Deciphering the ubiquitin code in stress signaling and membrane trafficking

项目摘要 泛素是一种76个氨基酸的多肽，可以共价连接到底物上来改变蛋白质的命运。 调节蛋白质降解、运输、亚细胞定位和蛋白质-蛋白质的多种途径 互动。由于其多功能性，泛素调节许多基本的细胞过程，其 调节失调与许多人类疾病有关，从神经退化到癌症。泛素 网络包括结合酶和去结合酶以及由泛素组成的效应通路 决定泛素修饰底物命运的结合蛋白。所有这些元素共同作用于 “写”、“读”和“编辑”泛素编码--它最终由不同长度的泛素聚合物组成 以及确定哪些效应器路径被占用的拓扑结构。在这里，我们描述两个主要的研究 将导致对泛素密码及其如何调节不同细胞的更深层次理解的方向 功能，包括应激信号和膜运输。第一个研究方向将解决如何 Ser57位泛素的磷酸化调节酵母和人类细胞的应激反应。这个 拟议的研究将建立在我们最近发现的一小群Ser57泛素激酶的基础上，这些泛蛋白激酶从 酵母对人类的影响，将包括遗传、生化和蛋白质组学方法。具体来说，我们将 确定这些激酶和泛素的Ser57磷酸化如何促进细胞应激反应， 我们将解决泛素磷酸化如何改变其相互作用模式和与效应器的接触 小路。这项研究将为泛素和泛素的生物学提供变革性的新见解 蛋白质平衡。第二个研究方向将解决人类葡萄糖转运蛋白是如何通过 泛素修饰和胞内转运。过剩家族的葡萄糖转运蛋白是关键的调节因子 细胞内葡萄糖稳态，但对它们的运输和质量控制的监管仍然很差 特色化的。在这里，我们描述了基于我们最近的发现的研究路线，GLUT1内吞 贩运受到特定泛素修饰的监管。这些研究对细胞 葡萄糖动态平衡与人类疾病，包括GLUT1缺乏综合症和多种癌症。 总之，这些研究方向将导致对泛素密码-膜的更深层次的理解 运输，以及真核细胞中的应激反应。

Project Summary Ubiquitin is a 76 amino acid peptide that can be covalently conjugated to substrates to alter protein fate in diverse ways, regulating protein degradation, trafficking, subcellular localization and protein-protein interactions. Given its versatility, ubiquitin regulates many fundamental cellular processes, and its dysregulation is associated with many human diseases ranging from neurodegeneration to cancer. Ubiquitin networks include conjugating and deconjugating enzymes as well as effector pathways comprised of ubiquitin binding proteins that direct the fate of ubiquitin-modified substrates. All of these elements work together to “write”, “read”, and “edit” the ubiquitin code – which ultimately consists of ubiquitin polymers of different lengths and topologies that determine which effector pathways are engaged. Here, we describe two main research directions that will result in a deeper understanding of the ubiquitin code and how it regulates diverse cellular functions, including stress signaling and membrane trafficking. The first research direction will address how phosphorylation of ubiquitin at the Ser57 position regulates stress responses in yeast and human cells. The proposed studies will build on our recent discovery of a small group of Ser57 ubiquitin kinases conserved from yeast to humans and will include genetic, biochemical, and proteomic approaches. Specifically, we will determine how these kinases and Ser57 phosphorylation of ubiquitin contribute to the cellular stress response, and we will address how ubiquitin phosphorylation alters its interaction profile and engagement with effector pathways. This research will contribute transformative new insights into the biology of ubiquitin and proteostasis. The second research direction will address how human glucose transporters are regulated by ubiquitin modification and endocytic trafficking. Glucose transporters of the GLUT family are key regulators of cellular glucose homeostasis, and yet regulation of their trafficking and quality control remain poorly characterized. Here, we describe lines of investigation based on our recent findings that GLUT1 endocytic trafficking is regulated by specific ubiquitin modifications. These studies have important implications for cellular glucose homeostasis and human diseases including GLUT1 Deficiency Syndrome and many types of cancer. Together, these research directions will result in a deeper understanding of the ubiquitin code, membrane trafficking, and stress responses in eukaryotic cells.