Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland.
Nat Commun. 2010 May 4;1:13. doi: 10.1038/ncomms1012.
The ubiquitin-like modifier FAT10 targets proteins for degradation by the proteasome and is activated by the E1 enzyme UBA6. In this study, we identify the UBA6-specific E2 enzyme (USE1) as an interaction partner of FAT10. Activated FAT10 can be transferred from UBA6 onto USE1 in vitro, and endogenous USE1 and FAT10 can be coimmunoprecipitated from intact cells. Small interfering RNA-mediated downregulation of USE1 mRNA resulted in a strong reduction of FAT10 conjugate formation under endogenous conditions, suggesting that USE1 is a major E2 enzyme in the FAT10 conjugation cascade. Interestingly, USE1 is not only the first E2 enzyme but also the first known substrate of FAT10 conjugation, as it was efficiently auto-FAT10ylated in cis but not in trans.
泛素样修饰物 FAT10 可将靶蛋白靶向到蛋白酶体进行降解，并通过 E1 酶 UBA6 激活。在本研究中，我们鉴定出 UBA6 特异性 E2 酶（USE1）是 FAT10 的相互作用伙伴。体外实验中，激活的 FAT10 可从 UBA6 转移到 USE1 上，且内源性 USE1 和 FAT10 可从完整细胞中共同免疫沉淀。小干扰 RNA 介导的 USE1 mRNA 下调会导致内源性条件下 FAT10 缀合物的形成明显减少，这表明 USE1 是 FAT10 缀合级联反应中的主要 E2 酶。有趣的是，USE1 不仅是第一个 E2 酶，也是已知的 FAT10 缀合的第一个底物，因为它在顺式中能有效自动 FAT10 化，但在反式中不能。
