Molecular chaperone function in the biogenesis of large protein kinases

分子伴侣在大蛋白激酶生物发生中的功能

• 批准号: RGPIN-2014-04490
• 负责人: Stirling, Peter
• 金额: $ 2.91万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611067
• 关键词: Molecular; chaperone; function; biogenesis; large

Proteins are involved in essentially every cellular activity from the production of energy to cellular movement and the sensation of environmental cues. Proteins are long chains of amino acids, and in order to perform their wide variety of functions each protein chain must fold into the correct three-dimensional structure – the so-called ‘native’ state. Protein folding does not usually occur spontaneously in the cell and usually requires the assistance of factors called molecular chaperones. These chaperones guide and protect newly made proteins as they transition from a linear chain to a complex three-dimensional structure. Some chaperones help many different proteins, while others are very specific to the folding of only a few proteins. The proposed studies focus on the folding of several related proteins called PI3-kinase related kinases (PIKKs). PIKKs perform important cellular signaling functions ranging from detection of nutrients to detection of stress and DNA damage. The fundamental nature of PIKK function is supported by the fact that they have been widely conserved during evolution and have similar functions in organisms as distantly related as yeast and humans. PIKKs are also implicated in several human diseases, most notably cancer, where PIKK mutations are associated with tumour predisposition. PIKKs are very large proteins and require several specific molecular chaperones to fold into their native state. PIKK folding is assisted by chaperones called TTT and R2TP, so named for their protein components (TTT = Tel2-Tti1-Tti2 and R2TP = Rvb1-Rvb2-Tah1-Pih1). There is relatively little known about how TTT interacts with PIKKs and how it co-operates with R2TP. The proposed research will directly address how TTT subunits bind to one another, how TTT binds to PIKKs, whether this binding occurs before, after or simultaneously with R2TP and how the process is regulated. This research will first examine TTT function in yeast, and will use the insights gained to perform validation experiments in more complex mammalian cell systems. Finally, the research program will move toward exploring the consequences for TTT binding of naturally occurring PIKK variants associated with human disease. The proposed studies will define the molecular events that control the folding and assembly of PIKKs. This will provide new insights into the folding of large proteins and describe the mechanisms by which protein folding is a key regulatory step controlling the function of all the fundamental cellular activities orchestrated by PIKKs. In addition to these basic insights, the knowledge gained could have significant implications for understanding PIKK mutations associated with human disorders and cancer.

蛋白质基本上参与每一种细胞活动，从能量的产生到细胞运动和环境线索的感觉。蛋白质是由氨基酸组成的长链，为了发挥其广泛的功能，每条蛋白质链必须折叠成正确的三维结构-所谓的“天然”状态。蛋白质折叠通常不会在细胞中自发发生，通常需要分子伴侣的帮助。这些分子伴侣引导和保护新产生的蛋白质，因为它们从线性链过渡到复杂的三维结构。一些分子伴侣帮助许多不同的蛋白质，而另一些分子伴侣仅对少数蛋白质的折叠非常特异。拟议的研究集中在几个相关蛋白质的折叠称为PI 3-激酶相关激酶（PIKKs）。PIKK执行重要的细胞信号传导功能，从检测营养物质到检测应激和DNA损伤。PIKK功能的基本性质得到了以下事实的支持：它们在进化过程中被广泛保守，并且在酵母和人类等远亲生物中具有相似的功能。PIKK还涉及几种人类疾病，最值得注意的是癌症，其中PIKK突变与肿瘤易感性相关。 PIKK是非常大的蛋白质，需要几种特定的分子伴侣才能折叠成它们的天然状态。PIKK折叠由称为TTT和R2 TP的分子伴侣辅助，TTT = Tel 2-Tti 1-Tti 2，R2 TP = Rvb 1-Rvb 2-Tah 1-Pih 1。关于TTT如何与PIKK相互作用以及它如何与R2 TP合作，人们知之甚少。这项研究将直接解决TTT亚基如何相互结合，TTT如何与PIKKs结合，这种结合是否发生在R2 TP之前，之后或同时发生，以及该过程如何调节。这项研究将首先研究TTT在酵母中的功能，并将利用所获得的见解在更复杂的哺乳动物细胞系统中进行验证实验。最后，该研究计划将转向探索与人类疾病相关的自然发生的PIKK变体的TTT结合的后果。 拟议的研究将定义控制PIKK折叠和组装的分子事件。这将为大型蛋白质的折叠提供新的见解，并描述蛋白质折叠是控制PIKK协调的所有基本细胞活动功能的关键调控步骤的机制。在 除了这些基本的见解，所获得的知识可能对理解与人类疾病和癌症相关的PIKK突变具有重要意义。