Molecular Mechanism and In Vivo Study of ER Associated Degradation

描述（由申请方提供）：蛋白质质量控制需要去除错误折叠的蛋白质。如果错误折叠的蛋白质持续存在，这种错配的积累导致未折叠蛋白质反应（UPR）的激活，最终对细胞和生物体造成病理后果。不能在ER中折叠的蛋白质，无论是腔蛋白还是膜蛋白，通常被反向易位或“错位”到胞质溶胶中进行降解。这种错位在很大程度上是泛素依赖性的，错误折叠的胞质蛋白的降解也是如此。该项目的总体目标是研究ER相关降解（ERAD）的机制，以及该过程的破坏如何导致或成为各种蛋白质错误折叠疾病发展的重要因素。为了实现这一目标，新的捕获和释放探针将与光交联剂相结合，以确定新的组件参与错位：在体内泛素受体的ERAD泛素结合酶Ubc6e和Ubc6e的体内相互作用的合作伙伴。目前很难将内质网应激调控的研究扩展到生物体水平。Ploegh实验室已经开发出工具，现在允许我们以无毒的方式阻止ER脱位过程，这种方法将被利用并扩展到两种新的体内小鼠模型。新的位错成分的识别将是我们对ERAD机械基础知识的重要扩展。由于许多疾病都归因于错误折叠蛋白质的积累，因此所提出的实验与许多疾病有关。 公共卫生相关性：错误折叠蛋白质在细胞中的积累是许多疾病发展的重要因素。我提出的项目将有助于阐明细胞对这种异常蛋白质的积累和处理机制的反应。

DESCRIPTION (provided by applicant): Protein quality control entails the removal of misfolded proteins. Accumulation of such misfits leads to activation of the unfolded protein response (UPR) with eventual pathological consequences to the cell and organism, should misfolded proteins persist. Proteins, either luminal or membrane-disposed, that fail to fold in the ER are often retro-translocated or 'dislocated' into the cytosol for degradation. This dislocation is to a large extent ubiquitin- dependent, as is the degradation of misfolded cytosolic proteins. The overall goal of the project is to study the mechanism of ER associated degradation (ERAD) and how disruption of this process leads to, or is an important factor in, the development of various protein misfolding diseases. To achieve this goal, novel catch-and-release probes will be applied in combination with photo-crosslinkers to identify new components involved in dislocation: in vivo ubiquitin acceptors of the ERAD ubiquitinating conjugating enzyme Ubc6e and in vivo interaction partners of Ubc6e. It is currently difficult to extend the study of ER stress control to the organismal level. The Ploegh lab has developed tools that now allow us to block the ER dislocation process in a non-toxic manner, an approach that will be exploited and extended to two new in vivo mouse models. Identification of novel dislocation components will be an important extension of our basic knowledge of ERAD machinery. Because many diseases have been attributed to the accumulation of misfolded proteins, the proposed experiments are relevant to numerous diseases. PUBLIC HEALTH RELEVANCE: The accumulation of misfolded proteins in cells is an important factor in the development of many diseases. My proposed project will aid in elucidating the cellular response to the accumulation and the disposal mechanism of such aberrant proteins.