Regulation of endothelial barrier function by p120-catenin∙VE-cadherin interaction.
Regulation of endothelial barrier function by p120-catenin∙VE-cadherin interaction.
复制标题
P120-catenin∙-cadherin相互作用调节内皮屏障功能。
DOI：
10.1091/mbc.e16-08-0616
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发表时间：
2017-01-01
影响因子：
3.3
通讯作者：
Vincent PA
中科院分区：
文献类型：
--
作者：
Garrett JP;Lowery AM;Adam AP;Kowalczyk AP;Vincent PA
通过p120-连环蛋白结合抑制VE-钙粘蛋白的内吞作用来维持VE-钙粘蛋白水平不足以形成限制性屏障。相反，需要p120-连环蛋白与VE-钙粘蛋白结合，以允许酪氨酸磷酸化的VE-钙粘蛋白有助于屏障形成。内皮细胞p120-连环蛋白（p120）通过抑制血管内皮钙粘蛋白（VE-Cad）的内吞作用来维持VE-Cad的水平。p120的缺失导致VE-Cad水平降低，导致屏障功能降低的单层形成（通过跨内皮电阻[TEER]评估），而p120的过表达增加VE-Cad水平并促进更限制性的单层形成。为了测试是否减少p120介导的内吞作用所需的VE-Cad形成的限制性屏障，我们恢复VE-Cad水平使用内吞缺陷的VE-Cad突变体。这种内吞缺陷突变体不能挽救与p120或VE-Cad耗尽相关的TEER损失。相比之下，内吞缺陷突变体能够在纤维蛋白珠测定中阻止芽的形成，这表明p120·VE-Cad相互作用通过不同的机制调节屏障功能和血管生成芽。进一步的研究发现，p120的耗竭增加Src活性，p120结合的丧失导致VE-Cad磷酸化增加。此外，表达Y 658 F-VE-Cad突变体或内吞缺陷型Y 658 F-VE-Cad双突变体都能够独立于p120结合来拯救TEER。我们的研究结果表明，除了调节内吞作用，p120还允许VE-Cad的磷酸化形式参与限制性单层的形成。
Maintaining VE-cadherin levels by inhibiting its endocytosis through p120-catenin binding is not sufficient for forming a restrictive barrier. Instead, p120-catenin binding to VE-cadherin is required to allow tyrosine-phosphorylated VE-cadherin to contribute to barrier formation. 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.