Regulation of cell proliferation by the opioid growth factor receptor is dependent on karyopherin β and Ran for nucleocytoplasmic trafficking
Regulation of cell proliferation by the opioid growth factor receptor is dependent on karyopherin β and Ran for nucleocytoplasmic trafficking
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DOI：
10.1258/ebm.2010.010139
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发表时间：
2010-09-01
影响因子：
3.2
通讯作者：
Zagon, Ian S.
中科院分区：
文献类型：
--
作者：
Cheng, Fan;McLaughlin, Patricia J.;Zagon, Ian S.
阿片类生长因子(OGF；[Met(5)-Enkephalin)和OGF受体(OGFr)形成一个内源性和张力活跃的生长调节系统，通过上调细胞周期蛋白依赖的激酶抑制通路来调节细胞增殖。以往的报道证明，OGF-OGFr轴的核质运输依赖于核定位信号。本研究使用与增强型绿色荧光蛋白(EGFP)融合的全长OGFr探针，以及用小干扰RNA(SiRNA)击倒核粘蛋白α1、α2、α3、α4或α6、核粘蛋白β1或RAN，确定了将OGF-OGFr复合体从细胞质输入到细胞核所需的特定转运因子。人头颈部鳞状细胞癌(鳞状细胞癌-1，SCC-1)核粘附素β1或RAN表达下调，但不能将OGFr-EGFP转运到细胞核中。此外，在SCC-1细胞中，转导核粘蛋白β1或RAN的siRNAs的BrdU标记细胞数比转导干扰siRNA的细胞数多44%。在核粘蛋白α1、α2、α3、α4或α6的siRNA处理的培养细胞中，OGFr-EGFP或BrdU标记指数的分布没有变化。这些结果表明，OGF-OGFr轴对细胞增殖的调节依赖于核粘蛋白β1的核质转运以及RanGTP/RanGDP跨核膜的梯度，而不依赖于与核粘蛋白α相关的接头分子。因此，OGF-OGFr复合体的通道控制了从细胞质到细胞核的进入，而这种货物及时和忠实地跨核膜转运对细胞增殖至关重要。这些核进口的分级水平为OGF-OGFr的微妙调控提供了多种途径，因为它与细胞增殖事件的控制有关。
The opioid growth factor (OGF; [Met(5)-enkephalin) and the OGF receptor (OGFr) form an endogenous and tonically active growth-regulating system that modulates cell proliferation by upregulating the cyclin-dependent kinase inhibitory pathway. Previous reports have documented that nucleocytoplasmic trafficking of the OGF-OGFr axis is dependent on nuclear localization signals. This study determined the specific transport factors required for the import of the OGF-OGFr complex from the cytoplasm to the nucleus using a probe of full-length OGFr fused to enhanced green fluorescent protein (eGFP) and knockdown of karyopherin alpha 1, alpha 2, alpha 3, alpha 4 or alpha 6, karyopherin beta 1 or Ran with small interfering RNA (siRNA). A human squamous cell carcinoma of the head and neck cell line (squamous cell carcinoma-1, SCC-1) that was downregulated for karyopherin beta 1 or Ran did not have transport of OGFr-eGFP into the nucleus. Moreover, there was an increase of 44% in bromodeoxyuridine (BrdU)-labeled cells in cultures of SCC-1 that were transfected with siRNAs to karyopherin beta 1 or Ran compared with cells transfected with scrambled siRNA. No alteration in distribution of OGFr-eGFP or BrdU labeling indexes was recorded in cultures treated with siRNAs to karyopherin alpha 1, alpha 2, alpha 3, alpha 4 or alpha 6. These results indicate that the regulation of cell proliferation by the OGF-OGFr axis is dependent on nucleocytoplasmic transport by karyopherin beta 1 as well as the gradient of RanGTP/RanGDP across the nuclear envelope, but is not reliant on adaptor molecules related to karyopherin alpha. Thus, the passage of the OGF-OGFr complex has controlled entry from the cytoplasm to the nucleus, and the timely and faithful translocation of this cargo across the nuclear envelope is critical to cell proliferation. These hierarchical levels of nuclear import provide multiple pathways for the subtle regulation of OGF-OGFr as it relates to the control of cell proliferative events.