Importin-beta and the small guanosine triphosphatase Ran mediate chromosome loading of the human chromokinesin Kid.
Importin-beta and the small guanosine triphosphatase Ran mediate chromosome loading of the human chromokinesin Kid.
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DOI：
10.1083/jcb.200708003
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发表时间：
2008-02-11
期刊：
影响因子：
--
通讯作者：
Imamoto N
中科院分区：
文献类型：
--
作者：
Tahara K;Takagi M;Ohsugi M;Sone T;Nishiumi F;Maeshima K;Horiuchi Y;Tokai-Nishizumi N;Imamoto F;Yamamoto T;Kose S;Imamoto N
核细胞质转运因子介导各种细胞过程，包括核转运、纺锤体组装和核膜/孔形成。在本文中，我们确定了染色因子人驱动蛋白样 DNA 结合蛋白 (hKid) 作为 importin-α/β 运输途径的进口货物，并确定了其核定位信号 (NLS)。在失去功能性 NLS 后，hKid 表现出与活细胞有丝分裂染色体的相互作用减少。在洋地黄皂苷通透的有丝分裂细胞中，hKid 仅与纺锤体结合，而不与染色体本身结合。令人惊讶的是，与 importin-α/β 结合的 hKid 能够有效地靶向有丝分裂染色体。添加二磷酸鸟苷和一种能量，可在有丝分裂染色体上局部产生三磷酸鸟苷 (GTP)，增强了 hKid 的输入蛋白-β 介导的染色体负载。我们的结果表明，输入蛋白-β和-α与hKid的关联触发了hKid对有丝分裂染色体的初始靶向，并且局部Ran-GTP介导的货物释放促进了hKid在染色体上的积累。因此，这项研究证明了一种新的核质转运因子介导的机制，用于将蛋白质靶向有丝分裂染色体。
Nucleocytoplasmic transport factors mediate various cellular processes, including nuclear transport, spindle assembly, and nuclear envelope/pore formation. In this paper, we identify the chromokinesin human kinesin-like DNA binding protein (hKid) as an import cargo of the importin-α/β transport pathway and determine its nuclear localization signals (NLSs). Upon the loss of its functional NLSs, hKid exhibited reduced interactions with the mitotic chromosomes of living cells. In digitonin-permeabilized mitotic cells, hKid was bound only to the spindle and not to the chromosomes themselves. Surprisingly, hKid bound to importin-α/β was efficiently targeted to mitotic chromosomes. The addition of Ran–guanosine diphosphate and an energy source, which generates Ran–guanosine triphosphate (GTP) locally at mitotic chromosomes, enhanced the importin-β–mediated chromosome loading of hKid. Our results indicate that the association of importin-β and -α with hKid triggers the initial targeting of hKid to mitotic chromosomes and that local Ran-GTP–mediated cargo release promotes the accumulation of hKid on chromosomes. Thus, this study demonstrates a novel nucleocytoplasmic transport factor–mediated mechanism for targeting proteins to mitotic chromosomes.
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影响因子：
64.5
作者：
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通讯作者：
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作者：
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核蛋白在透化的哺乳动物细胞中进口需要可溶性细胞质因子。
影响因子：
7.8
作者：
Adam, S A;Marr, R S;Gerace, L
通讯作者：
Gerace, L