Elucidating a mechanism of mTORC1 activation independent of amino acids signaling

阐明独立于氨基酸信号传导的 mTORC1 激活机制

• 批准号: 8550755
• 负责人: David M. Sabatini
• 金额: $ 23.03万
• 依托单位: WHITEHEAD INSTITUTE FOR BIOMEDICAL RES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8550755
• 关键词: Address; Adenoviruses; Affect; Aging; Albumins; Alleles; Amino Acids; Amino Acids Activation; Autophagocytosis; Biogenesis; Breeding; Calnexin; Candidate Disease Gene; Categories; Cell Line; Cells; Complementary DNA; Diabetes Mellitus; Disease; Dominant-Negative Mutation; Down-Regulation; Early Endosome; Excision; Fasting; Gene Expression Profile; Genes; Genetically Engineered Mouse; Golgi Apparatus; Growth; Growth Factor; Guanosine Triphosphate Phosphohydrolases; Hepatocyte; Immunofluorescence Immunologic; Immunoprecipitation; Infection; Institutes; Libraries; Liver; Lysosomes; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Membrane; Membrane Protein Traffic; Messenger RNA; Molecular; Mus; Null Lymphocytes; Nutrient; Organism; PTEN gene; Pathway interactions; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiology; Protein Family; Protein Kinase; Protein Phosphatase 2A Regulatory Subunit PR53; Protein phosphatase; Proteins; Proteomics; RNA Interference; Raptors; Regulation; Resistance; Series; Signal Pathway; Signal Transduction; Sirolimus; Staining method; Stains; Structure; Subfamily lentivirinae; Surface; System; TSC1/2 gene; Technology; Transgenic Mice; Tubulin; Virus; Withdrawal; Work; age related; base; candidate validation; cell growth; cost; deprivation; desensitization; embryo cell; falls; feeding; follow-up; genome-wide; human disease; immortalized cell; improved; in vivo; inhibitor/antagonist; knock-down; liver infection; mouse model; novel; novel therapeutic intervention; novel therapeutics; overexpression; research study; small hairpin RNA; stable cell line

DESCRIPTION (provided by applicant): The mechanisms underlying the pro-aging consequences of mTOR activity are obscure. Deregulated mTOR activity leads to accelerated aging and upregulated mTORC1 activity occurs in aging organisms. We recently described the Rag family of proteins as key for mTORC1 activation by amino acids, through a mechanism that requires mTORC1 shuttling to the lysosomal surface. We have generated a series of immortalized cell lines derived from genetically-engineered mice that lack the RagA gene. Although mTORC1 activity is barely detectable in RagA-deficient embryos, cell lines derived from them have reactivated mTORC1 signaling, which is now insensitive to amino acids withdrawal, but sensitive to growth factors withdrawal. Intriguingly, in these lines mTORC1, although active, does not localize to lysosomes, indicating that an additional unknown mechanism of mTORC1 activation is at work. Based on a combination of transcriptional profiling and proteomic-based approaches, we plan to find the genes responsible for the lysosomal-independent activation of mTORC1 and to understand how this occurs. We will then take advantage of RagA-null livers to study in vivo the consequences of altering the expression of the candidates found. Further elucidation of the molecular mechanism leading to mTORC1 desensitization to amino acid withdrawal, together with the identification of druggable targets within this pathway, may pave the way for novel therapeutic approaches to aging and age-related diseases.

描述（由申请人提供）：mTOR活性的促衰老后果的潜在机制尚不清楚。失调的mTOR活性导致加速老化，并且在老化生物体中发生上调的mTORC1活性。我们最近描述了Rag蛋白家族作为氨基酸激活mTORC 1的关键，通过一种需要mTORC 1穿梭到溶酶体表面的机制。我们已经产生了一系列的永生化细胞系来自基因工程小鼠，缺乏RagA基因。虽然在RagA缺陷的胚胎中几乎检测不到mTORC1活性，但从它们衍生的细胞系重新激活了mTORC1信号传导，该信号传导现在对氨基酸撤回不敏感，但对生长因子撤回敏感。有趣的是，在这些细胞系中，mTORC1虽然有活性，但并不定位于溶酶体，这表明mTORC1激活的另一种未知机制正在起作用。基于转录谱和蛋白质组学方法的结合，我们计划找到负责mTORC 1的溶酶体独立激活的基因，并了解这是如何发生的。然后，我们将利用RagA缺失的肝脏在体内研究改变所发现候选物表达的后果。进一步阐明mTORC 1对氨基酸戒断脱敏的分子机制，以及确定该途径中的可药物靶点，可能为衰老和年龄相关疾病的新型治疗方法铺平道路。