Niere Farr, Namjoshi Sanjeev, Song Ehwang, Dilly Geoffrey A, Schoenhard Grant, Zemelman Boris V, Mechref Yehia, Raab-Graham Kimberly F
From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas; ‖Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas;
From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas;
Mol Cell Proteomics. 2016 Feb;15(2):426-44. doi: 10.1074/mcp.M115.055079. Epub 2015 Sep 29.
Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder-neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states.
许多生物学过程都涉及雷帕霉素机制性/哺乳动物靶点复合物1（mTORC1）。因此，在中枢神经系统的正常和病理状态下，解读mTORC1介导的功能面临着挑战。由于mTORC1处于翻译的核心位置，我们研究了mTORC1在全局和区域蛋白质表达中的功能。mTORC1的激活通常被认为能促进翻译。虽然近期相关研究较少，但已有研究表明抑制mTORC1也能促进局部蛋白质合成。此外，疾病状态下mTORC1的过度激活会抑制基础和活动诱导的蛋白质合成。为了确定mTORC1激活在蛋白质表达中的作用，我们采用了一种无偏差的大规模蛋白质组学方法。我们提供的证据表明，雷帕霉素在体内对mTORC1活性的短暂抑制在全局上影响不大，但会导致突触蛋白的显著重塑，特别是那些位于突触后致密区的蛋白质。我们还发现，抑制mTORC1的活性会双向改变与癫痫、阿尔茨海默病和自闭症谱系障碍（这些神经系统疾病均表现出mTORC1活性升高）相关的蛋白质表达。通过蛋白质-蛋白质相互作用网络分析，我们确定了这些与mTORC1相关疾病共有的常见蛋白质。其中一种蛋白质是帕金森病蛋白7，它与帕金森病有关，但与癫痫、阿尔茨海默病或自闭症谱系障碍无关。为了验证我们的发现，我们提供的证据表明，帕金森病蛋白7的蛋白质表达，包括新的蛋白质合成，对mTORC1抑制敏感。使用结节性硬化症的小鼠模型（一种同时表现出癫痫和自闭症谱系障碍表型且mTORC1信号过度活跃的疾病），我们发现帕金森病蛋白7在树突中升高，并与突触后标记物突触后致密蛋白95共定位。我们的工作全面阐述了mTORC1及其在正常和疾病状态下调节区域蛋白质表达中的作用。
