The F-box subunit of the SCF E3 complex is encoded by a diverse superfamily of genes in Arabidopsis
The F-box subunit of the SCF E3 complex is encoded by a diverse superfamily of genes in Arabidopsis
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DOI：
10.1073/pnas.162339999
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发表时间：
2002-08-20
影响因子：
11.1
通讯作者：
Vierstra, RD
中科院分区：
文献类型：
--
作者：
Gagne, JM;Downes, BP;Vierstra, RD
泛素的共价结合是26S蛋白酶体在动植物中选择性降解蛋白质的重要决定因素。泛素化的特异性通常由泛素蛋白连接酶(或E3s)控制，它促进泛素转移到合适的靶点。SCF E3s是一种连接酶类型，由cullin1/cdc53、Rbx1/Roc1/Hrt1、Skp1和F-box蛋白四种蛋白组成。识别靶标的F-box蛋白通过一个约60-aa基序的简并N端称为F-box与复合体的Skp1组分结合。利用已发表的F-box作为查询，我们已经在拟南芥中鉴定出694个潜在的F-box基因，使该基因超家族成为目前已知的植物中最大的基因之一。大多数编码的蛋白质都含有C-末端到F-box的相互作用结构域，可能参与底物识别。F-box蛋白可以通过系统发育的方法划分为五个主要家族，这些家族还可以进一步组织成多个亚家族。亚家族的序列多样性表明许多F-box蛋白具有不同的功能和/或底物。所有主要家族的代表在酵母双杂交实验中与拟南芥Skp家族成员相互作用，支持将其归类为F-box蛋白。对一些人来说，对Skp的偏好是有限的，这表明SCF复合体的层次结构由不同的Skp/F-box蛋白对定义。总之，这些数据表明，拟南芥已经利用SCF复合体和泛素/26S蛋白酶体途径作为细胞调控的主要途径，植物中可能存在一系列不同的SCF靶标。
The covalent attachment of ubiquitin is an important determinant for selective protein degradation by the 26S proteasome in plants and animals. The specificity of ubiquitination is often controlled by ubiquitin-protein ligases (or E3s), which facilitate the transfer of ubiquitin to appropriate targets. One ligase type, the SCF E3s are composed of four proteins, cullin1/Cdc53, Rbx1/Roc1/Hrt1, Skp1, and an F-box protein. The F-box protein, which identifies the targets, binds to the Skp1 component of the complex through a degenerate N-terminal approximate to60-aa motif called the F-box. Using published F-boxes as queries, we have identified 694 potential F-box genes in Arabidopsis, making this gene superfamily one of the largest currently known in plants. Most of the encoded proteins contain interaction domains C-terminal to the F-box that presumably participate in substrate recognition. The F-box proteins can be classified via a phylogenetic approach into five major families, which can be further organized into multiple subfamilies. Sequence diversity within the subfamilies suggests that many F-box proteins have distinct functions and/or substrates. Representatives of all of the major families interact in yeast two-hybrid experiments with members of the Arabidopsis Skp family supporting their classification as F-box proteins. For some, a limited preference for Skps was observed, suggesting that a hierarchical organization of SCF complexes exists defined by distinct Skp/F-box protein pairs. Collectively, the data shows that Arabidopsis has exploited the SCF complex and the ubiquitin/26S proteasome pathway as a major route for cellular regulation and that a diverse array of SCF targets is likely present in plants.