Function and subcellular location of Ro52β
Function and subcellular location of Ro52β
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DOI：
10.1016/j.bbrc.2005.12.084
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发表时间：
2006-02-17
影响因子：
3.1
通讯作者：
Kamitani, T
中科院分区：
文献类型：
--
作者：
Wada, K;Tanji, K;Kamitani, T
自身抗原Ro52 α最近被鉴定为E3泛素连接酶。它的剪接变体Ro52 β，缺乏亮氨酸拉链，尚未被表征。因此，我们将Ro52 β与Ro52 α进行了对比。我们的生化分析表明，Ro52 a和Ro52 β的功能作为E3泛素连接酶和自我泛素化的合作UbcH5B在体外。此外，Ro52 α和Ro52 β在HEK293 T细胞中与泛素一起过表达时都被泛素化，这表明两者在体内都作为E3连接酶起作用并自我泛素化。然而，细胞学研究表明，Ro52 α主要定位于细胞质杆状结构，而Ro52 β弥散定位于细胞质和细胞核。由于亮氨酸拉链在Ro52 α的同源二聚化和异源二聚化中起作用，所以Ro52 α定位于棒状结构可能需要二聚化。基于这些结果，Ro52 alpha和Ro52 beta似乎在不同的位置泛素化其特定的底物。(c)2005年爱思唯尔公司All rights reserved.
Autoantigen Ro52 alpha was recently identified as an E3 ubiquitin ligase. Its splicing variant Ro52 beta, which lacks a leucine zipper, has not been characterized yet. We therefore characterized Ro52 beta in contrast to Ro52 alpha. Our biochemical assays revealed that both Ro52a and Ro52 beta function as E3 ubiquitin ligases and self-ubiquitinate in cooperation with UbcH5B in vitro. In addition, both Ro52 alpha and Ro52 beta are ubiquitinated when overexpresscd with ubiquitin in HEK293T cells, Suggesting that both function as E3 ligases and self-ubiquitinate in vivo. However, cytological studies revealed that Ro52 alpha mainly localizes to the cytoplasmic rod-like structures, whereas Ro52 beta diffusely localizes to both the cytoplasm and the nucleus. Since the leucine zipper plays a role in the homodimerization and heterodimerization of Ro52 alpha, the dimerization might be required for the localization of Ro52 alpha to the rod-like Structures. On the basis of these results, Ro52 alpha and Ro52 beta appear to ubiquitinate their particular substrates at different locations. (c) 2005 Elsevier Inc. All rights reserved.