Structural mechanism of a Rag GTPase activation checkpoint by the lysosomal folliculin complex
Structural mechanism of a Rag GTPase activation checkpoint by the lysosomal folliculin complex
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DOI：
10.1126/science.aax0364
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发表时间：
2019-11-22
期刊：
影响因子：
56.9
通讯作者：
Zoncu, Roberto
中科院分区：
文献类型：
--
作者：
Lawrence, Rosalie E.;Fromm, Simon A.;Zoncu, Roberto
肿瘤抑制因子卵泡素（FLCN）通过其对鸟苷三磷酸酶（GT3）激活蛋白（GAP）对GT3 RagC的活性，能够营养依赖性激活雷帕霉素复合物1（mTORC 1）蛋白激酶的机制靶点。伴随着mTORC 1失活饥饿，FLCN重新定位从胞质溶胶到溶酶体。为了确定FLCN的溶酶体功能，我们用其溶酶体锚Ragulator复合物重建了人溶酶体FLCN复合物（LFC），该复合物含有FLCN、其伴侣FLCN相互作用蛋白2（FNIP 2）和RagA（GDP）：RagC（GTP）GTP酶（当它们以饥饿状态存在时），并确定其冷冻电子显微镜结构为3.6埃。FLCN的RagC-GAP活性在LFC内被抑制，这是由于FLCN中催化所需的精氨酸从RagC核苷酸被置换。LFC的激活和FLCN的RagC-GAP活性的释放使mTORC 1依赖性调节溶酶体生物发生的主要调节因子，转录因子E3，暗示LFC作为mTORC 1信号传导中的检查点。
The tumor suppressor folliculin (FLCN) enables nutrient-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) protein kinase via its guanosine triphosphatase (GTPase) activating protein (GAP) activity toward the GTPase RagC. Concomitant with mTORC1 inactivation by starvation, FLCN relocalizes from the cytosol to lysosomes. To determine the lysosomal function of FLCN, we reconstituted the human lysosomal FLCN complex (LFC) containing FLCN, its partner FLCN-interacting protein 2 (FNIP2), and the RagA(GDP):RagC(GTP) GTPases as they exist in the starved state with their lysosomal anchor Ragulator complex and determined its cryo-electron microscopy structure to 3.6 angstroms. The RagC-GAP activity of FLCN was inhibited within the LFC, owing to displacement of a catalytically required arginine in FLCN from the RagC nucleotide. Disassembly of the LFC and release of the RagC-GAP activity of FLCN enabled mTORC1- dependent regulation of the master regulator of lysosomal biogenesis, transcription factor E3, implicating the LFC as a checkpoint in mTORC1 signaling.