E2-C, a cyclin-selective ubiquitin carrier protein required for the destruction of mitotic cyclins
E2-C, a cyclin-selective ubiquitin carrier protein required for the destruction of mitotic cyclins
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DOI：
10.1073/pnas.93.9.4294
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发表时间：
1996-04-30
影响因子：
11.1
通讯作者：
Ruderman, JV
中科院分区：
文献类型：
--
作者：
Aristarkhov, A;Eytan, E;Ruderman, JV
有丝分裂周期蛋白A和B的泛素依赖的蛋白分解是完成有丝分裂和进入下一个细胞周期所必需的。这个过程是由环体催化的，它是一个大约22S的颗粒，含有周期蛋白选择性泛素连接酶活性E3-C，需要周期蛋白选择性泛素载体蛋白(UBC)E2-C。本文报道了从文蛤卵母细胞中纯化和克隆E_2-C的方法。推测的E_2-C氨基酸序列表明它是一个新的UBC家族成员。细菌表达的重组E2-C在体外细胞周期蛋白泛素化实验中具有活性，表现出与天然E2-C相同的底物特异性。这些结果表明，E2-C不是先前认为参与细胞周期蛋白泛素化的UBC4或UBC9的同源蛋白，而是一个具有独特性质的新的UBC家族成员。
Ubiquitin-dependent proteolysis of the mitotic cyclins A and B is required for the completion of mitosis and entry into the next cell cycle. This process is catalyzed by the cyclosome, an approximate to 22S particle that contains a cyclin-selective ubiquitin ligase activity, E3-C, that requires a cyclin-selective ubiquitin carrier protein (UBC) E2-C. Here we report the purification and cloning of E2-C from clam oocytes. The deduced amino acid sequence of E2-C indicates that it is a new UBC family member. Bacterially expressed recombinant E2-C is active in in vitro cyclin ubiquitination assays, where it exhibits the same substrate specificities seen with native E2-C. These results demonstrate that E2-C is not a homolog of UBC4 or UBC9, proteins previously suggested to be involved in cyclin ubiquitination, but is a new UBC family member with unique properties.