Xkid is degraded in a D-box, KEN-box, and A-box-independent pathway
Xkid is degraded in a D-box, KEN-box, and A-box-independent pathway
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DOI：
10.1128/mcb.23.12.4126-4138.2003
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发表时间：
2003-06-01
影响因子：
5.3
通讯作者：
Lorca, T
中科院分区：
文献类型：
--
作者：
Castro, A;Vigneron, S;Lorca, T
在有丝分裂过程中，Xenopus chromokinesin Kid （Xkid）提供了中期染色体聚集所需的极性抛射力，并在后期需要其降解以诱导染色体分离。尽管事实上Xkid在后期的降解似乎是诱导染色体向两极移动的关键调节因子，但对控制这种蛋白质水解的机制知之甚少。我们研究了Xkid的降解途径。我们证明Xkid在体内和体外都能被AFC/Cdc20和APC/Cdh1降解。我们表明，尽管在其序列中存在五个假定的D-box基序，但Xkid以D-box独立的方式进行蛋白水解。我们在该染色体激酶的C端发现了一个结构域，序列为GxEN，其突变通过APC/Cdc20和APC/Cdh1使该蛋白完全稳定。此外，我们发现该降解序列作为转座基序并诱导GST-GXEN融合蛋白的蛋白水解。最后，我们证明了含有D-box和GXEN的肽完全阻断APC依赖性cyclin B和Xkid的降解，这表明GXEN结构域可能介导Xkid与APC的识别和关联。
During mitosis, the Xenopus chromokinesin Kid (Xkid) provides the polar ejection forces needed at metaphase for chromosome congression, and its degradation is required at anaphase to induce chromosome segregation. Despite the fact that the degradation of Xkid at anaphase seems to be a key regulatory factor to induce chromosome movement to the poles, little is known about the mechanisms controlling this proteolysis. We investigated here the degradation pathway of Xkid. We demonstrate that Xkid is degraded both in vitro and in vivo by AFC/Cdc20 and APC/Cdh1. We show that, despite the presence of five putative D-box motifs in its sequence, Xkid is proteolyzed in a D-box-independent manner. We identify a domain within the C terminus of this chromokinesin, with sequence GxEN, whose mutation completely stabilizes this protein by both APC/Cdc20 and APC/Cdh1. Moreover, we show that this degradation sequence acts as a transposable motif and induces the proteolysis of a GST-GXEN fusion protein. Finally, we demonstrate that both a D-box and a GXEN-containing peptides completely block APC-dependent degradation of cyclin B and Xkid, indicating that the GXEN domain might mediate the recognition and association of Xkid with the APC.