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The relationship between the intracellular stability of tyrosine hydroxylase and the neurodegeneration on Parkison's disease

帕金森病细胞内酪氨酸羟化酶稳定性与神经退行性变的关系

基本信息

批准号：
16500247
负责人：
NAKASHIMA Akira
金额：
$ 1.6万
依托单位：
Fujita Health University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

The abnormality of ubiquitin-proteasome system caused by the mutations of alpha-synuclein has been implicated in the pathogenesis of Parkinson's disease. Recently, tyrosine hydroxylase (TH) was found to be a substrate for conjugation to ubiquitin in a reconstituted in vitro system and to be partially degraded by proteasomes in a reticulocyte lysate system. The N-terminus of TH is supposed to be located on the surface of the molecule, and it is presumed to possess flexible conformation susceptible to proteases such as calpain. Therefore, the N-terminus of TH is thought to be a target region for intracellular proteolysis such as occurs in the ubiquitin-proteasome system. Collectively, these results suggest that the N-terminus of TH might play a critical role in the stability of the TH molecule as well as in the regulation of TH catalytic activity in cells.In this research, an experimental scheme was designed in order to prove the influence of the N-terminus on the stability of the TH molecule. At first, we clarified that the deletion of the N-terminus region augmented the intracellular stability of the human TH type 1 molecule and that the accumulation of dopamine in the cells producing the N-terminus-deleted mutants can be attributed to augmented stabilization of the TH molecule. Moreover, computer-assisted analysis of the spatial configuration of human TH type 1 identified 5 newly recognized PEST motifs, the target sequence for proteasome, and one of which was located in the N-terminus sequence of Met^1-Lys^<12>. We believe that this study provides some information to understand the stability of TH protein in mammalian cells and/or the pathogenesis of Parkinson's disease.

α-突触核蛋白突变引起的泛素-蛋白酶体系统异常参与了帕金森病的发病机制。最近，酪氨酸羟化酶(TH)在体外重组体系中被发现是与泛素结合的底物，并在网织红细胞裂解物体系中被蛋白酶体部分降解。TH的N-末端被认为位于分子的表面，并且被认为具有灵活的构象，对钙蛋白酶等蛋白酶敏感。因此，TH的N-末端被认为是泛素-蛋白酶体系统中发生的细胞内蛋白分解的靶区。总之，这些结果表明TH的N末端可能在TH分子的稳定性以及细胞内TH催化活性的调节中起关键作用。在本研究中，设计了一个实验方案来证明N末端对TH分子稳定性的影响。首先，我们阐明了N-末端区域的缺失增强了人类TH-1型分子的细胞内稳定性，并且产生N-末端缺失突变体的细胞中多巴胺的积累可以归因于TH分子的增强稳定性。此外，计算机辅助分析人类TH 1型的空间结构，发现了5个新发现的害虫基序，它们是蛋白酶体的靶序列，其中一个位于Met^1-Lys^&lt；12&gt；的N端序列。我们认为，这项研究为了解哺乳动物细胞中TH蛋白的稳定性和/或帕金森病的发病机制提供了一些信息。