Recruitment of Uev1B to Hrs-containing endosomes and its effect on endosomal trafficking
Recruitment of Uev1B to Hrs-containing endosomes and its effect on endosomal trafficking
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DOI：
10.1016/j.yexcr.2010.04.017
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发表时间：
2010-08-01
影响因子：
3.7
通讯作者：
Sorkin, Alexander
中科院分区：
文献类型：
--
作者：
Duex, Jason E.;Mullins, Michael R.;Sorkin, Alexander
信号受体（例如表皮生长因子受体（EGFR））的内吞作用严格控制由这些受体的配体激活触发的信号转导过程。为了鉴定 EGFR 内吞运输的新调节因子，对参与泛素缀合和 EGFR 下调的基因进行了 RNA 干扰筛选。筛选显示，针对保守泛素结合域 Uev1 的小干扰 RNA (siRNA) 增加了 EGFR 的下调。由于这些 siRNA 同时靶向包含 Uev1 结构域的多个基因，因此我们通过过表达单个 Uev1 相关蛋白来分析这些基因产物的作用。该分析表明，Uev1A (UBE2V1) 的过度表达对 EGFR:EGF 复合物的降解没有影响。相反，Uev1B（TMEM189-UBE2V1亚型2）的过度表达减缓了EGF：受体复合物的降解。发现 Uev1B 蛋白与核内体中的泛素和 Hrs 强烈共定位并关联。此外，Uev1B 的过度表达消除了 Hrs 与 EGFR 共定位的能力。 Uev1B 的 B 结构域（而不是 UEV 结构域）主要负责观察到的表型，表明 B 结构域内存在新的内体靶向序列。总之，数据表明，细胞中 Uev1B 蛋白水平升高，通过与泛素化蛋白和 Hrs 结合，导致内体分选效率降低。由爱思唯尔公司出版
Endocytosis of signaling receptors, such as epidermal growth factor receptor (EGFR), tightly controls the signal transduction process triggered by ligand activation of these receptors. To identify new regulators of the endocytic trafficking of EGFR an RNA interference screen was performed for genes involved in ubiquitin conjugation and down-regulation of EGFR. The screen revealed that small interfering RNAs (siRNAs) that target the conserved ubiquitin-binding domain Uev1 increased down-regulation of EGFR. Since these siRNAs simultaneously targeted multiple genes containing a Uev1 domain, we analyzed the role of these gene products by overexpressing individual Uev1-related proteins. This analysis revealed that overexpression of Uev1A (UBE2V1) has no effect on the degradation of EGFR:EGF complexes. In contrast, overexpression of Uev1B (TMEM189-UBE2V1 isoform 2) slowed the degradation of EGF:receptor complexes. The Uev1B protein was found to strongly colocalize and associate with ubiquitin and Hrs in endosomes. Moreover, overexpression of Uev1B abrogated the ability of Hrs to colocalize with EGFR. The B-domain of Uev1B, and not the UEV-domain, was mainly responsible for the observed phenotypes suggesting the presence of a novel endosomal targeting sequence within the B-domain. Together, the data show that elevated levels of Uev1B protein in cells lead to decreased efficiency of endosomal sorting by associating with ubiquitinated proteins and Hrs. Published by Elsevier Inc.