Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA.
Weill Cornell Medicine, New York, NY, USA.
Sci Signal. 2021 Apr 20;14(679):eabc0425. doi: 10.1126/scisignal.abc0425.
Chloride intracellular channels 1 (CLIC1) and 4 (CLIC4) are expressed in endothelial cells and regulate angiogenic behaviors in vitro, and the expression of is important for vascular development and function in mice. Here, we found that CLIC1 and CLIC4 in endothelial cells regulate critical G protein-coupled receptor (GPCR) pathways associated with vascular development and disease. In cultured endothelial cells, we found that CLIC1 and CLIC4 transiently translocated to the plasma membrane in response to sphingosine 1-phosphate (S1P). Both CLIC1 and CLIC4 were essential for mediating S1P-induced activation of the small guanosine triphosphatase (GTPase) Rac1 downstream of S1P receptor 1 (S1PR1). In contrast, only CLIC1 was essential for S1P-induced activation of the small GTPase RhoA downstream of S1PR2 and S1PR3. Neither were required for other S1P-S1PR signaling outputs. Rescue experiments revealed that CLIC1 and CLIC4 were not functionally interchangeable, suggesting distinct and specific functions for CLICs in transducing GPCR signaling. These CLIC-mediated mechanisms were critical for S1P-induced stimulation of the barrier function in endothelial cell monolayers. Our results define CLICs as previously unknown players in the pathways linking GPCRs to small GTPases and vascular endothelial function.
氯离子细胞内通道 1（CLIC1）和 4（CLIC4）在内皮细胞中表达，并调节体外血管生成行为，而 的表达对小鼠血管发育和功能很重要。在这里，我们发现内皮细胞中的 CLIC1 和 CLIC4 调节与血管发育和疾病相关的关键 G 蛋白偶联受体（GPCR）途径。在培养的内皮细胞中，我们发现 CLIC1 和 CLIC4 会在受到 1-磷酸鞘氨醇（S1P）刺激时瞬时转位到质膜。CLIC1 和 CLIC4 对于介导 S1P 受体 1（S1PR1）下游的小 G 三磷酸鸟苷酶（GTPase）Rac1 的 S1P 诱导激活都是必需的。相反，只有 CLIC1 对于 S1PR2 和 S1PR3 下游的 S1P 诱导的 RhoA 小 GTPase 的激活是必需的。它们都不是其他 S1P-S1PR 信号输出所必需的。挽救实验表明 CLIC1 和 CLIC4 不能在功能上互换，这表明 CLIC 在转导 GPCR 信号方面具有独特而特定的功能。这些 CLIC 介导的机制对于 S1P 诱导的内皮细胞单层屏障功能的刺激至关重要。我们的研究结果将 CLIC 确定为将 GPCR 与小 GTPase 和血管内皮功能联系起来的途径中的未知参与者。
