The SMYD lysine methyltransferase Set6 in signaling and proteostasis

项目总结 蛋白质稳态，或蛋白质稳态，是通过一个受调节的翻译网络实现的 机械、分子伴侣和蛋白质降解因子，它们的功能是维持 细胞蛋白质在折叠、可溶、非聚集状态下的丰度。经济状况的恶化 蛋白平衡网络是细胞老化的标志，是许多相关疾病的基础 随着年龄的增长。蛋白质平衡网络中调节因子的一个关键机制是它们的后 翻译修饰，包括赖氨酸残基的甲基化。SMYD赖氨酸家族 甲基转移酶已被证明在不同的系统中与分子伴侣相互作用， 据报道，有许多赖氨酸甲基化位点存在于促进 蛋白质平衡。然而，我们对SMYD靶向的甲基赖氨酸底物的了解 甲基转移酶及其与蛋白平衡网络的功能相互作用仍然非常 有限的。拟议工作的主要目标是利用蛋白质组和分子工具 在模型体系中确定酿酒酵母SMYD的底物 酶Set6，一种在很大程度上没有特征的蛋白质，并确定其调节的分子功能 蛋白质平衡网络。在AIM I中，我们将使用高分辨率质谱学来识别 Set6全蛋白质组靶标及赖氨酸的分子和生化特性研究 新发现的底物上的甲基化。在AIM II中，我们将使用分子和遗传工具 明确Set6在与蛋白质平衡网络相互作用和调节中的作用，以防止 未折叠蛋白质的积累。总的来说，这项工作将整合蛋白质组学和基因分析 为了增进我们对SMYD家族赖氨酸之间的机制联系的理解 甲基转移酶和分子伴侣。我们期待这项工作为我们提供新的见解 对蛋白质稳定至关重要的调控机制，这可能有助于揭示新的靶点 对蛋白质错误折叠和聚集相关疾病的治疗干预。 此外，这些研究还将开发一种具有良好特性的遗传模型系统 剖析SMYD酶促进蛋白平衡和蛋白质平衡的分子机制 确定它们的操作如何可以防止与衰老相关的病理。

PROJECT SUMMARY Protein homeostasis, or proteostasis, is achieved through a regulated network of the translational machinery, molecular chaperones, and protein degradation factors, which function to maintain the abundance of the cell’s proteins in folded, soluble, non-aggregated states. Deterioration of the proteostasis network is a hallmark of aging cells and underlies numerous diseases associated with aging. A key mechanism regulating factors within the proteostasis network is their post- translational modification, including methylation at lysine residues. The SMYD family of lysine methyltransferases has been shown to interact with molecular chaperones in diverse systems, and there are numerous reported lysine methylation sites on factors that contribute to proteostasis. However, our knowledge of the methyl-lysine substrates targeted by SMYD methyltransferases and their functional interactions with the proteostasis network is still very limited. The primary objective of the proposed work is to leverage proteomic and molecular tools in the model system Saccharomyces cereviasie to define the substrates for the yeast SMYD enzyme Set6, a largely uncharacterized protein, and determine its molecular function in regulating the proteostasis network. In Aim I, we will use high-resolution mass spectrometry to identify targets of Set6 proteome-wide and perform molecular and biochemical characterization of lysine methylation on the newly-identified substrates. In Aim II, we will use molecular and genetic tools to define the role of Set6 in interacting with and regulating the proteostasis network to prevent the accumulation of unfolded proteins. In total, this work will integrate proteomic and genetic analyses to advance our understanding of the mechanistic links between the SMYD family lysine methyltransferases and molecular chaperones. We expect this work to provide new insights into regulatory mechanisms critical to proteostasis, which may shed light on new targets for therapeutic interventions into diseases associated with protein misfolding and aggregation. Furthermore, these studies will also develop a well-characterized, genetic model system for dissecting the molecular mechanisms by which SMYD enzymes contribute to proteostasis and determining how their manipulation may prevent aging-associated pathologies.