Deciphering the Molecular Mechanisms by which PKA inhibits mTORC1

摘要 哺乳动物雷帕霉素靶蛋白（mTOR）是一种进化上保守的丝氨酸/苏氨酸激酶，可以检测多种雷帕霉素靶蛋白。 上游刺激来调节细胞生长、代谢和自噬。mTOR是一个多功能的关键组件， 蛋白质复合物称为mTOR复合物1（mTORC 1）。mTORC 1激活增加在人类中很常见 疾病，包括癌症、2型糖尿病、代谢紊乱和神经变性。小分子如 靶向并抑制mTORC 1的雷帕霉素目前用于临床，但成功有限。因此， 参与mTORC 1调节的分子机制对于治疗mTORC 1介导的 疾病大多数研究都集中在激活mTORC 1的刺激物上，如生长因子和氨基酸。 acids.相比之下，对可以直接抑制mTORC 1活性的信号通路知之甚少。g蛋白 与Gαs蛋白配对的偶联受体（GPCR）通过增加细胞内 环腺苷酸（cAMP）水平。PKA使mTORC 1组分Raptor磷酸化， 有效抑制mTORC 1活性。重要的是，GPCR是最大的药物靶标家族， 化合物已被FDA批准用于调节GPCR信号传导。我们的初步数据进一步揭示了 详细的机制，并确定参与PKA抑制mTORC 1的新组分（特异性目的1-2）。 此外，我们将确定PKA信号传导在mTORC 1介导的生物学和疾病中的作用（具体目的 3）。因此，本提案的总体目标是破译分子机制， PKA抑制mTORC 1并调节mTORC 1介导的生物学。我们预计， 将对PKA对mTORC 1的调节产生新的见解，并将揭示干扰mTORC 1的治疗靶点。 介导的疾病。

ABSTRACT The mammalian target of rapamycin (mTOR) is an evolutionary conserved Ser/Thr kinase that can sense multiple upstream stimuli to regulate cell growth, metabolism, and autophagy. mTOR is the key component of a multi- protein complex termed mTOR complex 1 (mTORC1). Increased mTORC1 activation is common in human disease including cancer, type 2 diabetes, metabolic disorders, and neurodegeneration. Small molecules like rapamycin that target and inhibit mTORC1, are currently used in the clinic with limited success. Thus, deciphering the molecular mechanisms involved in mTORC1 regulation is crucial in order to treat mTORC1-mediated disease. The majority of research has focused on stimuli that activate mTORC1, like growth factors and amino acids. In contrast, less is known about signaling pathways that can directly inhibit mTORC1 activity. G-protein coupled receptors (GPCRs) paired to Gαs proteins activate Protein Kinase A (PKA) by increasing intracellular cyclic adenosine 3’5’ monophosphate (cAMP) levels. PKA phosphorylates the mTORC1 component Raptor and potently inhibits mTORC1 activity. Importantly, GPCRs are the largest family of drug targets and many compounds have been approved by the FDA to regulate GPCR signaling. Our preliminary data reveals further mechanistic detail and identifies new components involved in mTORC1 inhibition by PKA (Specific Aims 1-2). Moreover, we will determine the role of PKA signaling in mTORC1-mediated biology and disease (Specific Aim 3). Therefore, the overall objective of this proposal is to decipher the molecular mechanisms by which PKA inhibits mTORC1 and regulates mTORC1-mediated biology. We anticipate that the proposed studies will yield new insights into mTORC1 regulation by PKA and will uncover therapeutic targets to perturb mTORC1- mediated disease.