The infected cell protein 0 of herpes simplex virus 1 dynamically interacts with proteasomes, binds and activates the cdc34 E2 ubiquitin-conjugating enzyme, and possesses in vitro E3 ubiquitin ligase activity
The infected cell protein 0 of herpes simplex virus 1 dynamically interacts with proteasomes, binds and activates the cdc34 E2 ubiquitin-conjugating enzyme, and possesses in vitro E3 ubiquitin ligase activity
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DOI：
10.1073/pnas.161283098
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发表时间：
2001-07-17
影响因子：
11.1
通讯作者：
Roizman, B
中科院分区：
文献类型：
--
作者：
Van Sant, C;Hagglund, R;Roizman, B
单纯疱疹病毒 1 的感染细胞蛋白 0 (ICP0) 是一种混杂的反式激活蛋白，可增强通过感染或转染引入细胞的基因表达，与多种细胞蛋白相互作用，并与 ND10 的破坏和多种蛋白的降解有关。 ICP0 包含一类 E3 泛素连接酶的环指结构域特征。我们报告说：（i）在受感染的细胞中，ICP0 与蛋白酶体动态相互作用，并在蛋白酶体抑制剂 MG132 存在的情况下与蛋白酶体结合。同样在受感染的细胞中，cdc34（一种多泛素化 E2 泛素结合酶）表现出与蛋白酶体的 ICP0 依赖性动态相互作用增加。 (ii) 在体外不依赖于底物的泛素化系统中，ICP0 的外显子 2 编码的 RING Finger 结构域结合 cdc34，而 ICP0 的羧基末端结构域则作为独立于 RING Finger 结构域的 E3 连接酶发挥作用。结果表明ICP0可以作为单分子E3泛素连接酶，促进泛素-蛋白质连接并结合82 cdc34。它与其他单分子 E3 连接酶的不同之处在于，包含环指的结构域结合 E2，而连接酶活性映射到蛋白质的不同结构域。结果还表明，ICP0 在细胞核和细胞质之间穿梭，是其与蛋白酶体动态相互作用的函数。
The infected cell protein 0 (ICP0) of herpes simplex virus 1, a promiscuous transactivator shown to enhance the expression of genes introduced into cells by infection or transfection, interacts with numerous cellular proteins and has been linked to the disruption of ND10 and degradation of several proteins. ICP0 contains a RING finger domain characteristic of a class of E3 ubiquitin ligases. We report that: (i) in infected cells, ICP0 interacts dynamically with proteasomes and is bound to proteasomes in the presence of the proteasome inhibitor MG132. Also in infected cells, cdc34, a polyubiquitinated E2 ubiquitin-conjugating enzyme, exhibits increased ICP0-dependent dynamic interaction with proteasomes. (ii) In an in vitro substrate-independent ubiquitination system, the RING finger domain encoded by exon 2 of ICP0 binds cdc34, whereas the carboxyl-terminal domain of ICP0 functions as an E3 ligase independent of the RING finger domain. The results indicate that ICP0 can act as a unimolecular E3 ubiquitin ligase and that it promotes ubiquitin-protein ligation and binds the 82 cdc34. It differs from other unimolecular E3 ligases in that the domain containing the RING finger binds E2, whereas the ligase activity maps to a different domain of the protein. The results also suggest that ICP0 shuttles between nucleus and cytoplasm as a function of its dynamic interactions with proteasomes.