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The relationship between the intracellular stability of tyrosine hydroxylase and the neurodegeneration regulated by α-synuclein

酪氨酸羟化酶细胞内稳定性与α-突触核蛋白调控的神经退行性变的关系

基本信息

批准号：
18500301
负责人：
NAKASHIMA Akira
金额：
$ 1.98万
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：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18500301/
关键词：
Tyrosine hydroxylase Stability Phosphorylation α-Synuclein

项目摘要

In a series of earlier experiments we examined mutated forms of human tyrosine hydroxylase type 1 (hTH1), which are more stable than wild-type hTH1, because they should be promising tools for the gene therapy of Parkinson's disease (PD). We recently reported the following observations: 1) a mutant hTH1 with a deletion of its N-terminus up to Ala^<52> was much more stable than wild-type hTH1 in mammalian cells; 2) the presence of a PEST motif (a proline, glutamate/aspartate, serine, and threonine motif), which confers rapid turnover of many short-lived regulatory proteins, was predicted for the N-terminus region. In that research, we proposed that the phenomenon that N-terminus-deleted hTH1 was more stable than wild-type hTH1 might be a straightforward result of the loss of the PEST motif (PEST-1, Met^1-Lys^<12>). Therefore, one of the main aims of this study was to clarify whether the PEST-1 motif was involved in determining the degradation rate of the hTH1 protein.In this research, we clarified that 14-3-3η protein is a poisible regulator of the quantity of hTH1 protein in neuronal cells and that the N-terminus of the enzyme up to Asp^<22> is an important sequence in order for 14-3-3η protein to play such a role. However, the precise mechanism by which the 14-3-34 protein exerts its effect on the hTH1 molecule still remains to be solved. It is noteworthy that α-synuclein, which is another ubiquitous cytoplasmic chaperone and one of the main components of Lewy bodies, shares physical and functional homology with 14-3-3 proteins (sharing over 40% homology). In addition, α-synuclein binds to 14-3-3 proteins. Therefore, we believe that the research to clarify the roles of ubiquitous cytoplasmic chaperones such as 14-3-3 and α-synuclein in the proteolytic system will provide a new focus to afford a better understanding of the intracellular stability of the hTH1 molecule concerning the neurodegenaration.

在一系列早期实验中，我们检测了人类 1 型酪氨酸羟化酶 (hTH1) 的突变形式，它们比野生型 hTH1 更稳定，因为它们应该是帕金森病 (PD) 基因治疗的有前途的工具。我们最近报道了以下观察结果：1）N端缺失至Ala^<52>的突变hTH1在哺乳动物细胞中比野生型hTH1更稳定； 2) 预测 N 末端区域存在 PEST 基序（脯氨酸、谷氨酸/天冬氨酸、丝氨酸和苏氨酸基序），该基序赋予许多短寿命调节蛋白的快速周转。在那项研究中，我们提出N端缺失的hTH1比野生型hTH1更稳定的现象可能是PEST基序（PEST-1，Met^1-Lys^<12>）丢失的直接结果。因此，本研究的主要目的之一是阐明PEST-1基序是否参与决定hTH1蛋白的降解率。在本研究中，我们阐明14-3-3η蛋白是神经元细胞中hTH1蛋白数量的潜在调节因子，并且该酶的N端直至Asp^<22>是14-3-3η蛋白的重要序列。蛋白质就起到这样的作用。然而，14-3-34蛋白对hTH1分子发挥作用的精确机制仍有待解决。值得注意的是，α-突触核蛋白是另一种普遍存在的细胞质伴侣，也是路易体的主要成分之一，与 14-3-3 蛋白具有物理和功能同源性（同源性超过 40%）。此外，α-突触核蛋白还与 14-3-3 蛋白结合。因此，我们相信，阐明蛋白水解系统中普遍存在的细胞质伴侣如14-3-3和α-突触核蛋白的作用的研究将为更好地理解hTH1分子在神经变性中的细胞内稳定性提供一个新的焦点。