中国神经再生研究(英文版) ›› 2016, Vol. 11 ›› Issue (2): 238-239.doi: 10.4103/1673-5374.177726

• 观点:退行性病与再生 • 上一篇    下一篇

内切蛋白酶裂解:触发神经退行性病的开关?

  

  • 收稿日期:2015-12-21 出版日期:2016-02-15 发布日期:2016-02-15

Endoproteolytic cleavage as a molecular switch regulating and diversifying prion protein function

Cathryn L. Haigh, Steven J. Collins   

  1. Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, Victoria, Australia
  • Received:2015-12-21 Online:2016-02-15 Published:2016-02-15
  • Contact: Cathryn L. Haigh, Ph.D. or Steven J. Collins, Ph.D., chaigh@unimelb.edu.au or stevenjc@unimelb.edu.au.

摘要:

朊病毒又称蛋白质侵染因子、毒朊或感染性蛋白质,是一类能侵染动物并在宿主细胞内复制的小分子无免疫性疏水蛋白质,是一类能引起哺乳动物和人的中枢神经系统病变的传染性病变因子。朊病毒蛋白通过错误折叠是广泛已知造成朊病毒疾病的原因之一,这是人类和动物传染性神经退行性疾病的诱因。尽管在这方面已有许多研究,但分配到朊病毒蛋白的功能,特别是在中枢神经系统中还没有得到有效定义。现提出的功能十分多变,包括信号传导、神经保护、神经发生、轴突形成、金属离子平衡、记忆形成和巩固以及昼夜节律。定义分配朊病毒蛋白非特异性功能之所以如此困难或许是因为它不只具有一个单独的功能。相反,它可能能够执行许多功能,并取决翻译后修饰条件各种途径的影响。近日,进一步裂解事件已被广泛用于研究表征。称为“伽马裂解”,该事件发生在C末端的结构域,因此产生的片段与α-和β-分裂具有非常不同的功能。文章深入研究了朊病毒蛋白的多功能性。

Abstract:

The prion protein (PrP), through misfolding, is widely known for its causative role in prion diseases, which are transmissible neurodegenerative diseases of humans and animals. There is still no defined function assigned to PrP, especially in the central nervous system, despite many studies in this area. Proposed functions are protean and include signal transduction, neuroprotection, neurogenesis, neuritogenesis, metal-ion homeostasis, memory formation and consolidation, as well as circadian rhythms. Part of the difficulty in assigning aspecific function to PrP could perhaps be that it does not have one single function. Instead it might be able to perform many functions and influence various pathways depending upon contextual post-translational modification. Recently a further cleavage event has been extensively characterised. Referred to as “gamma-cleavage”, this event occurs in the C-terminal structured domain and therefore produces fragments with very different features to both the α- and β-cleavages. A functional significance is yet to be assigned to this processing event, but its presence in multiple cells and tissues, and in disease, suggests that the fragments produced are likely toexert cellular effects distinct to that produced by the other PrP constitutive processing events. The precise cellular locations of the cleavage events and of the resulting fragments, whether processing occurs at the cell surface and whether N-terminal fragments act in cis or trans, the enzymes controlling these events, the membrane micro-milieuand dynamic rather than absolute cleavage levels may all potentially impact functional consequences. Until the various nuances of combined post-translational modifications of PrP coupled with cleavage events in different contexts and in different tissues are fully elucidated, PrP appears destined to remain an enigmatic “actor” playing in many apparent functional roles.