Phosphatidic acid regulation of mTOR signaling

 描述(申请人提供)：雷帕霉素(MTOR)信号网络的哺乳动物靶标是基本细胞和发育过程的主要调节因子，包括细胞生长、增殖、细胞分化和新陈代谢。在癌症、代谢性疾病和神经系统疾病等广泛的人类疾病中都发现了mTOR信号的失调。这项研究的总体目标是了解mTOR复合体1(MTORC1)在细胞生长调节中的信号机制，重点是脂质第二信使磷脂酸(PA)。我们以前的工作确定PA及其生物合成酶磷脂酶D(PLD)是mTORC1有丝分裂和氨基酸激活的关键介质。在当前的赠款周期中，我们对PA调节mTORC1的机制和上游途径有了新的见解。这些最新的发现将我们带入了新的研究方向，有望从分子上更深入地了解这一复杂的信号网络。结合成熟的生化方法和我们最近开发的生物物理方法，我们将在哺乳动物细胞培养的实验系统中剖析PA-mTORC1信号的生化机制。我们的具体目标是(1)研究亮氨酰tRNA合成酶(LRS)作为Vps34-PLD-mTORC1途径的氨基酸感受器，(2)用单分子方法分析PA与mTOR之间的相互作用，以及(3)研究PA调控下的新型mTOR相互作用蛋白。我们的生化和生物物理专业知识以及强大的初步数据使我们处于进行拟议研究的理想位置。实现这些目标可能会导致对mTORC1信号和细胞生长调控的新的机械性见解。所发现的新的调节因子和分子相互作用在未来可能被探索为涉及mTOR的疾病的治疗靶点，如癌症。

 DESCRIPTION (provided by applicant): The mammalian target of rapamycin (mTOR) signaling network is a master regulator of essential cellular and developmental processes, including cell growth, proliferation, cellular differentiation, and metabolism. Dysregulation of mTOR signaling has been found in a wide range of human diseases such as cancer, metabolic diseases, and neurological disorders. The overall goal of the proposed studies is to understand mTOR complex 1 (mTORC1) signaling mechanisms in cell growth regulation, with a focus on the lipid second messenger phosphatidic acid (PA). Our previous work established PA and its biosynthetic enzyme phospholipase D (PLD) as critical mediators of mitogenic and amino acid activation of mTORC1. In the current grant cycle we have gained new insights into the mechanisms and upstream pathways in PA regulation of mTORC1. These recent discoveries have taken us into new directions of investigation with the promise of deeper molecular understanding of this complex signaling network. Combining well-established biochemical approaches with biophysical methods that we have recently developed, we will dissect the biochemical mechanisms of PA- mTORC1 signaling in the experimental system of mammalian cell culture. Our specific aims are to (1) investigate leucyl tRNA synthetase (LRS) as an amino acid sensor for the Vps34-PLD-mTORC1 pathway, (2) dissect the interaction between PA and mTOR using single-molecule assays, and (3) study novel mTOR- interacting proteins under the regulation of PA. Our biochemical and biophysical expertise and strong preliminary data put us in an ideal position to pursue the proposed studies. Accomplishing these aims will likely lead to novel mechanistic insights into mTORC1 signaling and regulation of cell growth. The new regulators and molecular interactions uncovered could be potentially explored in the future as therapeutic targets in diseases involving mTOR, such as cancer.