Tyrosine phosphorylation and the small GTPase rac cross-talk in regulation of endothelial barrier function
Tyrosine phosphorylation and the small GTPase rac cross-talk in regulation of endothelial barrier function
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DOI：
10.1160/th05-01-0015
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发表时间：
2005-08
影响因子：
6.7
通讯作者：
J. Seebach;H. Mädler;B. Wojciak-Stothard;H. Schnittler
中科院分区：
文献类型：
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作者：
J. Seebach;H. Mädler;B. Wojciak-Stothard;H. Schnittler
内皮屏障功能依赖于细胞间粘附连接的完整性，该连接由VE钙粘蛋白/连环蛋白复合物与皮质肌动蛋白丝的结合控制。连接蛋白的酪氨酸磷酸化/去磷酸化和由rho-GTPases介导的肌动蛋白重组都调节屏障功能，但这些调节机制之间的关系尚不清楚。本文研究了蛋白酪氨酸磷酸化增强因子过钒酸盐（PV）和VEGF对人脐静脉内皮细胞（HUVECs）中VE-钙粘蛋白分布、F-肌动蛋白聚合和跨内皮电阻（TER）的影响。细胞质和连接蛋白的蛋白酪氨酸磷酸化的变化，以及rho-GTdR rac 1的活性，也进行了测量。我们首次报道了PV和VEGF诱导内皮屏障功能的快速瞬时增加，并伴有rac 1激活、VE-钙粘蛋白/连环蛋白复合物的分化酪氨酸磷酸化、肌动蛋白丝向细胞连接处的募集和皱褶形成。在PV和VEGF治疗的后期观察到内皮屏障功能持续下降。显性负调控基因rac 1、N17 rac 1的表达可消除PV和VEGF的屏障增强作用，而屏障功能的持续下降不受影响。这些观察使人们关注细胞中蛋白酪氨酸磷酸化的早期短期效应，这些效应往往被更明显和持久的后期效应所掩盖，并且可能在内皮屏障功能的调节中发挥重要作用。
Summary Endothelial barrier function depends on the integrity of intercellular adherens junctions controlled by the association of VEcadherin/ catenin complex with cortical actin filaments. Both tyrosine phosphorylation/dephosphorylation of junctional proteins and actin reorganization mediated by rho-GTPases regulate barrier function but the relationship between these regulatory mechanisms is unclear. Here we studied the effects of factors increasing protein tyrosine phosphorylation, pervanadate (PV) and VEGF, on distribution of VE-cadherin, F-actin polymerization and transendothelial electrical resistance (TER) in human umbilical vein endothelial cells (HUVECs). Changes in protein tyrosine phosphorylation of cytoplasmic and junctional proteins, as well as the activity of rho-GTPase rac1, were also measured. We report for the first time that PV and VEGF induced a rapid transient increase in endothelial barrier function accompanied by rac1 activation, a differentiated tyrosine phosphorylation of theVE-cadherin/catenin complex, recruitment of actin filament to cell junctions and ruffle formation. A sustained decrease in endothelial barrier function was observed at later times of PV and VEGF treatment. Expression of dominant negative rac1, N17rac1 abolished the barrier-enhancing effects of PV andVEGF, while the sustained decrease in barrier function was unaffected. These observations bring into focus early shortterm effects of protein tyrosine phosphorylation in cells, often overshadowed by more pronounced and long-lasting later effects and may play an important role in the regulation of endothelial barrier function.