Transcriptional coregulator SNURF (RNF4) possesses ubiquitin E3 ligase activity
Transcriptional coregulator SNURF (RNF4) possesses ubiquitin E3 ligase activity
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DOI：
10.1016/s0014-5793(04)00070-5
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发表时间：
2004-02-27
期刊：
影响因子：
3.5
通讯作者：
Palvimo, JJ
中科院分区：
文献类型：
--
作者：
Häkli, M;Lorick, KL;Palvimo, JJ
SNURF/RNF4以无名指依赖的方式参与转录调控和生长抑制。在这项工作中，我们证明了SNURF在体外以泛素结合酶(E2)选择性的方式介导其自身的泛素化：SNURF与UbcH5A和B，HHR6B(RAD6B)，E2-25K，MmUbc7和UbcH13作用于E3连接酶，而不与UbcH3，UbcM4，MmUbc6或E2-20K作用。相比之下，特征明确的环E3，AO7只与UbcH5家族的成员一起发挥作用。此外，根据所使用的E2，泛素修饰表现为单泛素化或多泛素化。SNURF环指基序中保守的半胱氨酸残基的突变可以在体外和完整细胞中消除泛素化。小鼠胚胎癌F9细胞蛋白的大小分级表明，大多数内源性SNURF存在于大于或等于500 kDa的耐盐性复合体中，这表明SNURF在多蛋白复合体中起到环状成分的作用。综上所述，SNURF/RNF4具有E3连接酶的功能，这种活性与其转录调控功能密切相关。(C)2004年欧洲生化学会联合会。爱思唯尔出版，版权所有。
SNURF/RNF4 has been implicated in transcriptional regulation and growth inhibition in a RING finger-dependent fashion. In this work, we show that SNURF mediates its own ubiquitination in vitro in a ubiquitin-conjugating enzyme (E2)-selective manner: SNURF acts as an E3 ligase with UbcH5A and B, HHR6B (RAD6B), E2-25K, MmUbc7 and UbcH13, but not with UbcH3, UbcM4, MmUbc6 or E2-20K. In contrast, the well-characterized RING E3, AO7, functions only with members of the UbcH5 family. Furthermore, depending on the E2 used, the ubiquitin modification manifests as mono- or multi-ubiquitination. Mutation of conserved cysteine residues within the RING finger motif of SNURF abolishes the ubiquitination in vitro and in intact cells. Size fractionation of murine embryonal carcinoma F9 cell proteins shows that the majority of endogenous SNURF resides in salt-resistant greater than or equal to500-kDa complexes, suggesting that SNURF functions as a RING component in a multiprotein complex. Taken together, SNURF/RNF4 functions as an E3 ligase and this activity is closely linked to its transcription regulatory functions. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.