Localization of VE-cadherin in plasmalemmal cholesterol rich microdomains and the effects of cholesterol depletion on VE-cadherin mediated cell-cell adhesion
Localization of VE-cadherin in plasmalemmal cholesterol rich microdomains and the effects of cholesterol depletion on VE-cadherin mediated cell-cell adhesion
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DOI：
10.1016/j.bbalip.2014.08.016
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发表时间：
2014-12-01
影响因子：
4.8
通讯作者：
Groschner, Klaus
中科院分区：
文献类型：
--
作者：
Baumgartner, Werner;Weth, Agnes;Groschner, Klaus
VE-钙粘蛋白是血管内皮细胞中的主要粘附分子，负责通过与相邻细胞形成粘附接触（粘附连接）来维持内皮屏障功能。我们发现，通过使用单分子荧光显微镜，VE-钙粘蛋白是本地化的预先形成的集群时，没有内部的adherens连接。这些簇依赖于肌动蛋白细胞骨架的完整性，并定位于成熟内皮细胞的富含胆固醇的微区中，如通过膜分离所发现的。利用激光镊子技术探测了形成和维持基于VE-钙粘蛋白的连接的能力，并且我们发现胆固醇消耗对VE-钙粘蛋白介导的粘附具有显著影响。虽然胆固醇水平降低30%导致粘附增加，但约60%的过度胆固醇消耗导致VE-钙粘蛋白功能几乎完全丧失。然而，钙粘蛋白在膜中的浓度和钙粘蛋白的单分子动力学参数没有改变。我们的研究结果表明，肌动蛋白细胞骨架，连接相关的蛋白质和蛋白质-脂质组装在富含胆固醇的微区相互稳定，形成功能性的粘附接触。(C)2014爱思唯尔有限公司版权所有。
VE-cadherin is the predominant adhesion molecule in vascular endothelial cells being responsible for maintenance of the endothelial barrier function by forming adhesive contacts (adherens junctions) to neighbouring cells. We found by use of single molecule fluorescence microscopy that VE-cadherin is localised in preformed clusters when not inside adherens junctions. These clusters depend on the integrity of the actin cytoskeleton and are localised in cholesterol rich microdomains of mature endothelial cells as found by membrane fractionation. The ability to form and maintain VE-cadherin based junctions was probed using the laser tweezer technique, and we found that cholesterol depletion has dramatical effects on VE-cadherin mediated adhesion. While a 30% reduction of the cholesterol-level results in an increase of adhesion, excessive cholesterol depletion by about 60% leads to an almost complete loss of VE-cadherin function. Nevertheless, the cadherin concentration in the membrane and the single molecule kinetic parameters of the cadherin are not changed. Our results suggest that the actin cytoskeleton, junction-associated proteins and protein-lipid assemblies in cholesterol-rich microdomains mutually stabilise each other to form functional adhesion contacts. (C) 2014 Elsevier B.V. All rights reserved.