the predominant isoform present in the mouse endothelium, in PECAM-1-/- bEND cells activated MAPK/ERKs, disrupted adherens junctions, and enhanced cell migration and capillary morphogenesis in Matrigel. In contrast, expression of Delta15 PECAM-1 in PECAM-1-/- bEND cells had minimal effects on their activation of MAPK/ERKs, migration, and capillary morphogenesis. The effects of PECAM-1 on cell adhesive and migratory properties were mediated in an isoform-specific manner, at least in part, through its interactions with intracellular signaling proteins, including SHP-2 and Src. These results suggest that the impact of PECAM-1 on EC adhesion, migration, and capillary morphogenesis is modulated by alternative splicing of its cytoplasmic domain.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53792-4673, USA.
authors.forename: Terri A
authors.initials: TA
authors.lastname: DiMaio
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D017398:Alternative Splicing; D000818:Animals; D000831:Animals, Newborn; D015703:Antigens, CD / Q000378:metabolism; D001921:Brain / Q000098:blood supply*; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D048430:Cell Shape; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008833:Microcirculation / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D051176:beta Catenin / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D020033:Protein Isoforms; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D051176:beta Catenin; D019061:src-Family Kinases; D000099152:Cadherin 5; C495267:CTNNB1 protein, mouse; C516725:Ptpn11 protein, mouse