The mechanism of nuclear autophagy

项目摘要 在过去的10年里，溶酶体介导的降解途径巨型自噬得到了显著的重视。 在衰老相关疾病和延长寿命的研究中。巨噬细胞自噬是一种重要的细胞 负责消除胞浆蛋白、脂类和细胞器的途径，因此，场 侧重于巨型自噬在清除蛋白质聚集体或功能失调的细胞器(如 线粒体)，特异性地聚集在细胞质中。然而，蛋白质的积累和 细胞器功能障碍发生在细胞核内，显然不受细胞质的影响。 双膜核膜的突起。此外，老龄化和核能之间的联系 包膜结构缺陷正在出现，包括由基因突变引起的核包膜 包膜支架层板和相关的完整内核膜蛋白。细胞如何做出反应 对这些核侮辱还没有很好的理解，但有新的证据表明，核组件 包膜和核受到依赖于宏观自噬的翻转。因此，很明显，我们必须 重新将注意力集中在核质量控制是如何执行的，特别是在机制上(S) 控制细胞质自噬小体中的核内容周转。因此，在本提案中，我们将重点放在 细胞质自噬机制和核膜重塑的基本问题 协调一致。使用酿酒酵母，其中驱动核自噬的分子机制的发现是 最成熟的，并且我们已经生成了大量的初步和最近发布的数据，我们将测试一个 令人兴奋的“由外而内”的亲核模型。该模型调用了一种新型的跨肾小桥 核膜被膜，并将胞浆连接到细胞核。因此，这项提案将充分定义 构成这一亲核途径的分子成分，并将这些因子置于超微结构 时间线。然后，这一途径的元件将使用完全工程的体外系统重新构建，以便 共同提供关键的分子洞察力，了解需要移除的关键膜重构事件 核内容，同时保持核的完整性。随着这个项目的完成，我们将进一步推动我们的 机械地理解一个关键的、被低估的宏观自噬过程，并打开大门来定义如何 核自噬可以影响衰老受损的蛋白稳定。

Project Summary Over the last 10 years, the lysosome-mediated degradation pathway macroautophagy has gained prominence in the study of aging-related disorders and extension of lifespan. Macroautophagy is an essential cellular pathway responsible for the elimination of cytosolic proteins, lipids and organelles, and as such, the field has focused upon the role of macroautophagy in clearing protein aggregates or dysfunctional organelles (such as mitochondria) that specifically accumulate in the cytoplasm. Increasingly however, protein accumulation and organelle dysfunction are observed to occur within the nucleus, apparently shielded from cytoplasmic processes by the double-membraned nuclear envelope. Furthermore, links between aging and nuclear envelope structural defects are emerging, including nuclear envelopathies caused by mutations in the envelope scaffolding lamins and associated integral inner nuclear membrane proteins. How the cell responds to these nuclear insults is not well understood, but there is emerging evidence that components of the nuclear envelope and the nucleus are subject to macroautophagy-dependent turnover. Thus, it is clear that we must refocus our attention on how nuclear quality control is executed and specifically on the mechanism(s) that governs nuclear content turnover in cytoplasmic autophagosomes. Thus, in this proposal, we focus on the fundamental question of how cytoplasmic autophagy machinery and nuclear envelope remodeling are coordinated. Using S. cerevisiae, where discovery of the molecular machinery driving nuclear autophagy is the most mature and where we have generated substantial preliminary and recently published data, we will test an exciting “outside-in” model of nucleophagy. This model invokes a novel translumenal bridge that spans the nuclear envelope membranes and connects the cytosol to the nucleus. This proposal will thus fully define the molecular components that make up this nucleophagy pathway and place these factors within an ultrastructural timeline. Elements of this pathway will then be reconstituted using fully engineered in vitro systems in order to collectively provide critical molecular insight into the key membrane remodeling events necessary to remove nuclear contents while maintaining nuclear integrity. With the completion of this project, we will further our mechanistic understanding of a key underappreciated macroautophagic process and open doors to define how nuclear autophagy can impact aging-impaired proteostasis.