Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
Mol Cell. 2013 Jan 10;49(1):172-85. doi: 10.1016/j.molcel.2012.10.003. Epub 2012 Nov 8.
The metabolism of glucose and glutamine, primary carbon sources utilized by mitochondria to generate energy and macromolecules for cell growth, is directly regulated by mTORC1. We show that glucose and glutamine, by supplying carbons to the TCA cycle to produce ATP, positively feed back to mTORC1 through an AMPK-, TSC1/2-, and Rag-independent mechanism by regulating mTORC1 assembly and its lysosomal localization. We discovered that the ATP-dependent TTT-RUVBL1/2 complex was disassembled and repressed by energy depletion, resulting in its decreased interaction with mTOR. The TTT-RUVBL complex was necessary for the interaction between mTORC1 and Rag and formation of mTORC1 obligate dimers. In cancer tissues, TTT-RUVBL complex mRNAs were elevated and positively correlated with transcripts encoding proteins of anabolic metabolism and mitochondrial function-all mTORC1-regulated processes. Thus, the TTT-RUVBL1/2 complex responds to the cell's metabolic state, directly regulating the functional assembly of mTORC1 and indirectly controlling the nutrient signal from Rags to mTORC1.
葡萄糖和谷氨酰胺的代谢是线粒体产生能量和大分子物质用于细胞生长的主要碳源,它们受到 mTORC1 的直接调控。我们发现,葡萄糖和谷氨酰胺通过向 TCA 循环提供碳来产生 ATP,通过一种 AMPK-、TSC1/2-和 Rag 独立的机制正向反馈 mTORC1,该机制通过调节 mTORC1 组装及其溶酶体定位来实现。我们发现,ATP 依赖性的 TTT-RUVBL1/2 复合物在能量耗竭时被解组装并受到抑制,从而减少了其与 mTOR 的相互作用。TTT-RUVBL 复合物对于 mTORC1 和 Rag 之间的相互作用以及 mTORC1 必需二聚体的形成是必需的。在癌症组织中,TTT-RUVBL 复合物的 mRNA 水平升高,与编码合成代谢和线粒体功能相关蛋白的转录本呈正相关——所有这些都是 mTORC1 调控的过程。因此,TTT-RUVBL1/2 复合物对细胞的代谢状态作出反应,直接调节 mTORC1 的功能组装,并间接控制 Rag 向 mTORC1 传递的营养信号。