MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK.
Cell and Developmental Biology, Center of Genomic Regulation (CRG), Barcelona, Spain.
Sci Rep. 2018 Sep 26;8(1):14375. doi: 10.1038/s41598-018-32685-8.
Ubiquitylation is a protein modification implicated in several cellular processes. This process is reversible by the action of deubiquinating enzymes (DUBs). USP45 is a ubiquitin specific protease about which little is known, aside from roles in DNA damage repair and differentiation of the vertebrate retina. Here, by using mass spectrometry we have identified Spindly as a new target of USP45. Our data show that Spindly and USP45 are part of the same complex and that their interaction specifically depends on the catalytic activity of USP45. In addition, we describe the type of ubiquitin chains associated with the complex that can be cleaved by USP45, with a preferential activity on K48 ubiquitin chain type and potentially K6. Here, we also show that Spindly is mono-ubiquitylated and this can be specifically removed by USP45 in its active form but not by the catalytic inactive form. Lastly, we identified a new role for USP45 in cell migration, similar to that which was recently described for Spindly.
泛素化是一种涉及多种细胞过程的蛋白质修饰。这一过程可以通过去泛素化酶（DUBs）的作用逆转。USP45 是一种泛素特异性蛋白酶，除了在 DNA 损伤修复和脊椎动物视网膜分化中的作用外，人们对其知之甚少。在这里，我们通过使用质谱法鉴定出 Spindly 是 USP45 的一个新靶标。我们的数据表明，Spindly 和 USP45 是同一复合物的一部分，它们的相互作用特异性依赖于 USP45 的催化活性。此外，我们还描述了与复合物相关的泛素链的类型，这些泛素链可以被 USP45 切割，对 K48 泛素链类型和潜在的 K6 具有优先活性。在这里，我们还表明 Spindly 是单泛素化的，这可以被 USP45 的活性形式特异性去除，但不能被催化失活形式去除。最后，我们发现 USP45 在细胞迁移中具有新的作用，这与最近描述的 Spindly 的作用相似。
