Versatile function of the circadian protein CIPC as a regulator of Erk activation.
Versatile function of the circadian protein CIPC as a regulator of Erk activation.
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DOI：
10.1016/j.bbrc.2015.11.117
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发表时间：
2016-01
影响因子：
3.1
通讯作者：
Ryota Matsunaga;Tasuku Nishino;A. Yokoyama;A. Nakashima;U. Kikkawa;H. Konishi
中科院分区：
文献类型：
--
作者：
Ryota Matsunaga;Tasuku Nishino;A. Yokoyama;A. Nakashima;U. Kikkawa;H. Konishi
生物钟相互作用蛋白 Circadian (CIPC) 已被确定为生物钟的另一个负反馈调节器。然而，最近对 CIPC 敲除小鼠的研究表明，CIPC 并不是基本生物钟功能所必需的，这表明 CIPC 还具有其他未知的生物学作用。在本研究中，我们重点研究 CIPC 的细胞周期依赖性核质穿梭功能并鉴定其结合蛋白。 Lys186 和 187 被鉴定为 CIPC 核定位信号 (NLS) 内的必需氨基酸残基。我们鉴定了 CIPC 结合蛋白，例如多功能酶 CAD 蛋白（氨基甲酰磷酸合成酶 2、天冬氨酸转氨甲酰酶和二氢乳清酶），它是嘧啶从头合成的关键酶。与对照细胞相比，过表达野生型 CIPC 的 HEK293 细胞表现出细胞增殖受到抑制和细胞周期延迟。我们还发现 PMA 诱导的 Erk 激活受到野生型 CIPC 表达的抑制。相比之下，CIPC 的 NLS 突变体降低了 CIPC 转位到细胞核的能力，但没有表现出这些生物学效应。由于 CAD 和 Erk 在细胞增殖和细胞周期中具有重要作用，CIPC 可能通过与这些结合蛋白相互作用而充当细胞周期调节剂。
The CLOCK-interacting protein, Circadian (CIPC), has been identified as an additional negative-feedback regulator of the circadian clock. However, recent study on CIPC knockout mice has shown that CIPC is not critically required for basic circadian clock function, suggesting other unknown biological roles for CIPC. In this study, we focused on the cell cycle dependent nuclear-cytoplasmic shuttling function of CIPC and on identifying its binding proteins. Lys186 and 187 were identified as the essential amino acid residues within the nuclear localization signal (NLS) of CIPC. We identified CIPC-binding proteins such as the multifunctional enzyme CAD protein (carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, and dihydroorotase), which is a key enzyme for de novo pyrimidine synthesis. Compared to control cells, HEK293 cells overexpressing wild-type CIPC showed suppressed cell proliferation and retardation of cell cycle. We also found that PMA-induced Erk activation was inhibited with expression of wild-type CIPC. In contrast, the NLS mutant of CIPC, which reduced the ability of CIPC to translocate into the nucleus, did not exhibit these biological effects. Since CAD and Erk have significant roles in cell proliferation and cell cycle, CIPC may work as a cell cycle regulator by interacting with these binding proteins.