The role and regulation of mTORC2 in cell migration

项目总结 细胞的定向迁移是一种重要的细胞行为，对正常的生理和放松调控至关重要 在疾病中，包括癌症。然而，细胞如何对迁徙信号做出反应来指导它们的运动却并非如此 明白了。雷帕霉素复合体2的机制靶点(MTORC2)在进化上是保守的 在调节肌动蛋白细胞骨架和控制细胞迁移中的作用。MTORC2是两个 由mTOR激酶形成的多蛋白信号复合体。MTORC1是细胞生长的关键调节因子， 对增殖及其调控和信号通路进行了较好的描述。对mTORC2的了解要少得多， 但最近的研究显示，mTORC2在促进癌细胞迁移和肿瘤扩散方面发挥了作用。 然而，在癌症治疗中靶向mTORC2通路的能力受到缺乏 对mTORC2如何被激活、调节并向细胞运动机械发出信号的机械性洞察。我们 旨在通过确定指导mTORC2活性的关键分子机制来解决这一知识鸿沟 并在细胞迁移中发挥作用。最近，我们发现两个RAS家族的GTP酶，RAS和RAP1，结合 MTOR和mTORC2组件RIP3/SIN1，并控制mTORC2在 实验模型盘基网柄菌。重要的是，我们的初步数据表明，这些mTORC2 调节机制在人类细胞中是保守的。我们的总体目标是确定 以及RAS和Rap1介导的mTORC2活性和功能调节在细胞迁移中的作用。我们的中央 假设RAS和RAP1通过迁移信号独立调节mTORC2 与mTORC2组分的明显相互作用，从而控制细胞内mTORC2的S信号功能 迁移，并在促进癌细胞迁移中发挥关键作用。我们将从三个具体的方面来检验我们的假设 目标。在目标1中，我们将利用mTOR与DictyostelialRas蛋白RASC的相互作用 我们已经确定了RAS介导的mTORC2调控在细胞迁移中的机制和作用， 以网盘基盘基菌为实验模型。在目标2中，我们将确定Rap1在调节mTORC2中的作用 在细胞迁移中的作用，以原型人上皮细胞为实验模型。在《目标3》中，我们将 定义控制乳腺癌细胞迁移的mTORC2通路，应用我们在 在目标1和目标2中进行的机制研究专门询问RAS-和RAP1-的作用- 调控mTORC2促进乳腺癌细胞迁移。总之，拟议的工作将导致 涉及调节mTORC2和细胞迁移的新的分子机制的描述包括 这将为制定治疗策略提供创新机会 抑制癌细胞在转移过程中的迁移。此外，我们的发现还将推动 开发其他涉及细胞病理性迁移的疾病的治疗方法，包括 心血管、炎症和自身免疫性疾病，其中mTOR通路发挥重要作用。

PROJECT SUMMARY The directed migration of cells is an important cellular behavior key to normal physiology and deregulated in disease, including cancer. Yet, how cells direct their movements in response to migration cues is not understood. The mechanistic Target of Rapamycin Complex 2 (mTORC2) plays an evolutionarily conserved role in regulating the actin cytoskeleton and controlling the migration of cells. mTORC2 is one of two multiprotein signaling complexes formed by the mTOR kinase. mTORC1 is a key regulator of cell growth and proliferation, and its regulation and signaling pathway are well described. Much less is known about mTORC2, but recent research revealed a role for mTORC2 in promoting cancer cell migration and tumor dissemination. The ability to target the mTORC2 pathway in cancer therapy, however, is greatly hampered by a lack of mechanistic insight into how mTORC2 is activated, regulated, and signals to the cell motility machinery. We aim to address this knowledge gap by identifying the key molecular mechanisms that direct mTORC2 activity and function in cell migration. Recently, we discovered that two Ras family GTPases, Ras and Rap1, bind mTOR and the mTORC2 component RIP3/SIN1, respectively, and control mTORC2 activity in the experimental model Dictyostelium discoideum. Importantly, our preliminary data indicate that these mTORC2 regulatory mechanisms are conserved in human cells. Our overall objective is to determine the mechanism and role of Ras and Rap1-mediated regulation of mTORC2 activity and function in cell migration. Our central hypothesis is that Ras and Rap1 independently regulate mTORC2 in response to a migration signal through distinct interactions with components of mTORC2, thereby controlling mTORC2's signaling functions in cell migration and playing a key role in promoting cancer cell migration. We will test our hypothesis in three specific aims. In Aim 1, we will take advantage of the mTOR interaction with the Dictyostelium Ras protein RasC that we have identified to define the mechanism and role of Ras-mediated mTORC2 regulation in cell migration, using Dictyostelium as experimental model. In Aim 2, we will identify the role of Rap1 in regulating mTORC2 function in cell migration, using prototypical human epithelial cells as experimental model. In Aim 3, we will define the mTORC2 pathway controlling breast cancer cell migration, applying our findings from the mechanistic studies performed in Aim 1 and Aim 2 to specifically interrogate the role of Ras- and Rap1- regulated mTORC2 in promoting the migration of breast cancer cells. Altogether, the proposed work will lead to the description of novel molecular mechanisms involved in regulating mTORC2 and cell migration, including that of cancer cells, which will provide innovative opportunities for the development of therapeutic strategies for inhibiting the migration of cancer cells in metastasis. Furthermore, our findings will also advance the development of treatments for other diseases that involve the pathological migration of cells, including cardiovascular, inflammatory and autoimmune disorders, in which mTOR pathways play important roles.