Functional analysis of SCF ubiquitin ligase complexes

泛素介导的蛋白质降解在真核生物调控转录、DNA复制、细胞周期、分化以及对各种外源刺激的反应中，在许多细胞过程的信号级联中起着重要的作用。泛素化的特异性是由不同类型的泛素连接酶介导的。SCF复合体(Skp1/Cullin/F-box蛋白)是真核生物中最重要的泛素连接酶类之一，F-box蛋白介导对靶蛋白的特异性识别。由于在所有已鉴定的拟南芥基因中，约有2.5%编码SCF复合体的可能成分，这类泛素连接酶可能在调节高等植物中特定蛋白质的降解方面发挥着突出的作用。在拟议的研究项目中，我们希望分析携带F-box蛋白某个亚家族成员的SCF复合体的功能、组成和靶点。这些F-box蛋白与EID1同源，EID1是我们组鉴定的依赖光敏色素A的光信号的重要组成部分。此外，我们想要阐明高可变F-box结构域与核心复合体成分之间相互作用的特异性。

Ubiquitin-mediated degradation of proteins by the 26S proteasome plays an important role in signaling cascades of many cellular processes in all eukaryotes regulation transcription, DNA replication, cell cycle, differentiation and responses to various exogenous stimuli. The specificity of the ubiquitylation is mediated by different classes of ubiquitin ligases. SCF complexes (for Skp1/Cullin/F-box protein) form one of the most important classes of ubiquitin ligases in eukaryotes, whereby the F-box proteins mediate the specific recognition of target proteins. Because about 2.5 % of all identified Arabidopsis genes encode for putative components of SCF complexes, this class of ubiquitin ligases probably plays an outstanding role in regulating specific protein degradation in higher plants. In the proposed research projects, we want to analyze the function, composition and targets of SCF complexes which carry a member of a certain subfamily of F-box proteins. These F-box proteins show homology to EID1, an important component of phytochrome A-dependent light signaling that was identified from our group. Furthermore, we want to elucidate the specificity of the interaction between the highly variable F-box domains and the components of the core complexes.