The functional role of mTORC1 regulation by AMPK in cellular metabolic reprogramming

项目总结 能量动态平衡的丧失是人类疾病的一个关键驱动因素。未能维持细胞能量平衡 导致许多疾病状态，包括糖尿病、癌症和神经疾病。AMP激活的激酶 AMPK是一种高度保守的激酶，负责维持细胞能量平衡。在……条件下 低营养和低能量，AMPK控制代谢从耗能的合成代谢状态切换到 在细胞和生物体水平上都能产生能量的分解代谢状态。在被能量激活时 应激，AMPK磷酸化下游靶标以阻止细胞生长，调节转录，抑制蛋白质 合成，并重新编程细胞新陈代谢。最成熟的下游信号通路之一 被AMPK抑制是雷帕霉素复合体1(MTORC1)途径的促生长机制靶点。然而， MTORC1抑制在细胞代谢重编程和维持能量中的作用 AMPK激活的动态平衡是有争议的，因为AMPK非依赖性抑制mTORC1和 已经描述了代谢途径的mTORC1非依赖调节。 我的研究计划的长期范围是阐明调节能量的机制 动态平衡和完善目前对代谢重编程途径如何施加控制的理解。 为了实现这一长期目标，我的研究小组将解决我们目前 了解mTORC1抑制如何与AMPK活性相互作用以推动细胞新陈代谢和生长： 1)AMPK对细胞代谢重编程是否有必要抑制mTORC1？哪些方面 细胞代谢重编程需要AMPK抑制mTORC1？ 2)mTORC1抑制和AMPK激活如何协调相关过程的调节 在新陈代谢重新编程中？ 我在定义细胞过程的分子机制和使用创新技术方面拥有丰富的专业知识 老鼠模型使我最近成立的独立实验室成为进行这些研究的理想环境 为更完整地理解AMPK信号所做的努力。我们将使用新的点突变小鼠 在依赖AMPK所需的磷酸化位点上存在特定的丝氨酸到丙氨酸突变 MTORC1的抑制作用。利用小鼠组织和来自这些小鼠的原代细胞，我们将进行 功能基因组和生化分析揭示mTORC1抑制的确切作用 AMPK在调节基因表达、自噬和脂质合成中的激活，这些对细胞至关重要 代谢重新编程。总而言之，这些实验将为我们如何思考 AMPK及其与mTORC1的关系，并将提供对这些机制如何失调的洞察 途径可以导致代谢功能障碍和疾病，这将使我们能够确定新的治疗策略 用于治疗与代谢相关的人类疾病。

PROJECT SUMMARY Loss of energy homeostasis is a key driver in human disease. Failure to maintain cellular energy balance results in many disease states, including diabetes, cancer, and neurological diseases. AMP-activated kinase (AMPK) is a highly conserved kinase responsible for maintaining cellular energy balance. Under conditions of low nutrients and low energy, AMPK controls the metabolic switch from an energy-consuming anabolic state to an energy-producing catabolic state at both the cellular and organismal level. Upon activation by energetic stress, AMPK phosphorylates downstream targets to arrest cell growth, regulate transcription, inhibit protein synthesis, and reprogram cellular metabolism. One of the most well-established downstream signaling pathway inhibited by AMPK is the pro-growth mechanistic Target of Rapamycin complex 1 (mTORC1) pathway. However, the functional role that mTORC1 inhibition plays in cellular metabolic reprogramming and maintaining energy homeostasis upon AMPK activation is controversial, as both AMPK-independent inhibition of mTORC1 and mTORC1-independent regulation of metabolic pathways have been described. The long-term scope of my research program is to elucidate the mechanisms that regulate energy homeostasis and refine the current understanding of how pathways exert control of metabolic reprogramming. To accomplish this long-term goal, my research group will address two major knowledge gaps in our current understanding of how mTORC1 inhibition interacts with AMPK activity to drive cellular metabolism and growth: 1) Is mTORC1 inhibition necessary for cellular metabolic reprogramming by AMPK? What aspects of cellular metabolic reprogramming require mTORC1 inhibition by AMPK? 2) How does mTORC1 inhibition and AMPK activation coordinate the regulation of processes involved in metabolic reprogramming? My extensive expertise in defining molecular mechanisms of cellular processes and using innovative mouse models makes my recently established independent laboratory an ideal environment to undertake these efforts toward a more complete understanding of AMPK signaling. We will employ novel point-mutant mice harboring specific serine-to-alanine mutations at the phosphorylation sites required for AMPK-dependent inhibition of mTORC1. Using both mouse tissues and primary cells derived from these mice, we will perform functional genomic and biochemical analyses to uncover the precise role of mTORC1 inhibition induced by AMPK activation in regulating gene expression, autophagy, and lipid synthesis, which are critical for cellular metabolic reprogramming. Together, these experiments will provide conceptual advances in how we think about AMPK and its relationship with mTORC1 and will offer mechanistic insight into how dysregulation of these pathways can lead to metabolic dysfunction and disease, which will allow us to identify new therapeutic strategies for treatment of metabolically-linked human disease.