Principles of substrate recognition by the eukaryotic chaperonin TRiC/CCT

描述（由申请人提供）：伴侣蛋白TRiC/CCT是真核蛋白质折叠机制的中心组分，估计折叠真核蛋白质组的5-10%。TRiC组装成环状寡聚复合物，其由两个堆叠的环组成，每个环含有八个不同的亚基。这些环产生一个中心空腔，未折叠的蛋白质以ATP依赖的方式结合和折叠。一个基本的问题仍然是：TRiC如何识别和折叠真核生物蛋白质的不同子集？我们假设异源寡聚复合物中的每个亚基在底物特异性上不同。然而，这一假设仍然未经检验，因为对TRiC-底物相互作用的性质知之甚少。该建议的目标是确定TRiC亚基中底物结合位点的位置，并阐明TRiC识别底物的机制。为此，我们将使用多学科方法来比较来自不同TRiC底物的基序如何与单个TRiC亚基结合。了解TRiC底物相互作用将揭示这种伴侣蛋白促进蛋白质折叠的机制。这项工作将有重要意义的发展新的治疗方法，以改善与蛋白质错误折叠相关的疾病。 公共卫生相关性：真核生物伴侣蛋白TRiC在许多重要的细胞真核蛋白的成熟中起着重要作用，并且其功能丧失与许多疾病如神经变性和癌症相关。系统解剖的结果伴侣蛋白底物结合相互作用的不同基板在拟议的实验中，将提供这些病理的治疗干预的方向。

DESCRIPTION (provided by applicant): The chaperonin TRiC/CCT is a central component of the eukaryotic protein folding machinery and is estimated to fold 5-10% of the eukaryotic proteome. TRiC assembles into a ring-shaped oligomeric complex that is comprised of two stacked rings each containing eight different subunits. The rings create a central cavity where unfolded proteins bind and fold in an ATP dependent manner. A fundamental question remains: how does TRiC recognize and fold a diverse subset of eukaryotic proteins? We hypothesize that each subunit in the hetero-oligomeric complex differs in substrate specificity. However, this hypothesis remains untested, as little is known about the nature of TRiC-substrate interactions. The goal of this proposal is to identify the location of the substrate binding sites in the TRiC subunits and elucidate the mechanisms underlying substrate recognition by TRiC. To this end, we will use a multidisciplinary approach to compare how motifs derived from different TRiC substrates bind to individual TRiC subunits. Understanding TRiC substrate interactions will reveal the mechanism by which this chaperonin facilitates protein folding. This work will have important implications for the development of novel therapeutic approaches to ameliorate diseases associated with protein misfolding. PUBLIC HEALTH RELEVANCE: The eukaryotic chaperonin TRiC plays a fundamental role in the maturation of many important cellular eukaryotic proteins, and its loss-of-function is associated with numerous diseases such as neurodegeneration and cancer. The results of systematically dissecting the chaperonin-substrate binding interactions for diverse substrates in the proposed experiments, will offer directions for therapeutic interventions in these pathologies.