Cdc20 mediates D-box-dependent degradation of Sp100.
Cdc20 mediates D-box-dependent degradation of Sp100.
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Cdc20 介导 Sp100 的 D-box 依赖性降解。
DOI：
10.1016/j.bbrc.2011.10.146
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发表时间：
2011-12
期刊：
影响因子：
--
通讯作者：
陈金中
中科院分区：
文献类型：
--
作者：
陈金中
Cdc 20是后期促进复合物/细胞周期体（APC/C复合物）的共激活剂，其在细胞周期的特定阶段募集底物并介导其降解。Sp100是PML-NB支架蛋白，其在间期定位于核颗粒并且在有丝分裂期间从核颗粒分散，参与病毒抗性、转录调节和凋亡。然而，其在细胞周期中的代谢尚未得到充分表征。我们发现了一个假定的D盒在Sp100使用真核线性基序（ELM）预测数据库。通过突变分析验证了Sp100的推定D-box。Cdc 20的过表达导致HEK 293细胞中内源性Sp100蛋白和过表达Sp100 mRNA的水平降低。只有过表达的Sp100的D-box缺失突变体在也过表达Cdc 20的HEK 293细胞中积累。Cdc 20特异性siRNA敲低Cdc 20导致细胞中Sp100蛋白水平增加。此外，我们发现Cdc 20介导的Sp100降解被蛋白酶体抑制剂MG 132减弱，这表明泛素化途径参与了这一过程。然而，与其他Cdc 20底物不同，其显示振荡的蛋白质水平，Sp100蛋白质的水平在整个细胞周期中保持恒定。此外，内源性Sp100的过表达和敲低对细胞周期没有影响。我们的研究结果表明，sp100是Cdc 20的一个新的底物，它是通过泛素化途径降解。Sp100的完整D盒对于该过程是必要的。这些发现扩展了我们对Sp100和Cdc 20以及它们在泛素化中的作用的认识。
Cdc20 is a co-activator of the anaphase-promoting complex/cyclosome (APC/C complex), which recruits substrates at particular phases of the cell cycle and mediates their degradation. Sp100 is a PML-NB scaffold protein, which localizes to nuclear particles during interphase and disperses from them during mitosis, participates in viral resistance, transcriptional regulation, and apoptosis. However, its metabolism during the cell cycle has not yet been fully characterized. We found a putative D-box in Sp100 using the Eukaryotic Linear Motif (ELM) predictor database. The putative D-box of Sp100 was verified by mutational analysis. Overexpression of Cdc20 resulted in decreased levels of both endogenous Sp100 protein and overexpressed Sp100 mRNA in HEK 293 cells. Only an overexpressed D-box deletion mutant of Sp100 accumulated in HEK293 cells that also overexpressed Cdc20. Cdc20 knockdown by cdc20 specific siRNA resulted in increased Sp100 protein levels in cells. Furthermore, we discovered that the Cdc20 mediated degradation of Sp100 is diminished by the proteasome inhibitor MG132, which suggests that the ubiquitination pathway is involved in this process. However, unlike the other Cdc20 substrates, which display oscillating protein levels, the level of Sp100 protein remains constant throughout the cell cycle. Additionally, both overexpression and knockdown of endogenous Sp100 had no effect on the cell cycle. Our results suggested that sp100 is a novel substrate of Cdc20 and it is degraded by the ubiquitination pathway. The intact D-box of Sp100 was necessary for this process. These findings expand our knowledge of both Sp100 and Cdc20 as well as their role in ubiquitination.
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影响因子：
21.3
作者：
Izawa D;Pines J
通讯作者：
Pines J
影响因子：
11.4
作者：
Milovic-Holm, Kristijana;Krieghoff, Eva;Hofmann, Thomas G.
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4.4
作者：
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C. Szostecki;H. Guldner;H. Netter;H. Will
影响因子：
5.3
作者：
Wasylyk, C;Schlumberger, SE;Wasylyk, B
通讯作者：
Wasylyk, B
DOI：
10.1073/pnas.95.13.7322
发表时间：
1998-06-23
影响因子：
11.1
作者：
Lehming, N;Le Saux, A;Ptashne, M
通讯作者：
Ptashne, M