Importin α1 (Rch1) mediates nuclear translocation of thioredoxin-binding protein-2/vitamin D3-up-regulated protein 1
Importin α1 (Rch1) mediates nuclear translocation of thioredoxin-binding protein-2/vitamin D3-up-regulated protein 1
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DOI：
10.1074/jbc.m405473200
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发表时间：
2004-09-03
影响因子：
4.8
通讯作者：
Yodoi, J
中科院分区：
文献类型：
--
作者：
Nishinaka, Y;Masutani, H;Yodoi, J
硫氧还蛋白结合蛋白-2（TBP-2）/维生素D-3上调蛋白1是一种与硫氧还蛋白（TRX）相互作用的内源性分子，负性调节TRX功能，并参与抑制肿瘤的发展和转移。我们发现，TBP-2异位表达的乳腺癌细胞系MCF-7主要定位在细胞核表现出生长抑制活性。当细胞用抗癌药物辛二酰苯胺异羟肟酸处理时，也证明了内源性TBP-2蛋白的核积累。为了研究核定位的机制，我们进行了酵母双杂交筛选，并确定了输入素α（1）（Rch 1）作为与TBP-2相互作用的蛋白质。TBP-2和Rch 1之间的物理相互作用，证实了谷胱甘肽S-转移酶下拉测定。TBP-2与其他importin α亚家族（Qip 1和NPI-1）中的Rch 1相互作用是特异性的，并且TBP-2的氨基酸1 - 227足以与Rch 1相互作用和核定位，尽管在该序列中没有典型的核定位信号。Rch 1的短干扰RNA的表达抑制辛二酰苯胺异羟肟酸诱导的TBP-2的核积累。总的来说，我们的研究结果强烈表明，与输入系统的相互作用是必需的TBP-2核转位和生长控制与TRX依赖的氧化还原调节转录因子密切相关。
Thioredoxin-binding protein-2 (TBP-2)/vitamin D-3 upregulated protein 1 is an endogenous molecule interacting with thioredoxin (TRX), negatively regulating TRX function, and being implicated in the suppression of tumor development and metastasis. We found that TBP-2 ectopically expressed in the breast cancer cell line MCF-7 was localized predominantly in the nucleus exhibiting growth suppressive activity. The nuclear accumulation of endogenous TBP-2 protein was also demonstrated when the cells were treated with an anticancer drug, suberoylanilide hydroxamic acid. To investigate the mechanism underlying the nuclear localization, we performed a yeast two-hybrid screening and identified importin alpha(1) (Rch1) as a protein interacting with TBP-2. The physical interaction between TBP-2 and Rch1 was confirmed with a glutathione S-transferase pull-down assay. The interaction of TBP-2 was specific to Rch1 among other importin alpha subfamilies (Qip1 and NPI-1), and amino acids 1 - 227 of TBP-2 were sufficient for both the interaction with Rch1 and the nuclear localization, although there is no typical nuclear localization signal in this sequence. The expression of short interfering RNA of Rch1 suppressed suberoylanilide hydroxamic acid-induced nuclear accumulation of TBP-2. Collectively, our results strongly suggest that an interaction with importin system is required for TBP-2 nuclear translocation and growth control tightly associated with TRX-dependent redox regulation of transcription factors.