Unexpected role for AMPK and mTORC1 in cellular adaptation to nutrient stress

AMPK 和 mTORC1 在细胞适应营养胁迫中的意外作用

• 批准号: 10790204
• 负责人: Diane C. Fingar
• 金额: $ 1.86万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-22 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10790204
• 关键词: 5' -AMP-activated protein kinase; AMP-activated protein kinase kinase; Amino Acids; Angioplasty; Autophagocytosis; Cell Survival; Cell model; Cells; Cellular Metabolic Process; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; Cues; Cultured Cells; Curiosities; Disease; Engineering; FDA approved; FRAP1 gene; Glucose; Growth Factor; Health; Homeostasis; Insulin; Link; Lipids; Malignant Neoplasms; Metabolic; Metabolic Control; Metabolic Diseases; Metabolism; Metformin; Molecular; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Pathway interactions; Pharmaceutical Preparations; Phosphorylation; Phosphotransferases; Physiological; Protein Kinase; Proteins; Recovery; Renal Cell Carcinoma; Research; Role; Signal Transduction; Site; Starvation; Stents; Stress; Therapeutic; Tissues; Tuberous Sclerosis; Tumor Promoters; Tumor Suppressor Proteins; Work; cell growth; energy balance; feeding; glucophage; inhibitor; mouse model; novel therapeutic intervention; response; restenosis; treatment strategy

Project Summary Signaling networks centered on the conserved protein kinases AMPK (AMP-activated protein kinase) and mTOR (mechanistic target of rapamycin) enable cells to sense and respond appropriately to dynamic fluctuations in a variety of systemic and local cues. Energetic stress activates AMPK to promote catabolic and suppress anabolic pathways to balance energy supply and demand. AMPK also promotes glucose and lipid homeostasis. In fact, the AMPK-activating drug metformin (aka, GlucoPhage) represents the most widely prescribed treatment for type II diabetes. Curiously, AMPK paradoxically functions as a tumor suppressor or tumor promoter depending on cellular context. Nutrients (i.e. amino acids) and growth factors (i.e. IGF/insulin) cooperate to activate mTOR complex 1 (mTORC1), which drives anabolic cell metabolism (i.e. protein and lipid synthesis) and suppresses autophagy. Physiologically, aberrant mTORC1 signaling contributes to diverse disorders including cancer and type II diabetes, and mTOR inhibitors are FDA-approved for renal cell carcinoma, tuberous sclerosis complex (TSC), and stent restenosis following angioplasty. Despite the physiologic and therapeutic importance of AMPK and mTORC1, major gaps exist in our molecular-level understanding of these cell signaling networks. In prior work we showed that phosphorylation of mTOR (on S1261) promotes mTORC1 signaling and cell growth/size. Unexpectedly, a kinome screen identified AMPK as an mTOR S1261 kinase. Finding that AMPK phosphorylates mTOR on an mTORC1-activating site presented an apparent paradox, however, as AMPK canonically inhibits mTORC1 in response to severe energetic stress. Our preliminary results reconcile this paradoxical finding and expose a major gap in our understanding of AMPK and its relationship with mTORC1. We find that after induction of nutrient stress, specifically amino acid starvation, amino acids provided either by re-feeding or autophagy activate AMPK and increase mTOR S1261 phosphorylation, which re-activates mTORC1 signaling and promotes cell survival in an AMPK dependent manner. Moreover, mTOR S1261 phosphorylation requires Rheb, an upstream mTORC1 activator under negative control by TSC. In this proposal we investigate an unexpected role for AMPK and mTORC1 in cellular adaptation to nutrient stress. We hypothesize that the AMPK-mTORC1 axis functions to maintain a survival level of metabolism during prolonged nutrient stress or facilitates metabolic recovery when the stress subsides. This research, which employs cultured cells and a CRISPR-engineered mouse model lacking mTOR S1261 phosphorylation, will provide conceptual advance as it will shift how we think about AMPK in metabolic control and its relationship with mTORC1. Elucidating paradoxical activation of mTORC1 by AMPK will advance our understanding of mTOR and AMPK in health and disease and may identify new therapeutic strategies for treatment of linked disorders, such as cancer and metabolic diseases.

项目摘要 信号网络以保守蛋白激酶AMPK（AMP激活蛋白激酶）为中心 MTOR（雷帕霉素的机理靶标）使细胞能够感知并适当响应动态 各种系统和本地提示的波动。能量应力激活AMPK以促进分解代谢和 抑制合成代谢途径以平衡能源供求。 AMPK还促进葡萄糖和脂质 稳态。实际上，AMPK激活药物二甲双胍（又称葡萄糖量）代表最广泛的 针对II型糖尿病的规定治疗方法。奇怪的是，AMPK矛盾地充当肿瘤抑制剂或 肿瘤启动子取决于细胞环境。营养（即氨基酸）和生长因子（即IGF/胰岛素） 合作激活MTOR复合物1（MTORC1），该复合物驱动合成代谢细胞代谢（即蛋白质和脂质 合成）并抑制自噬。在生理上，异常MTORC1信号传导有助于多样 包括癌症和II型糖尿病和MTOR抑制剂在内的疾病是FDA批准的，用于肾细胞癌， 结节性硬化症复合物（TSC）和血管成形术后的支架再狭窄。尽管有生理和 AMPK和MTORC1的治疗重要性，在我们对这些的分子层面的理解中存在主要差距 细胞信号网络。在先前的工作中，我们表明MTOR的磷酸化（在S1261上）促进了MTORC1 信号传导和细胞生长/大小。出乎意料的是，一个Kinome屏幕将AMPK识别为MTOR S1261激酶。 发现AMPK在MTORC1激活位点上磷酸化MTOR具有明显的悖论， 但是，由于AMPK构成了严重的能量应力，因此canon抑制MTORC1。我们的初步结果 调和这一矛盾的发现，并在我们对AMPK的理解及其与之的关系中揭示了一个重大差距 mtorc1。我们发现，在诱导营养应激，特别是氨基酸饥饿之后，提供了氨基酸 通过重新喂养或自噬激活AMPK并增加MTOR S1261磷酸化，从而重新激活 MTORC1信号传导并以AMPK依赖性方式促进细胞存活。此外，MTOR S1261 磷酸化需要Rheb，Rheb是TSC负面对照的上游MTORC1激活剂。在此提案中 我们研究了AMPK和MTORC1在细胞适应营养应激中的意外作用。我们 假设AMPK-MTORC1轴的功能可在延长过程中维持新陈代谢的存活水平 当应激消退时，营养应激或促进代谢恢复。这项采用文化的研究 细胞和缺少MTOR S1261磷酸化的CRISPR工程的小鼠模型将提供概念 进步会改变我们对代谢控制中AMPK的看法及其与MTORC1的关系。 通过AMPK阐明MTORC1的矛盾激活将提高我们对MTOR和AMPK的理解 健康和疾病，可能会确定新的治疗策略来治疗连接疾病，例如癌症 和代谢疾病。