Regulation of Ubiquitin Chain Topology

描述(由申请人提供)泛素(Ub)是一种调节蛋白质降解、定位和其他活性的重要信号分子。通常情况下，Ub分子的C末端通过E1/E2/E3反应级联反应共价连接到蛋白质底物的赖氨酸残基上，这种修饰被脱泛素酶(DUBS)逆转。通过第一个Ub分子的赖氨酸基和下一个Ub分子的C末端之间的连接，PolyUb链可以进一步组装在底物上。我们目前的蛋白质组学分析表明，Ub分子上的所有7个赖氨酸基都可以用于形成多聚Ub链，包括Lys6、Lys11、Lys27、Lys29、Lys33、Lys48和Lys63。我们认为，功能不同的PolyUb链的形成是泛素化和去泛素化的调节步骤。为了研究这些多聚Ub连接的功能，我们将首先开发一种质谱学技术来定量所有七个多Ub连接的丰度，然后研究DUB和多Ub链拓扑之间的催化专一性。此外，我们还将重点定义Lys11 PolyUb链的功能。我们的研究将有助于开发研究PolyUb链拓扑的通用蛋白质组学工具，并更好地了解PolyUb链的多样性和功能。

DESCRIPTION (PROVIDED BY APPLICANT) Ubiquitin (Ub) is an essential signal molecule regulating protein degradation, localization and other activities. Generally the C-terminus of the Ub molecule is covalently conjugated to lysine residues of protein substrates by the E1/E2/E3 reaction cascade, and the modification is reversed by the action of deubiquitinating enzymes (DUBs). PolyUb chains can be further assembled on the substrates by the linkage between lysine groups of the first Ub molecule and the C-terminus of the next. Our current proteomic analysis revealed that all seven lysine groups on the Ub molecule can be utilized for the formation of polyUb chains, including Lys6, Lys11, Lys27, Lys29, Lys33, Lys48, and Lys63. We propose that the formation of functionally distinct polyUb chains is a regulatory step for ubiquitination and deubiquitination. To examine the function of these polyUb linkages, we will first develop a mass spectrometry technology for quantifying the abundance of all seven polyUb linkages, and then study the catalytic specificity between DUBs and polyUb chain topology. Moreover, we will focus on defining the function of Lys11 polyUb chains. Our studies will lead to the development of general proteomic tools for polyUb chain topology and better understanding of the diversity and function of polyUb chains.