Specifying Control Over Ion Balance and Glucose Homeostasis Through mTORC2

描述(由申请人提供)：这项研究计划的总体目标是利用生化、电生理、代谢、遗传和整体动物生理学技术，进一步阐明mTORC2靶标特异性的分子机制及其在调节葡萄糖稳态和离子平衡中的功能意义。K01指导职业发展奖的申请者Catherine E.Gleason博士目前是加州大学旧金山分校David Pearce博士实验室的博士后研究员。格里森博士的长期研究目标是研究代谢信号通路如何相交并影响控制各种生物功能的通路，特别是肾脏的离子平衡，以维持生理内平衡。格里森博士的长期职业目标是建立一个独立的分子生理学研究项目，在一家学术机构担任终身教职研究员。SGK1和Akt是高度相关的蛋白激酶，分别作为控制离子和代谢动态平衡的信号通路的关键中介。最近，mTORC2被确定为通过其疏水基序(HM)中关键的同源残基的磷酸化来激活这些激酶的激酶。由于诱导mTORC2活性的刺激物，如胰岛素和IGF1，都会触发SGK1和Akt的磷酸化，所以mTORC2如何能够以一种允许它们介导对电解质平衡和能量代谢的不同影响的方式来调节这些相关激酶的活性尚不清楚。值得注意的是，肾脏除了在离子平衡中起着公认的作用外，还起着 由于其显著的糖异生能力，在整个动物能量平衡中起着重要的作用。目前尚不清楚肾脏如何能够对多个信号通路中的串扰进行分类，以便对其代谢和离子平衡功能进行适当的、上下文相关的调节。因此，了解围绕mTORC2选择性激活SGK1和Akt的分子动力学，无论是在体外还是在体内，都是开放和重要的研究领域。Gleason博士将以她在代谢生理学和信号转导方面的背景为基础，在细胞和整体动物研究离子转运过程方面进行额外的培训，以解决mTORC2针对SGK1和Akt的特异性的机制基础，以及它们在细胞和整个动物水平上的功能影响，具体目的有两个：1)研究调节SGK1和Akt的mTORC2特异性激活的激素刺激和/或细胞条件。2)研究Akt和SGK1在体内对肾脏葡萄糖代谢和离子平衡的相对贡献。K01指导职业发展奖提供的培训时间将为格里森博士提供一个全面的工具箱，用于她的独立职业生涯，研究新陈代谢与健康和疾病中不同信号通路的交叉点。

DESCRIPTION (provided by applicant): The overall goal of this research proposal is to further elucidate the molecular mechanisms that underlie mTORC2 target specificity and their functional implications in the regulation of glucose homeostasis and ion balance, using biochemical, electrophysiological, metabolic, genetic and whole animal physiology techniques. The applicant for the K01 Mentored Career Development Award, Dr. Catherine E. Gleason, is currently a postdoctoral fellow in Dr. David Pearce's laboratory at UCSF. Dr. Gleason's long-term research goal is to study how metabolic signaling pathways intersect and influence pathways controlling various biological functions, notably ion balance by the kidney, for maintenance of physiological homeostasis. Dr. Gleason's long-term career goal is to establish an independent molecular physiology research program as a tenure-track investigator at an academic institution. SGK1 and Akt are highly related protein kinases that function as key mediators of the signaling pathways that control ion and metabolic homeostasis, respectively. Recently, mTORC2 was identified as the kinase responsible for activation of these kinases by phosphorylation of a critical, homologous residue in their hydrophobic motif (HM). Since, stimuli that induce mTORC2 activity, such as insulin and IGF1, trigger phosphorylation of both SGK1 and Akt, how mTORC2 is able to modulate activity of these related kinases in such a way that allows them to mediate distinct effects on electrolyte balance and energy metabolism is not understood. Notably, in addition to its well-established role in ion balance, the kidney also plays an important role in whole animal energy homeostasis due to its significant gluconeogenic capacity. It is unclear how the kidney is able to sort crosstalk from multiple signaling pathways to allow for appropriate, context-dependent regulation of its metabolic and ion balance functions. Thus, understanding the molecular dynamics surrounding mTORC2 selective activation of SGK1 and Akt, in vitro and in vivo, are open and important areas for investigation. Dr. Gleason will build on her background in metabolic physiology and signal transduction with additional training in the cellular and whole animal study of ion transport processes to address the mechanistic basis for mTORC2 specificity towards SGK1 vs. Akt and their functional implications at the cellular and whole animal levels through two specific aims: 1) Investigate the hormonal stimuli and/or cellular conditions that regulate mTORC2 specific activation of SGK1 vs. Akt. 2) Characterize the relative contributions of Akt and SGK1 towards renal glucose metabolism and ion balance in vivo. The training period provided by the K01 Mentored Career Development Award will provide Dr. Gleason with a comprehensive toolbox for her independent career investigating the intersections of metabolism with diverse signaling pathways in health and disease.