Risseeuw Eddy P, Daskalchuk Timothy E, Banks Travis W, Liu Enwu, Cotelesage Julian, Hellmann Hanjo, Estelle Mark, Somers David E, Crosby William L
Gene Expression Group, NRC Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK, Canada S7N-0W9.
Plant J. 2003 Jun;34(6):753-67. doi: 10.1046/j.1365-313x.2003.01768.x.
Ubiquitin E3 ligases are a diverse family of protein complexes that mediate the ubiquitination and subsequent proteolytic turnover of proteins in a highly specific manner. Among the several classes of ubiquitin E3 ligases, the Skp1-Cullin-F-box (SCF) class is generally comprised of three 'core' subunits: Skp1 and Cullin, plus at least one F-box protein (FBP) subunit that imparts specificity for the ubiquitination of selected target proteins. Recent genetic and biochemical evidence in Arabidopsis thaliana suggests that post-translational turnover of proteins mediated by SCF complexes is important for the regulation of diverse developmental and environmental response pathways. In this report, we extend upon a previous annotation of the Arabidopsis Skp1-like (ASK) and FBP gene families to include the Cullin family of proteins. Analysis of the protein interaction profiles involving the products of all three gene families suggests a functional distinction between ASK proteins in that selected members of the protein family interact generally while others interact more specifically with members of the F-box protein family. Analysis of the interaction of Cullins with FBPs indicates that CUL1 and CUL2, but not CUL3A, persist as components of selected SCF complexes, suggesting some degree of functional specialization for these proteins. Yeast two-hybrid analyses also revealed binary protein interactions between selected members of the FBP family in Arabidopsis. These and related results are discussed in terms of their implications for subunit composition, stoichiometry and functional diversity of SCF complexes in Arabidopsis.
泛素E3连接酶是一个多样化的蛋白质复合物家族，它们以高度特异性的方式介导蛋白质的泛素化以及随后的蛋白水解周转。在几类泛素E3连接酶中，Skp1 - Cullin - F盒（SCF）类通常由三个“核心”亚基组成：Skp1和Cullin，加上至少一个F盒蛋白（FBP）亚基，该亚基赋予对选定靶蛋白泛素化的特异性。拟南芥最近的遗传和生化证据表明，由SCF复合物介导的蛋白质翻译后周转对于多种发育和环境响应途径的调节很重要。在本报告中，我们扩展了之前对拟南芥Skp1样（ASK）和FBP基因家族的注释，以纳入Cullin蛋白家族。对涉及所有三个基因家族产物的蛋白质相互作用谱的分析表明，ASK蛋白之间存在功能差异，即该蛋白家族的选定成员通常相互作用，而其他成员则更特异性地与F盒蛋白家族的成员相互作用。对Cullins与FBPs相互作用的分析表明，CUL1和CUL2，而不是CUL3A，作为选定SCF复合物的组分持续存在，这表明这些蛋白质存在一定程度的功能特化。酵母双杂交分析还揭示了拟南芥中FBP家族选定成员之间的二元蛋白质相互作用。我们根据这些结果及其对拟南芥中SCF复合物的亚基组成、化学计量和功能多样性的影响进行了讨论。
