Dual E1 activation systems for ubiquitin differentially regulate E2 enzyme charging
Dual E1 activation systems for ubiquitin differentially regulate E2 enzyme charging
复制标题
DOI：
10.1038/nature05902
复制
发表时间：
2007-06-28
期刊：
影响因子：
64.8
通讯作者：
Harper, J. Wade
中科院分区：
文献类型：
--
作者：
Jin, Jianping;Li, Xue;Harper, J. Wade
通过E1-E2-E3级联用泛素或泛素样蛋白（UBL）修饰蛋白质控制许多信号传导网络（1-3）。泛素缀合涉及通过E1激活酶Ube 1（酵母中的Uba 1）对泛素羧基末端羧酸进行腺苷酸化和硫酯化，然后通过转巯基化反应将泛素转移至E2缀合酶（4-7）。带电荷的E2 s与E3 s一起发挥泛素化底物的功能（1）。目前认为，Ube 1/Uba 1是动物和真菌中唯一的E1，用于向E2装载泛素（1，8）。在这里，我们确定了不同的E1在脊椎动物和海胆，Uba 6，它特异性激活泛素，但不是其他UBL在体外和体内。人Uba 6和Ube 1在体外对E2充电有不同的偏好，它们的特异性部分取决于它们的C-末端泛素折叠结构域，该结构域招募E2。在组织培养细胞中，Uba 6需要充电一个先前未表征的Uba 6特异性E2（E2），而Ube 1需要充电的细胞周期E2 Cdc 34 A和Cdc 34 B。我们的数据揭示了控制泛素结合的途径中意想不到的复杂性，其中双E1协调不同E2队列的充电。
Modification of proteins with ubiquitin or ubiquitin-like proteins (UBLs) by means of an E1-E2-E3 cascade controls many signalling networks(1-3). Ubiquitin conjugation involves adenylation and thioesterification of the carboxy-terminal carboxylate of ubiquitin by the E1-activating enzyme Ube1 (Uba1 in yeast), followed by ubiquitin transfer to an E2-conjugating enzyme through a trans-thiolation reaction(4-7). Charged E2s function with E3s to ubiquitinate substrates(1). It is currently thought that Ube1/Uba1 is the sole E1 for charging of E2s with ubiquitin in animals and fungi(1,8). Here we identify a divergent E1 in vertebrates and sea urchin, Uba6, which specifically activates ubiquitin but not other UBLs in vitro and in vivo. Human Uba6 and Ube1 have distinct preferences for E2 charging in vitro, and their specificity depends in part on their C-terminal ubiquitin-fold domains, which recruit E2s. In tissue culture cells, Uba6 is required for charging a previously uncharacterized Uba6-specific E2 (Use1), whereas Ube1 is required for charging the cell-cycle E2s Cdc34A and Cdc34B. Our data reveal unexpected complexity in the pathways that control the conjugation of ubiquitin, in which dual E1s orchestrate the charging of distinct cohorts of E2s.