Hong Sunghoi, Lee Soyeon, Cho Ssang-Goo, Kang Seongman
Graduate School of Life Sciences and Biotechnology, Korea University, 1, 5ka, Anam-dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea.
Biochem Biophys Res Commun. 2008 Jun 27;371(2):256-60. doi: 10.1016/j.bbrc.2008.04.066. Epub 2008 Apr 24.
UbcH6 is a member of an evolutionally conserved subfamily of E2 ubiquitin-conjugating enzymes. In this study, we report that UbcH6 interacts with and ubiquitinates ataxin-1, the spinocerebellar ataxia type 1 gene product. UbcH6 was identified as an ataxin-1-interacting protein using a yeast two-hybrid screen. UbcH6 co-immunoprecipitates and co-localizes with the ataxin-1 protein in the nucleus. Our binding assays showed that ataxin-1 interacts with UbcH6 through its AXH domain. Interestingly, UbcH6 could ubiquitinate ataxin-1 in the absence of an E3 ligase. The expression level of UbcH6 regulated the rate of ataxin-1 degradation. This study demonstrates that UbcH6 and ataxin-1 are E2-substrate cognate pairs in the ubiquitin-proteasome system.
UbcH6是E2泛素结合酶进化保守亚家族的成员。在本研究中，我们报告UbcH6与脊髓小脑共济失调1型基因产物ataxin-1相互作用并使其泛素化。通过酵母双杂交筛选，UbcH6被鉴定为与ataxin-1相互作用的蛋白。UbcH6与ataxin-1蛋白在细胞核中共免疫沉淀并共定位。我们的结合试验表明，ataxin-1通过其AXH结构域与UbcH6相互作用。有趣的是，在没有E3连接酶的情况下，UbcH6可以使ataxin-1泛素化。UbcH6的表达水平调节ataxin-1的降解速率。本研究表明，在泛素-蛋白酶体系统中，UbcH6和ataxin-1是E2-底物同源对。
