The role of long-lived proteins in the survival of nerve cells

 描述(申请人提供)：随着蛋白质老化，它们更容易受到分子损伤。为了对抗蛋白质组的功能衰退，大多数细胞蛋白质被迅速翻转。通过这种方式，潜在受损的多肽不断地被新翻译的拷贝所取代。因此，周转速度较慢的蛋白质遭受有害修饰的风险更大。最近，在大鼠中枢神经系统有丝分裂后细胞中发现了长寿蛋白(LLPs)。值得注意的是，这些LLP与染色质、核膜和质膜相关，所有这些都是协调无数调节功能的细胞间隔。因此，有限合伙人经常暴露在潜在的有害代谢物中。目前尚不清楚这些蛋白质的功能完整性是如何在如此长的时间内保持的，以及这些蛋白质的长寿是否在长寿细胞中扮演着特殊的角色。因此，拟议的实验将测试特定的假设，即LLP在极长的时间范围内调节生物过程，并且它们的功能衰退导致细胞和组织衰老。这项研究计划旨在研究LLP的生物学，主要集中在核孔蛋白和组蛋白，以及它们与有丝分裂后组织功能的关系。首先，将使用定量质谱学和多同位素成像质谱仪来测量大鼠有丝分裂后组织中细胞、细胞器和蛋白质的周转率。其次，将使用生化、细胞生物学和全基因组方法来确定长寿核孔蛋白和组蛋白的分子性质。将致力于识别和表征蛋白质修复途径和保护性的翻译后修饰，这些都是LLP长寿的原因。此外，它还 将确定长寿的核孔蛋白和组蛋白是否分别作为调节核孔功能和基因表达的分子计时器。最后，LLP将在有丝分裂后细胞中被耗尽，使用一种新的蛋白质提取和降解系统来确定LLP损伤如何影响细胞功能和衰老。这些分析将侧重于异常的细胞内贩运和基因调控。拟议的研究有望在蛋白质寿命和衰老之间建立新的联系，并为理解和潜在治疗与年龄相关的退行性疾病提供新的分子靶点。

 DESCRIPTION (provided by applicant): As proteins age they are more likely to acquire molecular damage. To combat the functional decline of the proteome, most cellular proteins are rapidly turned over. In this way, potentially impaired polypeptides are constantly replaced with newly translated copies. Proteins with slower rates of turnover are therefore at greater risk of suffering a deleterious modification. Recently, long-lived proteins (LLPs) were discovered in post-mitotic cells of the rat central nervous system. Strikingly, these LLPs are associated with chromatin, the nuclear envelope, and the plasma membrane, all of which are cellular compartments that coordinate a myriad of regulatory functions. LLPs are therefore constantly exposed to potentially harmful metabolites. It is unknown how the functional integrity of these proteins is maintained over such a long time period, and whether the longevity of these proteins plays a specific role in long-lived cells. Thus, proposed experiments will test the specific hypothesis that LLPs regulate biological processes over extremely long time frames and that their functional decline drives cellular and organismal aging. This research proposal is designed to study the biology of LLPs, primarily focusing on nucleoporins and histones, and how they relate to post-mitotic tissue function. First, quantitative mass spectrometry and multi- isotope imaging mass spectrometry will be used to measure cell, organelle, and protein turnover rates in post-mitotic tissues in rats. Second, biochemical, cell biological, and genome-wide approaches will be used to determine the molecular properties of long-lived nucleoporins and histones. Efforts will be directed toward identifying and characterizing protein-repair pathways and protective post-translational modifications that are responsible for LLP longevity. In addition, it will be determined whether long-lived nucleoporins and histones serve as molecular timers to regulate nuclear pore function and gene expression, respectively. Finally, LLPs will be depleted in post-mitotic cells using a novel protein extraction and degradation system to determine how LLP impairment affects cellular function and aging. These analyses will focus on aberrant intracellular trafficking and gene regulation. Proposed studies promise to establish novel links between protein longevity and aging, and provide new molecular targets for understanding and potentially treating age-associated degenerative disorders.