scholarly journals REGULATION OF LEUKOCYTE TRANSENDOTHELIAL MIGRATION BY P120 CATENIN/ VASCULAR ENDOTHELIAL‐CADHERIN

2007 ◽  
Vol 21 (6) ◽  
Author(s):  
Pilar Alcaide ◽  
Gail Newton ◽  
Seema Sehrawat ◽  
Tanya Mayadas‐Norton ◽  
Francis William Luscinskas
2012 ◽  
Vol 303 (4) ◽  
pp. C385-C395 ◽  
Author(s):  
Pilar Alcaide ◽  
Roberta Martinelli ◽  
Gail Newton ◽  
Marcie R. Williams ◽  
Alejandro Adam ◽  
...  

Leukocyte transendothelial migration (TEM) is regulated by several signaling pathways including Src family kinases (SFK) and the small RhoGTPases. Previous studies have shown that vascular endothelial-cadherin (VE-cad) forms a complex with β-,γ-, and p120-catenins and this complex disassociates to form a transient gap during leukocyte TEM. Additionally, p120-catenin (p120-1A) overexpression in human umbilical vein endothelial cells (HUVEC) stabilizes VE-cad surface expression, prevents tyrosine phosphorylation of VE-cad, and inhibits leukocyte TEM. Based on reports showing that p120 overexpression in fibroblasts or epithelial cells inhibits RhoA and activates Rac and Cdc42 GTPases, and on other reports showing that RhoA activation in endothelial cells is necessary for leukocyte TEM, we reasoned that p120 overexpression inhibited TEM through inhibition of RhoA. To test this idea, we overexpressed a mutant p120 isoform, p120-4A, which does not interact with RhoA. p120-4A colocalized with VE-cad in HUVEC junctions and enhanced VE-cad surface expression, similar to overexpression of p120-1A. Interestingly, overexpression of either p120-4A or p120-1A dramatically blocked TEM, and overexpression of p120-1A in HUVEC did not affect RhoA basal activity or activation of RhoA and Rac induced by thrombin or ICAM-1 crosslinking. In contrast, biochemical studies revealed that overexpression of p120-1A reduced activated pY416-Src association with VE-cad. In summary, p120 overexpression inhibits neutrophil TEM independently of an effect on RhoA or Rac and instead blocks TEM by preventing VE-cad tyrosine phosphorylation and association of active Src with the VE-cad complex.


Blood ◽  
2008 ◽  
Vol 112 (7) ◽  
pp. 2770-2779 ◽  
Author(s):  
Pilar Alcaide ◽  
Gail Newton ◽  
Scott Auerbach ◽  
Seema Sehrawat ◽  
Tanya N. Mayadas ◽  
...  

Abstract 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.


2017 ◽  
Vol 28 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Joshua P. Garrett ◽  
Anthony M. Lowery ◽  
Alejandro P. Adam ◽  
Andrew P. Kowalczyk ◽  
Peter A. Vincent

Endothelial p120-catenin (p120) maintains the level of vascular endothelial cadherin (VE-Cad) by inhibiting VE-Cad endocytosis. Loss of p120 results in a decrease in VE-Cad levels, leading to the formation of monolayers with decreased barrier function (as assessed by transendothelial electrical resistance [TEER]), whereas overexpression of p120 increases VE-Cad levels and promotes a more restrictive monolayer. To test whether reduced endocytosis mediated by p120 is required for VE-Cad formation of a restrictive barrier, we restored VE-Cad levels using an endocytic-defective VE-Cad mutant. This endocytic-defective mutant was unable to rescue the loss of TEER associated with p120 or VE-Cad depletion. In contrast, the endocytic-defective mutant was able to prevent sprout formation in a fibrin bead assay, suggesting that p120•VE-Cad interaction regulates barrier function and angiogenic sprouting through different mechanisms. Further investigation found that depletion of p120 increases Src activity and that loss of p120 binding results in increased VE-Cad phosphorylation. In addition, expression of a Y658F–VE-Cad mutant or an endocytic-defective Y658F–VE-Cad double mutant were both able to rescue TEER independently of p120 binding. Our results show that in addition to regulating endocytosis, p120 also allows the phosphorylated form of VE-Cad to participate in the formation of a restrictive monolayer.


2019 ◽  
Vol 128 ◽  
pp. e177-e184 ◽  
Author(s):  
Zhi-peng Xiao ◽  
Jian-lan Zhao ◽  
Wei-lin Rong ◽  
Jin-wen Jiang ◽  
Mei-hua Li

Sign in / Sign up

Export Citation Format

Share Document