Cellular Architecture and Dynamics, Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
Mol Biol Cell. 2009 Oct;20(19):4225-34. doi: 10.1091/mbc.e08-02-0210. Epub 2009 Aug 12.
In endothelial cells specifically, cPLA2alpha translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell-cell junction formation, and the emerging role of cPLA2alpha in intracellular trafficking, we tested whether Golgi-associated cPLA2alpha is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2alpha from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2alpha with the Golgi. Silencing of cPLA2alpha and inhibition of cPLA2alpha enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell-cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2alpha to the Golgi and that in turn, Golgi-associated cPLA2alpha regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell-cell junctions.
在内皮细胞中，cPLA2alpha 响应细胞汇合从细胞质易位到高尔基复合体。考虑到汇合与细胞-细胞连接形成之间的联系，以及 cPLA2alpha 在细胞内运输中的新兴作用，我们测试了高尔基体相关的 cPLA2alpha 是否参与连接蛋白的运输。在这里，我们表明 cPLA2alpha 从细胞质到高尔基复合体的重新分布与黏着连接的成熟相关，并且发生在紧密连接形成之前。使用阻断抗 VE-钙粘蛋白抗体破坏黏着连接会逆转 cPLA2alpha 与高尔基复合体的关联。沉默 cPLA2alpha 和使用各种抑制剂抑制 cPLA2alpha 酶活性会导致跨膜连接蛋白 VE-钙粘蛋白、occludin 和 claudin-5 在细胞-细胞连接处的存在减少，并在高尔基复合体中积累。总的来说，我们的数据支持这样的观点，即 VE-钙粘蛋白触发 cPLA2alpha 向高尔基复合体的重定位，反过来，高尔基体相关的 cPLA2alpha 调节跨膜连接蛋白通过或从高尔基复合体的运输，从而控制内皮细胞-细胞连接的完整性。
