title: Localization of Tie2 and phospholipase D in endothelial caveolae is involved in angiopoietin-1-induced MEK/ERK phosphorylation and migration in endothelial cells.
abstract: Angiopoietin-1 (Ang1) and its receptor, Tie2, play critical roles in blood vessel formation. Ang1 triggers a variety of signaling events in endothelial cells leading to vasculogenic and angiogenic processes. However, the underlying mechanism for Ang1/Tie2 signaling is not fully understood. Here, we show that Tie2 and phospholipase D (PLD) are localized in the caveolae, specialized subdomains of the endothelial cell plasma membrane enriched with signaling molecules. Interestingly, Ang1 increased PLD activities in a dose- and time-dependent manner. Ang1-induced MEK/ERK activation was abrogated when PLD was inhibited, suggesting that PLD mediates Ang1-induced MEK/ERK activation. Moreover, PLD inhibitor, 1-butanol, inhibited Ang1-induced endothelial cell migration. Our results indicate that: (1) caveolae may be the platform for Tie2/PLD association in endothelial cells; (2) PLD is a new mediator of Ang1/Tie2-induced signaling pathway, and it participates in MAPK activation and endothelial cell migration.
authors.affiliation: National Creative Research Initiatives Center for Endothelial Cells, Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
authors.forename: Mi-Jeong
authors.initials: MJ
authors.lastname: Yoon
authors.forename: Chung-Hyun
authors.initials: CH
authors.lastname: Cho
authors.forename: Chang Sup
authors.initials: CS
authors.lastname: Lee
authors.forename: Il-Ho
authors.initials: IH
authors.lastname: Jang
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Ryu
authors.forename: Gou Young
authors.initials: GY
authors.lastname: Koh
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000502:physiology*; D042683:Angiopoietin-1; D021941:Caveolae / Q000201:enzymology / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D008562:Membrane Glycoproteins / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D042787:Receptor, TIE-2
chemical_list: D043925:Angiogenesis Inducing Agents; D042683:Angiopoietin-1; C105373:MEN1 protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2; D020928:Mitogen-Activated Protein Kinases; D010739:Phospholipase D