Mint2以“打开—闭合”构象变化来调节APP的代谢

发布时间：2018-06-01 23:05

本文选题：阿尔茨海默病(Alzheimer + 　；参考：《南开大学》2013年博士论文

【摘要】：阿尔兹海默病(Alzheimer's disease, AD)是一种神经退化性失调,困扰着全球数百万的老龄人。本文基于晶体结构及后续的生化和功能手段研究了在AD发病机制中起着重要作用的两个蛋白Mint2和amyloid-β protein precursor (APP)。 Aβ的沉积是AD病的一个重要标志,它的产生来自APP有序分解。APP的转运和代谢的调节取决于结合到APP胞内末端的蛋白,这其中就包括Mint蛋白家族。Mint蛋白家族,是一个含多个蛋白-蛋白相互作用结构域的支架蛋白家族。Mint蛋白家族包括一个变化的氮端区域和一个保守性很高的碳端区域,其碳端区域包含一个重要的phosphotyrosine-binding (PTB)结构域,一对串联排列的PDZ结构域和最末端的C端(之后简称PPC)。通过这些结构域,Mints介导组装成功能各异的蛋白复合体,最引入注目的是能够调节APP的代谢过程和参与amyloid-β多肽(Aβ)的生成。Mint蛋白家族的PTB结构域能结合APP的YENPTY模序。但是APP动态结合Mint2的分子机制还不清楚。本文报道了结合及没有结合APP多肽的Mint2-PPC的两个晶体结构,其分辨率分别为3.3A和2.7A。这些结构表明没有结合APP多肽的Mint2-PPC以“闭合”的构象存在,在这个状态中ARM结构域盖住了PTB结构域的APP多肽结合口袋。而与之完全相反的是,结合APP多肽的Mint2-PPC以“打开”的构象存在,此时ARM结构域彻底从结合多肽处旋转开来。体内和体外实验证明了控制Mint2“打开—闭合”构象变化的不同突变体动态调节APP代谢。我们的实验结果揭示了PTB结构域一种崭新的“打开—闭合”构象变化动态地结合它的多肽底物的机制。此外,这种构象变化可能代表Mint蛋白家族调节APP蛋白家族的一种普遍模式,为AD疾病的治疗提供有用的信息。
[Abstract]:Alzheimer's disease (ADD) is a neurodegenerative disorder that affects millions of elderly people worldwide. Two proteins, Mint2 and amyloid- 尾 protein precursor, which play an important role in the pathogenesis of AD, were studied based on crystal structure and subsequent biochemical and functional methods. The deposition of A 尾 is an important marker of AD disease. Its production comes from the regulation of the transport and metabolism of APP. App depends on the proteins binding to the intracellular end of APP, including the Mint protein family. A family of scaffold proteins containing multiple protein-protein interaction domains. Mint protein family consists of a variable nitrogen terminal region and a highly conserved carbon terminal region, the carbon terminal region of which contains an important phosphotyrosine-binding domain. A pair of PDZ domains arranged in series and the terminal C terminal. These domains were used to mediate the assembly of protein complexes with different functions. The most striking one was the ability to regulate the metabolic process of APP and to participate in the production of amyloid- 尾 polypeptide A 尾. The PTB domain of the Mint protein family could bind to the YENPTY motif of APP. However, the molecular mechanism of APP binding to Mint2 is unclear. In this paper, we report two crystal structures of Mint2-PPC with and without binding to APP polypeptides, the resolution of which are 3.3A and 2.7 A. These structures indicate that Mint2-PPC with no binding to APP polypeptide exists in a "closed" conformation, in which the ARM domain covers the APP polypeptide binding pocket of the PTB domain. On the contrary, the Mint2-PPC binding to APP peptide exists in the "open" conformation, and the ARM domain rotates completely from the binding polypeptide. In vivo and in vitro experiments demonstrated that different mutants that control the conformation of Mint2 "open-close" regulate APP metabolism dynamically. Our experimental results reveal the mechanism of a new "open-close" conformation change in the PTB domain that dynamically binds to its polypeptide substrate. In addition, this conformational change may represent a common pattern of Mint protein family regulating APP protein family and provide useful information for the treatment of AD disease.
【学位授予单位】：南开大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R749.16

【相似文献】