Neuron-specific deamidation of translational repressor 4E-BP2 in postnatal brain

出生后大脑中翻译抑制子 4E-BP2 的神经元特异性脱酰胺

• 批准号: RGPIN-2020-07050
• 负责人: Khoutorsky, Arkady
• 金额: $ 2.99万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743494
• 关键词: Neuron; specific; deamidation; translational; repressor

Brain development, learning, memory, and perception rely on an intricate network of proteins that orchestrates higher cognitive functions of the human brain. An important biological process regulating the function of these molecules is protein synthesis, also termed translation. Translation controls the mechanisms regulating the strength of connection between neurons, a process called synaptic plasticity. Inhibition of translation blocks the formation of long-term memory and stimulation of translation promotes memory formation. Translation is a tightly regulated process. A key translational control pathway, regulated via the mTORC1 (mechanistic Target of Rapamycin Complex 1 (mTORC1)), is implicated in brain development, synaptic plasticity, learning, and memory. mTORC1 regulates translation in the brain via its major downstream target, 4E-binding protein 2 (4E-BP2). Recent studies have revealed that 4E-BP2 undergoes spontaneous brain-specific asparagine deamidation. However, the mechanisms underlying 4E-BP2 deamidation in the brain and the functional significance of this process remain unknown. Our preliminary data indicate that deamidated form of 4E-BP2 is less stable than wild-type form and its stability is increased in response to inhibition of mTORC1. Given that mTORC1 activity is reduced postnatally, this mechanism might explain the accumulation of deamidated 4E-BP2 during early postnatal brain development. Additionally, we found that translational landscape is altered when deamidated 4E-BP2 is overexpressed in neurons, suggesting that posttranslational modification of 4E-BP2 might regulate the output of mTORC1/4E-BP2 pathway and affect translation of mRNAs in the brain. In the proposed project, we will further investigate the mechanisms underlying 4E-BP2 deamidation and study its effect on brain functions. Specifically, we will generate genetically-modified mice expressing deamidated but not wild-type form of 4E-BP2, and study how neuronal activity and behaviours are affected. We will employ biochemical, electrophysiological, imaging and behavioral approaches to study the impact of 4E-BP2 deamidation on the brain during development and in adulthood. The proposed work will provide fundamental insights into the roles and mechanisms of 4E-BP2 deamidation, altogether advancing our understanding of how translational control shapes brain functions.

大脑发育，学习，记忆和感知依赖于精心策划人脑认知功能的复杂网络。调节这些分子功能的重要生物学过程是蛋白质合成，也称为翻译。翻译控制着调节神经元之间连接强度的机制，该过程称为突触可塑性。翻译的抑制会阻止长期记忆和翻译刺激的形成促进记忆形成。翻译是一个严格调节的过程。通过MTORC1（雷帕霉素复合物1（MTORC1）的机械目标）调节的关键翻译控制途径与大脑发育，突触可塑性，学习和记忆有关。 MTORC1通过其主要下游靶标4E结合蛋白2（4E-BP2）调节大脑中的翻译。最近的研究表明，4E-BP2经历了自发的大脑特异性天冬酰胺脱胺。但是，大脑中4E-BP2脱氨基的基础机制以及该过程的功能意义尚不清楚。 我们的初步数据表明，4E-BP2的脱膜形式不如野生型形式稳定，并且其稳定性因抑制MTORC1而增加。鉴于MTORC1活性在产后降低，因此该机制可能解释了早期产后脑发育期间脱酰胺4E-BP2的积累。此外，我们发现，当脱酰胺4E-BP2在神经元中过表达时，转化景观会改变，这表明4E-BP2的翻译后修饰可能调节MTORC1/4E-BP2途径的输出，并影响大脑中mRNA的转化。在拟议的项目中，我们将进一步研究4E-BP2脱氨基的基础机制，并研究其对脑功能的影响。具体而言，我们将产生表达脱膜但不表达4E-BP2的野生型形式的遗传修饰的小鼠，并研究神经元活性和行为如何影响。我们将采用生化，电生理学，成像和行为方法来研究4E-BP2脱氨化对大脑在发育和成年期间的影响。拟议的工作将提供对4E-BP2脱氨酸的作用和机制的基本见解，从而完全促进我们对翻译控制如何塑造大脑功能的理解。