The CUL3-SPOP-DAXX axis is a novel regulator of VEGFR2 expression in vascular endothelial cells.
The CUL3-SPOP-DAXX axis is a novel regulator of VEGFR2 expression in vascular endothelial cells.
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DOI：
10.1038/srep42845
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发表时间：
2017-02-20
影响因子：
4.6
通讯作者：
Higashiyama S
中科院分区：
文献类型：
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作者：
Sakaue T;Sakakibara I;Uesugi T;Fujisaki A;Nakashiro KI;Hamakawa H;Kubota E;Joh T;Imai Y;Izutani H;Higashiyama S
血管内皮细胞生长因子受体2（VEGFR 2）是维持内皮细胞稳态的重要受体。在这项研究中，我们发现，NEDD 8结合的Cullin 3（CUL 3）为基础的泛素E3（UbE 3）连接酶在VEGFR 2 mRNA表达中起着至关重要的作用。用MLN 4924（一种NEDD 8激活酶抑制剂）或CUL 3 siRNA处理的人脐静脉内皮细胞由于VEGFR 2表达的强烈降低而显著丧失了对VEGF的应答。此外，斑点型POZ蛋白（SPOP）和死亡结构域相关蛋白（DAXX）分别作为底物接头和底物参与CUL 3 UbE 3连接酶复合物。SPOP和CUL 3的敲低导致DAXX蛋白的上调和VEGFR 2水平的下调。这些水平彼此呈负相关。此外，同时敲除SPOP和DAXX完全逆转了VEGFR 2水平的下调。此外，CUL 3-SPOP-DAXX轴对NOTCH 1、DLL 4和NRP 1的表达具有相同的影响。总之，这些发现表明，CUL 3-SPOP-DAXX轴通过靶向关键的血管生成调节因子在内皮细胞功能中起着非常重要的作用。
Vascular endothelial cell growth factor receptor 2 (VEGFR2) is an essential receptor for the homeostasis of endothelial cells. In this study, we showed that NEDD8-conjugated Cullin3 (CUL3)-based ubiquitin E3 (UbE3) ligase plays a crucial role in VEGFR2 mRNA expression. Human umbilical vein endothelial cells treated with MLN4924, an inhibitor of NEDD8-activating enzyme, or with CUL3 siRNA drastically lost their response to VEGF due to the intense decrease in VEGFR2 expression. Moreover, speckle-type POZ protein (SPOP) and death-domain associated protein (DAXX) were involved in the CUL3 UbE3 ligase complex as a substrate adaptor and a substrate, respectively. Knockdown of SPOP and CUL3 led to the upregulation of DAXX protein and downregulation of VEGFR2 levels. These levels were inversely correlated with one another. In addition, simultaneous knockdown of SPOP and DAXX completely reversed the downregulation of VEGFR2 levels. Moreover, the CUL3-SPOP-DAXX axis had the same effects on NOTCH1, DLL4 and NRP1 expression. Taken together, these findings suggest that the CUL3-SPOP-DAXX axis plays a very important role in endothelial cell function by targeting key angiogenic regulators.