APC/CCdc20 controls the ubiquitin-mediated degradation of p21 in prometaphase
APC/CCdc20 controls the ubiquitin-mediated degradation of p21 in prometaphase
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DOI：
10.1016/j.molcel.2007.06.013
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发表时间：
2007-08-03
期刊：
影响因子：
16
通讯作者：
Pagano, Michele
中科院分区：
文献类型：
--
作者：
Amador, Virginia;Ge, Sheng;Pagano, Michele
在G1/S转换期间，p2 l蛋白水解由Skp 2介导;然而，p2 l在G2中重新积累并在前中期再次降解。在有丝分裂中如何控制p2 l降解仍然未被探索。我们发现Cdc 20（泛素连接酶APC/C的激活剂）在培养的细胞中结合p2 l，并且鉴定了APC/C-cdc 20介导的p2 l泛素化所必需的p2 l中的D盒基序。Cdc 20或Skp 2的过表达使野生型p2 l不稳定;然而，只有Skp 2而不是Cdc 20能够使p2 l（D盒）突变体不稳定。Cdc 20基因沉默可诱导p21（+/+）前中期细胞中p2 l的积累，增加p2 l与Cdkl结合的比例，并抑制Cdkl活性，但在p21（-/-）细胞中不存在。因此，在前中期，Cdc 20通过介导p2 l的降解来正向调节Cdkl。我们认为ApC/C-cdc 20介导的p2 l降解有助于有丝分裂事件所必需的Cdk 1的完全激活，并防止纺锤体检查点激活过程中的有丝分裂滑移。
During the G1/S transition, p2l proteolysis is mediated by Skp2; however, p2l reaccumulates in G2 and is degraded again in prometaphase. How p2l degradation is controlled in mitosis remains unexplored. We found that Cdc20 (an activator of the ubiquitin ligase APC/C) binds p2l in cultured cells and identified a D box motif in p2l necessary for APC/ C-cdc20- mediated ubiquitylation of p2l. Overexpression of Cdc20 or Skp2 destabilized wildtype p2l; however, only Skp2, but not Cdc20, was able to destabilize a p2l(D box) mutant. Silencing of Cdc20 induced an accumulation of p2l, increased the fraction of p2l bound to Cdkl, and inhibited Cdkl activity in p21(+/+) prometaphase cells, but not in p21(-/-) cells. Thus, in prometaphase Cdc20 positively regulates Cdkl by mediating the degradation of p2l. We propose that the ApC/C-cdc20- mediated degradation of p2l contributes to the full activation of Cdk1 necessary for mitotic events and prevents mitotic slippage during spindle checkpoint activation.