Gersch Malte, Gladkova Christina, Schubert Alexander F, Michel Martin A, Maslen Sarah, Komander David
Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
Nat Struct Mol Biol. 2017 Nov;24(11):920-930. doi: 10.1038/nsmb.3475. Epub 2017 Sep 25.
Damaged mitochondria undergo mitophagy, a specialized form of autophagy that is initiated by the protein kinase PINK1 and the ubiquitin E3 ligase Parkin. Ubiquitin-specific protease USP30 antagonizes Parkin-mediated ubiquitination events on mitochondria and is a key negative regulator of mitophagy. Parkin and USP30 both show a preference for assembly or disassembly, respectively, of Lys6-linked polyubiquitin, a chain type that has not been well studied. Here we report crystal structures of human USP30 bound to monoubiquitin and Lys6-linked diubiquitin, which explain how USP30 achieves Lys6-linkage preference through unique ubiquitin binding interfaces. We assess the interplay between USP30, PINK1 and Parkin and show that distally phosphorylated ubiquitin chains impair USP30 activity. Lys6-linkage-specific affimers identify numerous mitochondrial substrates for this modification, and we show that USP30 regulates Lys6-polyubiquitinated TOM20. Our work provides insights into the architecture, activity and regulation of USP30, which will aid drug design against this and related enzymes.
受损的线粒体经历线粒体自噬，这是一种特殊形式的自噬，由蛋白激酶PINK1和泛素E3连接酶Parkin启动。泛素特异性蛋白酶USP30拮抗Parkin介导的线粒体泛素化事件，是线粒体自噬的关键负调节因子。Parkin和USP30分别对Lys6连接的多聚泛素（一种尚未得到充分研究的链类型）的组装或拆卸表现出偏好。在这里我们报告了与单泛素和Lys6连接的双泛素结合的人USP30的晶体结构，这解释了USP30如何通过独特的泛素结合界面实现对Lys6连接的偏好。我们评估了USP30、PINK1和Parkin之间的相互作用，并表明远端磷酸化的泛素链会损害USP30的活性。Lys6连接特异性的亲和分子识别出许多这种修饰的线粒体底物，并且我们表明USP30调节Lys6多聚泛素化的TOM20。我们的工作为USP30的结构、活性和调节提供了见解，这将有助于针对这种及相关酶的药物设计。
