Homodimerization of Nemo-like kinase is essential for activation and nuclear localization.
Homodimerization of Nemo-like kinase is essential for activation and nuclear localization.
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DOI：
10.1091/mbc.e10-07-0605
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发表时间：
2011-01-15
影响因子：
3.3
通讯作者：
Ishitani T
中科院分区：
文献类型：
--
作者：
Ishitani S;Inaba K;Matsumoto K;Ishitani T
NLK是一种进化上保守的蛋白激酶，磷酸化几种转录因子。然而，调节NLK活性的分子机制知之甚少。这项研究表明，NLK的同源二聚化是其激活和核定位所必需的。Nemo-like kinase（NLK）是一种进化上保守的蛋白激酶，其磷酸化几种转录因子。然而，调节NLK活性的分子机制知之甚少。在这里，我们表明，同源二聚化的NLK是必需的，其激活和核定位。生化分析表明，NLK是通过在Thr-286的NLK二聚体的分子间自磷酸化激活的。NLK在Cys-425处的突变（其对应于秀丽隐杆线虫NLK同源物lit-1中的缺陷）阻止NLK二聚化，使得NLK在核定位和激酶活性两者中均存在缺陷。相比之下，外部添加神经生长因子，这已被确定为NLK激活剂，诱导内源性NLK蛋白的二聚化和Thr-286自磷酸化。此外，发现NLK的二聚化和Thr-286磷酸化对于NLK诱导神经突样细胞过程至关重要。目前的研究结果表明，二聚化是NLK功能激活所需的初始关键事件。
NLK is an evolutionarily conserved protein kinase that phosphorylates several transcription factors. However, the molecular mechanisms that regulate NLK activity have been poorly understood. This study shows that homodimerization of NLK is required for its activation and nuclear localization. Nemo-like kinase (NLK) is an evolutionarily conserved protein kinase that phosphorylates several transcription factors. However, the molecular mechanisms that regulate NLK activity have been poorly understood. Here we show that homodimerization of NLK is required for its activation and nuclear localization. Biochemical analysis revealed that NLK is activated through intermolecular autophosphorylation of NLK dimers at Thr-286. Mutation of NLK at Cys-425, which corresponds to the defect in the Caenorhabditis elegans NLK homologue lit-1, prevented NLK dimerization, rendering NLK defective in both nuclear localization and kinase activity. By contrast, the external addition of nerve growth factor, which has been previously identified as an NLK activator, induced dimerization and Thr-286 autophosphorylation of endogenous NLK proteins. In addition, both dimerization and Thr-286 phosphorylation of NLK were found to be essential for induction of neurite-like cellular processes by NLK. The present findings suggest that dimerization is an initial key event required for the functional activation of NLK.