Structure and regulation of human epithelial cell transforming 2 protein
Structure and regulation of human epithelial cell transforming 2 protein
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人上皮细胞转化2蛋白的结构与调控
DOI：
10.1073/pnas.1913054117
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发表时间：
2020-01-14
影响因子：
11.1
通讯作者：
Chen, Zhucheng
中科院分区：
文献类型：
--
作者：
Chen, Mengran;Pan, Han;Chen, Zhucheng
上皮细胞转化蛋白2（Epithelial cell transforming 2，Ect 2）是一种癌蛋白。它激活RhoA并作为细胞分裂，细胞生长和许多其他细胞过程的信号节点发挥作用。它的失调与癌症有关。然而，Ect 2活性的调节知之甚少。我们确定了人Ect 2的晶体结构，并说明了Ect 2调节的机制，包括自抑制和变构激活，这表明RhoA信号传导中存在正反馈回路。总之，我们的研究结果为控制细胞分裂的中央信号轴提供了机制见解，也为未来Ect 2靶向药物开发提供了基础。上皮细胞转化2（Ect 2）蛋白激活Rho GTP酶并控制胞质分裂和许多其他细胞过程。Ect 2的失调与各种癌症有关。在这里，我们报告的晶体结构的人Ect 2和互补的机制分析。数据显示Ect 2的C-末端PH结构域折回并阻断DH结构域催化中心处的典型RhoA结合位点，提供了Ect 2自身抑制的机制。Ect 2通过GTP结合的RhoA与PH结构域的结合而被激活，这表明Ect 2激活的变构机制和增强RhoA信号传导的正反馈环。Ect 2的这种双峰RhoA结合是不寻常的，并与Förster共振能量转移（FRET）和氢氘交换质谱（HDX-MS）分析证实。几个复发性癌症相关突变映射到催化和调节界面，并在体外和体内失调Ect 2。总之，我们的研究结果为正常细胞和疾病条件下的Ect 2调节提供了机制见解。
Significance Epithelial cell transforming 2 (Ect2) is an oncoprotein. It activates RhoA and functions as a signaling node for cell division, cell growth, and many other cellular processes. Its dysregulation is associated with cancers. However, the regulation of Ect2 activity is poorly understood. We determined the crystal structure of human Ect2 and illustrate the mechanisms of Ect2 regulation, including autoinhibition and allosteric activation, which suggests a positive-feedback loop in RhoA signaling. Together, our findings provide mechanistic insights into the central signaling axis that controls cell division, and the basis for future Ect2-targeting drug development as well. Epithelial cell transforming 2 (Ect2) protein activates Rho GTPases and controls cytokinesis and many other cellular processes. Dysregulation of Ect2 is associated with various cancers. Here, we report the crystal structure of human Ect2 and complementary mechanistic analyses. The data show the C-terminal PH domain of Ect2 folds back and blocks the canonical RhoA-binding site at the catalytic center of the DH domain, providing a mechanism of Ect2 autoinhibition. Ect2 is activated by binding of GTP-bound RhoA to the PH domain, which suggests an allosteric mechanism of Ect2 activation and a positive-feedback loop reinforcing RhoA signaling. This bimodal RhoA binding of Ect2 is unusual and was confirmed with Förster resonance energy transfer (FRET) and hydrogen–deuterium exchange mass spectrometry (HDX-MS) analyses. Several recurrent cancer-associated mutations map to the catalytic and regulatory interfaces, and dysregulate Ect2 in vitro and in vivo. Together, our findings provide mechanistic insights into Ect2 regulation in normal cells and under disease conditions.