p120-Catenin regulates leukocyte transmigration through an effect on VE-cadherin phosphorylation

• Published in: Blood Vol. 112; no. 7; pp. 2770 - 2779
• Main Authors: Alcaide, Pilar, Newton, Gail, Auerbach, Scott, Sehrawat, Seema, Mayadas, Tanya N., Golan, David E., Yacono, Patrick, Vincent, Peter, Kowalczyk, Andrew, Luscinskas, Francis W.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2008; American Society of Hematology
• Series: Hemostasis, Thrombosis, and Vascular Biology
• Subjects: Antigens, CD - metabolism; Cadherins - metabolism; Catenins; Cell Adhesion Molecules - metabolism; Cells, Cultured; Chemotaxis, Leukocyte; Endocytosis; Endothelial Cells - cytology; Endothelial Cells - metabolism; Endothelium - metabolism; Gap Junctions - metabolism; Green Fluorescent Proteins - metabolism; Half-Life; Hemostasis, Thrombosis, and Vascular Biology; Humans; Leukocytes - cytology; Leukocytes - metabolism; Phosphoproteins - metabolism; Phosphorylation; Protein Binding; Protein Transport; Recombinant Fusion Proteins - metabolism
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2008-03-147181

Vascular endothelial–cadherin (VE-cad) is localized to adherens junctions at endothelial cell borders and forms a complex with α-, β-, γ-, and p120-catenins (p120). We previously showed that the VE-cad complex disassociates to form short-lived “gaps” during leukocyte transendothelial migration (TEM); however, whether these gaps are required for leukocyte TEM is not clear. Recently p120 has been shown to control VE-cad surface expression through endocytosis. We hypothesized that p120 regulates VE-cad surface expression, which would in turn have functional consequences for leukocyte transmigration. Here we show that endothelial cells transduced with an adenovirus expressing p120GFP fusion protein significantly increase VE-cad expression. Moreover, endothelial junctions with high p120GFP expression largely prevent VE-cad gap formation and neutrophil leukocyte TEM; if TEM occurs, the length of time required is prolonged. We find no evidence that VE-cad endocytosis plays a role in VE-cad gap formation and instead show that this process is regulated by changes in VE-cad phosphorylation. In fact, a nonphosphorylatable VE-cad mutant prevented TEM. In summary, our studies provide compelling evidence that VE-cad gap formation is required for leukocyte transmigration and identify p120 as a critical intracellular mediator of this process through its regulation of VE-cad expression at junctions.