Deciphering the ubiquitin code in stress signaling and membrane trafficking

项目摘要 泛素是一种76个氨基酸的肽，其可以与底物共价缀合以改变细胞中蛋白质的命运。 调节蛋白质的降解、运输、亚细胞定位和蛋白质-蛋白质间的相互作用 交互.由于其多功能性，泛素调节许多基本的细胞过程， 失调与从神经变性到癌症的许多人类疾病有关。泛素 网络包括结合酶和去结合酶以及由泛素组成的效应子途径 指导泛素修饰底物命运的结合蛋白。所有这些因素共同作用， “写”、“读”和“编辑”遍在蛋白代码--它最终由不同长度的遍在蛋白聚合物组成 以及决定哪些效应器通路参与的拓扑结构。在这里，我们描述了两个主要的研究 方向，这将导致更深入地了解泛素代码，以及它如何调节不同的细胞 功能，包括压力信号和膜运输。第一个研究方向将解决如何 泛素在Ser 57位置的磷酸化调节酵母和人细胞中的应激反应。的 建议的研究将建立在我们最近发现的一小群丝氨酸57泛素激酶的基础上，这些激酶在 酵母到人类，并将包括遗传，生物化学和蛋白质组学的方法。具体来说，我们将 确定这些激酶和泛素的Ser 57磷酸化如何促进细胞应激反应， 我们将讨论泛素磷酸化如何改变其相互作用的概况和参与效应 途径。这项研究将为泛素的生物学提供变革性的新见解， 蛋白质稳态第二个研究方向将解决人类葡萄糖转运蛋白是如何调节的， 泛素修饰和内吞运输。GLUT家族的葡萄糖转运蛋白是葡萄糖代谢的关键调节因子。 细胞葡萄糖稳态，但其运输和质量控制的调节仍然很差 表征了在这里，我们描述了我们最近的研究结果，即GLUT 1内吞 运输受特定的泛素修饰调节。这些研究对细胞生物学具有重要意义。 葡萄糖稳态和人类疾病，包括GLUT 1缺乏综合征和许多类型的癌症。 总之，这些研究方向将导致更深入地了解泛素代码，膜 真核细胞中的运输和应激反应。

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.