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核心组成部分，估计折叠真核蛋白质组的5-10%。TRiC组装成一个环状的低聚物复合物，由两个堆叠的环组成，每个环含有8个不同的亚基。这些环形成一个中心空腔，在那里未折叠的蛋白质以ATP依赖的方式结合和折叠。一个基本问题仍然存在：TRiC如何识别和折叠真核蛋白的不同子集？我们假设异质寡聚复合物中的每个亚基在底物特异性上有所不同。然而，这一假设仍然未经检验，因为对trici -底物相互作用的性质知之甚少。本提案的目标是确定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底物的基元如何与单个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。这项工作将对开发新的治疗方法来改善与蛋白质错误折叠相关的疾病具有重要意义。

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.