Regulation of mTOR complexes (mTORCs) by directly acting kinases

通过直接作用的激酶调节 mTOR 复合物 (mTORC)

基本信息

批准号：
9061678
负责人：
Diane C. Fingar
金额：
$ 33.71万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-07-18 至 2018-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9061678
关键词：
5&apos -AMP-activated protein kinase Actins Acute Anabolism Apoptosis Biochemical Biology Cardiovascular Diseases Catalytic Domain Cell Proliferation Cell Survival Cell physiology Cellular Metabolic Process Chronic Clinical Management Complex Cultured Cells Cytoskeleton Data Development Diabetes Mellitus Disease EGF gene Energy Metabolism Event FRAP1 gene Fibroblasts Future Growth Health Homeostasis Host Defense Immune Immunosuppression In Vitro Infection Inflammatory Insulin Resistance Interferons Knowledge Laboratories Link Malignant Neoplasms Mediating Metabolism Mitochondria Molecular Mus Natural Immunity Obesity Pathway interactions Phospho-Specific Antibodies Phosphorylation Phosphotransferases Physiological Physiology Play Process Production Proteins Regulation Renal carcinoma Research Role Signal Transduction Signaling Molecule Site Stimulus Stress TBK1 gene Therapeutic Tumor Promoters Tumor Suppressor Proteins Work cancer cell cell growth cell growth regulation defense response design energy balance human disease immune function in vivo inhibitor/antagonist macrophage microbial novel prevent response sensor targeted treatment tool tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): The mechanistic target of rapamycin (mTOR) responds to diverse environmental signals to control essential cellular functions, playing critical roles in processes related to metabolism, tumorigenesis, and immune function. mTOR constitutes the catalytic core of two functionally distinct signaling complexes, mTORC1 and mTORC2: mTORC1 promotes anabolic cellular processes; while significantly less well understood; mTORC2 promotes cell survival and modulates the actin cytoskeleton. Despite the clear physiologic and therapeutic importance of mTOR, fundamental gaps exist in our knowledge regarding cellular mTOR regulation, especially with regard to the molecular pathways that regulate mTOR activity. Exciting recent work from our laboratory revealed that mTOR phosphorylation plays an important and previously unrecognized role in mTORC1 function. Using phospho specific antibodies and an in vitro kinome screen as tools, we discovered that TBK1/IKKe (kinases that promote innate immune signaling and the host defense response) and AMPK (a kinase that responds to energetic stress) phosphorylate mTOR on distinct sites. Importantly, these phosphorylation events occur in response to physiological signals in cultured cells and in vivo (i.e. mice). Our preliminary data indicate that TBK1/IKKe-mediated phosphorylation of mTOR S2159 promotes mTORC1 signaling while AMPK promotes mTORC2 signaling in response to acute energetic stress. In this application we propose to elucidate roles for these physiologically and pathologically significant signaling molecules in the cellular regulation and function of mTOR. In Aim 1, we investigate the hypothesis that TBK1 and IKKe act directly on mTORC1 to promote growth factor responses and innate immunity; in Aim 2, we investigate the hypothesis that AMPK acts directly on mTORC2 to suppress apoptosis and enhance mitochondrial function to maintain energy homeostasis during acute energetic stress. Emerging data suggest that TBK1/IKKe contribute to chronic inflammatory diseases and obesity-linked insulin resistance; moreover, cancer cells hijack TBK1/IKKe to promote tumorigenesis. As cellular TBK1/IKKe signaling networks remain poorly understood, this research focused on the TBK1/IKKe-mTORC1 axis has potential to impact the future clinical management of chronic inflammatory diseases and cancer. In response to insufficient ATP levels, AMPK stimulates energy producing catabolic and suppresses energy consuming anabolic pathways. This research focused on the AMPK-mTORC2 axis may explain in part the emerging paradox that AMPK can act as a tumor suppressor (by inhibiting cellular anabolism) and a tumor promoter (by inhibiting apoptosis), depending on cellular context. This work will unveil novel regulatory paradigms that directly impact mTOR and will reveal previously unknown links between mTOR and the processes controlled by these kinases, including cell survival, cell metabolism, tumorigenesis, and innate immunity. As the signals that regulate mTORC2 remain virtually unknown, the identification of AMPK as an mTORC2 activator represents a particularly important milestone.

描述（由申请人提供）：雷帕霉素（MTOR）的机械目标响应各种环境信号，以控制基本的细胞功能，发挥关键与代谢，肿瘤发生和免疫功能有关的过程中的作用。 MTOR构成了两个功能上不同信号复合物MTORC1和MTORC2的催化核心：MTORC1促进了合成代谢细胞过程。虽然理解得不多； MTORC2促进细胞存活并调节肌动蛋白细胞骨架。尽管MTOR具有明显的生理和治疗意义，但在我们的细胞MTOR调节方面的知识中仍然存在基本差距，尤其是在调节MTOR活性的分子途径方面。我们实验室的最新工作表明，mTOR磷酸化在MTORC1功能中起着重要且以前未认识到的作用。使用磷酸化的特异性抗体和体外活性筛选作为工具，我们发现TBK1/IKKE（促进先天免疫信号传导和宿主防御反应的激酶）和AMPK（一种响应能量胁迫的激酶）在不同位点上的磷酸化mTOR。重要的是，这些磷酸化事件是响应培养细胞和体内（即小鼠）的生理信号而发生的。我们的初步数据表明 MTOR S2159的TBK1/IKKE介导的磷酸化促进MTORC1信号传导，而AMPK促进MTORC2信号，以响应急性能量应力。在此应用中，我们建议在MTOR的细胞调节和功能中阐明这些生理和病理上显着的信号分子的作用。在AIM 1中，我们研究了TBK1和IKKE直接在MTORC1上起作用以促进生长因子反应和先天免疫的假设。在AIM 2中，我们研究了AMPK直接作用于MTORC2以抑制凋亡并增强线粒体功能以维持急性能量应激期间能量稳态的假设。新兴数据表明，TBK1/IKKE有助于慢性炎症性疾病和肥胖相关的胰岛素抵抗。此外，癌细胞劫持了TBK1/IKKE以促进肿瘤发生。随着细胞TBK1/IKKE信号网络的了解程度不足，该研究的重点是TBK1/IKKE-MTORC1轴有可能影响慢性炎症性疾病和癌症的未来临床管理。为了响应不足的ATP水平，AMPK刺激产生分解代谢的能量并抑制消耗合成代谢途径的能量。这项针对AMPK-MTORC2轴的研究可能部分解释了AMPK可以作为肿瘤抑制因子（通过抑制细胞合成代谢）和肿瘤启动子（通过抑制细胞凋亡），具体取决于细胞的情况，取决于细胞的情况。这项工作将揭示直接影响MTOR的新型调控范例，并将揭示MTOR与这些激酶控制的过程之间的未知联系，包括细胞存活，细胞代谢，肿瘤发生和先天免疫。由于调节MTORC2的信号实际上是未知的，因此将AMPK识别为MTORC2激活剂代表了一个特别重要的里程碑。