中国神经再生研究(英文版)

中国神经再生研究(英文版) ›› 2013, Vol. 8 ›› Issue (11): 991-999.doi: 10.3969/j.issn.1673-5374.2013.11.004

• 原著:退行性病与再生 • 上一篇    下一篇

CUTA与β-分泌酶相互作用减少淀粉样前体蛋白的产生

  

  • 收稿日期:2012-10-08 修回日期:2013-02-27 出版日期:2013-04-15 发布日期:2013-04-15

Divalent cation tolerance protein binds to β-secretase and inhibits the processing of amyloid precursor protein

Runzhong Liu1, Haibo Hou1, Xuelian Yi1, Shanwen Wu1, Huan Zeng2   

  1. 1 State Key Laboratory of Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian Province, China
    2 Xiamen Maternal and Child Health Hospital, Xiamen 361003, Fujian Province, China
  • Received:2012-10-08 Revised:2013-02-27 Online:2013-04-15 Published:2013-04-15
  • Contact: Runzhong Liu☆, Ph.D., Associate professor, State Key Laboratory of Cellular Stress Biology, Department of Biomedical Sciences, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian Province, China, liurz@xmu.edu.cn.
  • About author:Runzhong Liu and Haibo Hou contributed equally to this work.

PDF

717

摘要：

淀粉样蛋白（β-amyloid, Aβ）沉积在神经元胞外是阿尔茨海默病（Alzheimer disease，AD）的重要病理特征之一。淀粉样蛋白是由淀粉样前体蛋白（amyloid precursor protein, APP）经β-分泌酶（beta-site APP-cleaving enzyme, BACE）和γ-分泌酶水解产生的，因此β-分泌酶在阿尔茨海默病的形成过程中发挥重要作用。为了进一步研究β-分泌酶的作用机制，实验以β-分泌酶胞内段构建诱饵蛋白用酵母双杂交方法筛选与之相互作用的蛋白。结果得到了二价阳离子耐受蛋白（divalent cation tolerant protein，CUTA）的阳性克隆，β-半乳糖苷酶实验表明二价阳离子耐受蛋白和β-分泌酶胞内片段存在相互作用。我们构建了两者全长基因的表达载体，并证明二者在哺乳动物细胞中同样可以相互作用。二价阳离子耐受蛋白可能涉及铜的代谢动力学及乙酰胆碱酯酶（AchE）的膜锚定，而铜的代谢失衡和乙酰胆碱酯酶水平与阿尔茨海默病发病密切相关。免疫沉淀试验结果表明，在N2a细胞中，外源性的二价阳离子耐受蛋白可与内源性的β-分泌酶相互作用；而过表达二价阳离子耐受蛋白并不影响β-分泌酶的水平，但会导致淀粉样前体蛋白水平的升高，同时淀粉样前体蛋白切割产物淀粉样前体蛋白羧基端片段的减少。表明二价阳离子耐受蛋白可能负调节β-分泌酶的功能，从而对阿尔茨海默病的病理发生起保护作用。我们的实验结果为β-分泌酶生物学功能和阿尔茨海默病发病机制的阐明提供了新的内容。

关键词: 神经再生, 神经退行性疾病, 阿尔茨海默病, 淀粉样蛋白, β-分泌酶, 淀粉样前体蛋白, 二价阳离子耐受蛋白, 相互作用, APP-CTF, 免疫印迹, 酵母双杂交方法

Abstract:

The deposition of amyloid-beta is a pathological hallmark of Alzheimer’s disease. Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase (beta-site amyloid precursor protein-cleaving enzyme 1) and γ-secretase. To further elucidate the roles of beta-site amyloid precursor protein-cleaving enzyme 1 in the development of Alzheimer’s disease, a yeast two-hybrid system was used to screen a human embryonic brain cDNA library for proteins directly interacting with the intracellular domain of beta-site amyloid precursor protein-cleaving enzyme 1. A potential beta-site amyloid precursor protein-cleaving enzyme 1- interacting protein identified from the positive clones was divalent cation tolerance protein. Immunoprecipitation studies in the neuroblastoma cell line N2a showed that exogenous divalent cation tolerance protein interacts with endogenous beta-site amyloid precursor protein-cleaving enzyme 1. The overexpression of divalent cation tolerance protein did not affect beta-site amyloid precursor protein-cleaving enzyme 1 protein levels, but led to increased amyloid precursor protein levels in N2a/APP695 cells, with a concomitant reduction in the processing product amyloid precursor protein C-terminal fragment, indicating that divalent cation tolerance protein inhibits the processing of amyloid precursor protein. Our experimental findings suggest that divalent cation tolerance protein negatively regulates the function of beta-site amyloid precursor protein-cleaving enzyme 1. Thus, divalent cation tolerance protein could play a protective role in Alzheimer’s disease.