Nek9, a novel FACT-associated protein, modulates interphase progression
Nek9, a novel FACT-associated protein, modulates interphase progression
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DOI：
10.1074/jbc.m311477200
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发表时间：
2004-03-05
影响因子：
4.8
通讯作者：
Lee, SC
中科院分区：
文献类型：
--
作者：
Tan, BCM;Lee, SC
异二聚体 Spt16-Pob3/DUF/FACT 复合物是一类染色质结构调节剂，在复制和转录中发挥重要作用。尽管被视为染色质模板的转录延伸子，但人们对哺乳动物 FACT 的作用方式和参与其他分子过程知之甚少。在这里，我们报告了 FACT 的一个新的相互作用和功能伙伴的鉴定，Nek9。 Nek9 与间期核中的 FACT 形成稳定的、类似于 600 kDa 的复合物。其活性形式的特点是磷酸化依赖性电泳迁移率变化以及激活环内保守残基 (Thr(210)) 的磷酸化。当与 FACT 复合时，Nek9 在 Thr(210) 上的磷酸化显着升高。对 Nek9(dsRNAi) 细胞的细胞周期分析直接表明 Nek9 维持正确的 G(1) 和 S 进程，这一作用与磷酸化 Nek9-FACT 复合物的形成在时间上相关。总的来说，这些观察结果证明 Nek9 可能作为 FACT 的活性酶伙伴，介导某些与 FACT 相关的细胞过程，这些过程对于间期进展至关重要。
The heterodimeric Spt16-Pob3/DUF/FACT complex is a class of chromatin structure modulators with important roles in replication and transcription. Although regarded as a transcription elongator for chromatin template, little is known about the mode of action and involvement in other molecular processes of the mammalian FACT. Here we report the identification of a novel interacting and functional partner of FACT, Nek9. Nek9 forms a stable, similar to600-kDa complex with FACT in the interphase nuclei. Its active form is characterized by phosphorylation-dependent electrophoretic mobility shift and phosphorylation at a conserved residue within the activation loop (Thr(210)). When complexed with FACT, Nek9 exhibits markedly elevated phosphorylation on Thr(210). Cell cycle analysis on the Nek9(dsRNAi) cells directly implicated Nek9 in maintaining proper G(1) and S progression, a role temporally correlated to the formation of a phospho-Nek9-FACT complex. Collectively, these observations provide evidence that Nek9, potentially as an active enzymatic partner of FACT, mediates certain FACT-associated cellular processes, which are ultimately essential for interphase progression.