Submitted March 26, 2008
Accepted July 7, 2008
p120-catenin regulates leukocyte transmigration through an effect on VE-cadherin phosphorylation
Pilar Alcaide, Gail Newton, Scott Auerbach, Seema Sehrawat, Tanya N. Mayadas, David E. Golan, Patrick Yacono, Peter Vincent, Andrew Kowalczyk, and Francis W. Luscinskas*
Vascular Research Division, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
Department of Biological Chemistry and Molecular Pharmacology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
Center for Cardiovascular Sciences, Albany Medical college, Albany, NY, United States
Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
* Corresponding author; email: fluscinskas{at}rics.bwh.harvard.edu.
Vascular Endothelial-Cadherin (VE-cad) is localized to adherens junctions at endothelial cell borders and forms a complex with
-,
-,
- and p120-catenins (p120). We previously showed that the VE-cad complex disassociates to form short-lived "gaps" during leukocyte transendothelial migration (TEM)1; however, whether these gaps are required for leukocyte TEM is not clear. Recently p120 has been shown to control VE-cad surface expression by 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 increases 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 non-phosphorylatable 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.