Calpain-dependent proteolytic cleavage of the p35 cyclin-dependent kinase 5 activator to p25
Calpain-dependent proteolytic cleavage of the p35 cyclin-dependent kinase 5 activator to p25
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DOI：
10.1074/jbc.m907757199
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发表时间：
2000-06-02
影响因子：
4.8
通讯作者：
Hisanaga, S
中科院分区：
文献类型：
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作者：
Kusakawa, G;Saito, T;Hisanaga, S
细胞周期蛋白依赖性激酶5(CDK5)是一种独特的CDK，其活性存在于有丝分裂后神经元中。到目前为止，从哺乳动物脑中纯化的CDK5一直与CDK5的35 kDa主要脑特异性激活物(p35，也称为nck 5a)的截短形式有关，即p25。在这项研究中，我们报道了p35在硝基和体内都可以被calain切割成p25。在大鼠脑提取液中，通过与钙离子孵育，p35被切割成p25。这种裂解被来自calastatin的calain抑制肽抑制，并通过离心法将p35.CDK5从calain中分离出来而被去除。离心后在小球中回收的p35可以被纯化的calain切割成p25。在原代培养的神经细胞中，用钙离子载体和钙离子处理也能诱导p35的裂解，并被Calain抑制剂I抑制。这种裂解使CDK5活性复合体的溶解度从颗粒组分变为可溶组分，但不影响组蛋白H1激酶的活性。在经历细胞死亡的培养神经元中检测到裂解增加，这表明裂解在神经细胞死亡中起作用。
Cyclin-dependent kinase 5 (CDK5) is a unique CDK, the activity of which can be detected in postmitotic neurons. To date, CDK5 purified from mammalian brains has always been associated with a truncated form of the 35-kDa major brain specific activator (p35, also known as nck5a) of CDK5, known as p25. In this study,we report that p35 can be cleaved to p25 both in nitro and in vivo by calpain. In a rat brain extract, p35 was cleaved to p25 by incubation with Ca2+. This cleavage was inhibited by a calpain inhibitor peptide derived from calpastatin and was ablated by separating the p35.CDK5 from calpain by centrifugation. The p35 recovered in the pellet after centrifugation could then be cleaved to p25 by purified calpain. Cleavage of p35 was also induced in primary cultured neurons by treatment with a Ca2+ ionophore and Ca2+ and inhibited by calpain inhibitor I. The cleavage changed the solubility of the CDK5 active complex from the particulate fraction to the soluble fraction but did not affect the histone H1 kinase activity. Increased cleavage was detected in cultured neurons undergoing cell death, suggesting a role of the cleavage in neuronal cell death.