Department of Structural Analysis, National Cardiovascular Center Research Institute, Suita, Osaka 565-8565, Japan.
Mol Biol Cell. 2010 Feb 15;21(4):584-96. doi: 10.1091/mbc.e09-07-0580. Epub 2009 Dec 23.
Vascular endothelial (VE)-cadherin is a cell-cell adhesion molecule involved in endothelial barrier functions. Previously, we reported that cAMP-Epac-Rap1 signal enhances VE-cadherin-dependent cell adhesion. Here, we further scrutinized how cAMP-Epac-Rap1 pathway promotes stabilization of VE-cadherin at the cell-cell contacts. Forskolin induced circumferential actin bundling and accumulation of VE-cadherin fused with green fluorescence protein (VEC-GFP) on the bundled actin filaments. Fluorescence recovery after photobleaching (FRAP) analyses using VEC-GFP revealed that forskolin stabilizes VE-cadherin at cell-cell contacts. These effects of forskolin were mimicked by an activator for Epac but not by that for protein kinase A. Forskolin-induced both accumulation and stabilization of junctional VEC-GFP was impeded by latrunculin A. VE-cadherin, alpha-catenin, and beta-catenin were dispensable for forskolin-induced circumferential actin bundling, indicating that homophilic VE-cadherin association is not the trigger of actin bundling. Requirement of alpha- and beta-catenins for forskolin-induced stabilization of VE-cadherin on the actin bundles was confirmed by FRAP analyses using VEC-GFP mutants, supporting the classical model that alpha-catenin could potentially link the bundled actin to cadherin. Collectively, circumferential actin bundle formation and subsequent linkage between actin bundles and VE-cadherin through alpha- and beta-catenins are important for the stabilization of VE-cadherin at the cell-cell contacts in cAMP-Epac-Rap1 signal-activated cells.
血管内皮 (VE)-钙黏蛋白是一种参与内皮屏障功能的细胞间黏附分子。先前,我们报道 cAMP-Epac-Rap1 信号增强了 VE-钙黏蛋白依赖性细胞黏附。在这里,我们进一步研究了 cAMP-Epac-Rap1 途径如何促进 VE-钙黏蛋白在细胞-细胞连接处的稳定。福斯柯林诱导周向肌动蛋白bundling,并将与绿色荧光蛋白 (VEC-GFP) 融合的 VE-钙黏蛋白积累在bundled 肌动蛋白丝上。使用 VEC-GFP 进行荧光恢复后光漂白 (FRAP) 分析表明,福斯柯林稳定了细胞-细胞接触处的 VE-钙黏蛋白。Epac 的激活剂模拟了福斯柯林的这些作用,但蛋白激酶 A 的激活剂则没有。福斯柯林诱导的 juncti onal VEC-GFP 的积累和稳定均被 latrunculin A 所阻碍。VE-钙黏蛋白、α-连环蛋白和β-连环蛋白对于福斯柯林诱导的周向肌动蛋白 bundling 是可有可无的,这表明同源 VE-钙黏蛋白的相互作用不是肌动蛋白 bundling 的触发因素。使用 VEC-GFP 突变体进行 FRAP 分析证实了α-和β-连环蛋白对于福斯柯林诱导的 actin 束上 VE-钙黏蛋白稳定的必要性,这支持了经典模型,即α-连环蛋白可能将bundled 肌动蛋白与钙黏蛋白连接起来。总之,周向肌动蛋白束的形成以及随后通过α-和β-连环蛋白将肌动蛋白束与 VE-钙黏蛋白连接起来,对于 cAMP-Epac-Rap1 信号激活细胞中 VE-钙黏蛋白在细胞-细胞连接处的稳定是很重要的。
Yakugaku Zasshi. 2010-11
FEBS Lett. 2005-9-12
Curr Opin Hematol. 2025-5-1
Am J Physiol Cell Physiol. 2024-10-1
Int J Mol Sci. 2024-6-11
Fluids Barriers CNS. 2023-11-28
Exp Mol Med. 2009-3-31
Nat Rev Mol Cell Biol. 2009-3
Biochim Biophys Acta. 2009-4
FEBS Lett. 2009-1-5
Trends Cell Biol. 2009-1
Nat Rev Mol Cell Biol. 2008-8