The biological function of the COP9 signalosome-mediated deneddylation and deubiquitination

不同的泛素（Ub）家族（UbF）蛋白之间的相互作用，即所谓的UbF网络的组成部分，在项目过去的申请期间显著增加。很明显，例如Ub， Nedd8和SUMO通路并没有分开。相反，从细胞周期控制、DNA修复、发育到信号转导等基本细胞过程中，它们之间存在着许多相互作用的例子。在该项目的第一个申请期，我们专注于COP9信号体（CSN）介导的去醛化的表征。我们发现纯化的人红细胞CSN的去甲酰基化受到复合物磷酸化的影响。我们发现了CSN与脱羧酶1 （DEN1）的物理相互作用。我们的数据表明，CSN触发DEN1的Ub蛋白酶体系统（UPS）的核定位和降解。此外，我们开始生成条件Csn5D151N敲除蛋白和条件Usp15敲除小鼠品系。SPP 1365/2的主要目的是阐明CSN的去基化和去泛素化活性的生物学功能。我们将继续研究磷酸化和底物结合对中枢神经网络介导的去醛化的影响。我们期望从条件Csn5D151N敲除和Usp15敲除小鼠品系的特征中获得对生物学功能的大多数见解。

Publications on the interplay between different ubiquitin (Ub) family (UbF) proteins, constituents of the so called UbF network, have been significantly increased during the past application period of the project. It became clear that for example Ub, Nedd8 and SUMO pathways are not separated. In contrary, there exist many examples for their cross-talks in essential cellular processes ranging from cell cycle control, DNA repair, development to signal transduction. In the first application period of the project we have focused on the characterization of COP9 signalosome (CSN)-mediated deneddylation. We found that deneddylation by purified CSN from human red blood cells was affected by phosphorylation of the complex. We discovered a physical interaction of the CSN with the deneddylating enzyme 1 (DEN1). Our data show that the CSN triggers nuclear localization as well as degradation by the Ub proteasome system (UPS) of DEN1. In addition, we started to generate a conditional Csn5D151N knockin and a conditional Usp15 knockout mouse strain. Main objective of the forthcoming period of SPP 1365/2 will be the elucidation of the biological functions of the deneddylating and deubiquitinating activities of the CSN. We will continue to investigate the impact of phosphorylation and substrate binding on the CSN-mediated deneddylation. Most insights into the biological functions we expect from the characterization of the conditional Csn5D151N knockin and Usp15 knockout mouse strains.