The E3 ubiquitin ligase ZNRF2 is a substrate of mTORC1 and regulates activation by amino acids
The E3 ubiquitin ligase ZNRF2 is a substrate of mTORC1 and regulates activation by amino acids
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DOI：
10.7554/elife.12278
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发表时间：
2016-04-22
期刊：
影响因子：
7.7
通讯作者：
MacKintosh, Carol
中科院分区：
文献类型：
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作者：
Hoxhaj, Gerta D. K.;Caddye, Edward;MacKintosh, Carol
Rapamycin复合物1的机制靶点（mTORC1）通过一个复杂的机制来感知细胞内氨基酸水平，该机制包括Rag GTPases，调节剂和液泡atp酶（v - atp酶）。膜相关E3泛素连接酶ZNRF2被Akt磷酸化后释放到细胞质中。在这项研究中，我们发现ZNRF2与膜上的mTOR相互作用，促进氨基酸刺激的mTORC1向溶酶体的易位及其在人细胞中的激活。ZNRF2也与v - atp酶相互作用并保持溶酶体酸度。此外，敲低ZNRF2可降低细胞大小和细胞增殖。在生长因子和氨基酸刺激下，mTORC1使ZNRF2的Ser145磷酸化，该磷酸化位点被蛋白磷酸酶6去磷酸化。Ser145磷酸化刺激ZNRF2的囊泡到细胞质易位，并在mTORC1上形成新的负反馈。我们的研究发现ZNRF2是氨基酸传感机制的一个组成部分，它作用于Rag-GTPases和V-ATPase的上游，激活mTORC1。
The mechanistic Target of Rapamycin complex 1 (mTORC1) senses intracellular amino acid levels through an intricate machinery, which includes the Rag GTPases, Ragulator and vacuolar ATPase (V-ATPase). The membrane-associated E3 ubiquitin ligase ZNRF2 is released into the cytosol upon its phosphorylation by Akt. In this study, we show that ZNRF2 interacts with mTOR on membranes, promoting the amino acid-stimulated translocation of mTORC1 to lysosomes and its activation in human cells. ZNRF2 also interacts with the V-ATPase and preserves lysosomal acidity. Moreover, knockdown of ZNRF2 decreases cell size and cell proliferation. Upon growth factor and amino acid stimulation, mTORC1 phosphorylates ZNRF2 on Ser145, and this phosphosite is dephosphorylated by protein phosphatase 6. Ser145 phosphorylation stimulates vesicle-to-cytosol translocation of ZNRF2 and forms a novel negative feedback on mTORC1. Our findings uncover ZNRF2 as a component of the amino acid sensing machinery that acts upstream of Rag-GTPases and the V-ATPase to activate mTORC1.