Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8017, USA.
Am J Physiol Heart Circ Physiol. 2011 Jan;300(1):H162-72. doi: 10.1152/ajpheart.00650.2010. Epub 2010 Oct 29.
To establish the role of vascular endothelial (VE)-cadherin in the regulation of endothelial cell functions, we investigated the effect of phosphorylation of a VE-cadherin site sought to be involved in p120-catenin binding on vascular permeability and endothelial cell migration. To this end, we introduced either wild-type VE-cadherin or Y658 phosphomimetic (Y658E) or dephosphomimetic (Y658F) VE-cadherin mutant constructs into an endothelial cell line (rat fat pad endothelial cells) lacking endogenous VE-cadherin. Remarkably, neither wild-type- nor Y658E VE-cadherin was retained at cell-cell contacts because of p120-catenin preferential binding to N-cadherin, resulting in the targeting of N-cadherin to cell-cell junctions and the exclusion of VE-cadherin. However, Y658F VE-cadherin was able to bind p120-catenin and to localize at adherence junctions displacing N-cadherin. This resulted in an enhanced barrier function and a complete abrogation of Rac1 activation and lamellipodia formation, thereby inhibiting cell migration. These findings demonstrate that VE-cadherin, through the regulation of Y658 phosphorylation, competes for junctional localization with N-cadherin and controls vascular permeability and endothelial cell migration.
为了确定血管内皮钙黏蛋白（VE-钙黏蛋白）在调节内皮细胞功能中的作用，我们研究了VE-钙黏蛋白一个被认为与 p120-连环蛋白结合的磷酸化位点的磷酸化对血管通透性和内皮细胞迁移的影响。为此，我们将野生型 VE-钙黏蛋白或 Y658 磷酸模拟（Y658E）或去磷酸模拟（Y658F）VE-钙黏蛋白突变体构建体引入一种缺乏内源性 VE-钙黏蛋白的内皮细胞系（大鼠脂肪垫内皮细胞）。值得注意的是，由于 p120-连环蛋白优先与 N-钙黏蛋白结合，导致 N-钙黏蛋白靶向细胞-细胞连接处，从而使野生型 VE-钙黏蛋白和 Y658E VE-钙黏蛋白都无法保留在细胞-细胞连接处，而 Y658E VE-钙黏蛋白则无法保留在细胞-细胞连接处。然而，Y658F VE-钙黏蛋白能够与 p120-连环蛋白结合，并定位在黏附连接点，从而排斥 VE-钙黏蛋白。这导致了屏障功能的增强，以及 Rac1 激活和片状伪足形成的完全阻断，从而抑制了细胞迁移。这些发现表明，VE-钙黏蛋白通过调节 Y658 磷酸化，与 N-钙黏蛋白竞争连接点定位，并控制血管通透性和内皮细胞迁移。
