Stockum Anna, Snijders Ambrosius P, Maertens Goedele N
Imperial College London, Department of Medicine, Division of Infectious Diseases, Norfolk Place, London, United Kingdom.
Francis Crick Institute, The Crick Mass Spectrometry Science Technology Platform, 1 Midland Road, London, United Kingdom.
PLoS One. 2018 Jan 2;13(1):e0190513. doi: 10.1371/journal.pone.0190513. eCollection 2018.
Correct segregation of the mitotic chromosomes into daughter cells is a highly regulated process critical to safeguard genome stability. During M phase the spindle assembly checkpoint (SAC) ensures that all kinetochores are correctly attached before its inactivation allows progression into anaphase. Upon SAC inactivation, the anaphase promoting complex/cyclosome (APC/C) E3 ligase ubiquitinates and targets cyclin B and securin for proteasomal degradation. Here, we describe the identification of Ribonucleic Acid Export protein 1 (RAE1), a protein previously shown to be involved in SAC regulation and bipolar spindle formation, as a novel substrate of the deubiquitinating enzyme (DUB) Ubiquitin Specific Protease 11 (USP11). Lentiviral knock-down of USP11 or RAE1 in U2OS cells drastically reduces cell proliferation and increases multipolar spindle formation. We show that USP11 is associated with the mitotic spindle, does not regulate SAC inactivation, but controls ubiquitination of RAE1 at the mitotic spindle, hereby functionally modulating its interaction with Nuclear Mitotic Apparatus protein (NuMA).
有丝分裂染色体正确分离到子细胞中是一个受到高度调控的过程，对维护基因组稳定性至关重要。在M期，纺锤体组装检查点（SAC）确保所有动粒在其失活允许进入后期之前正确附着。SAC失活后，后期促进复合物/细胞周期体（APC/C）E3连接酶将细胞周期蛋白B和分离酶泛素化并靶向蛋白酶体降解。在此，我们描述了核糖核酸输出蛋白1（RAE1）的鉴定，该蛋白先前已被证明参与SAC调控和双极纺锤体形成，是去泛素化酶（DUB）泛素特异性蛋白酶11（USP11）的一种新底物。在U2OS细胞中通过慢病毒敲低USP11或RAE1会显著降低细胞增殖并增加多极纺锤体形成。我们表明USP11与有丝分裂纺锤体相关，不调节SAC失活，但控制有丝分裂纺锤体处RAE1的泛素化，从而在功能上调节其与核有丝分裂装置蛋白（NuMA）的相互作用。
