MPF localization is controlled by nuclear export
MPF localization is controlled by nuclear export
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DOI：
10.1093/emboj/17.14.4127
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发表时间：
1998-07-15
期刊：
影响因子：
11.4
通讯作者：
Pines, J
中科院分区：
文献类型：
--
作者：
Hagting, A;Karlsson, C;Pines, J
在真核生物中，有丝分裂由M期促进因子（MPF）启动，所述M期促进因子（MPF）由B型细胞周期蛋白和它们的伴侣蛋白激酶CDK 1组成。在动物细胞中，MPF在间期位于细胞质中，并且在有丝分裂已经开始后移位到细胞核中，之后其与有丝分裂器结合，直到细胞周期蛋白在后期降解，我们已经使用了人类细胞周期蛋白B1和绿色荧光蛋白（GFP）之间的融合蛋白来研究这种动态行为在真实的时间，在活细胞中。我们发现，当我们注射细胞周期蛋白B1-GFP，或细胞周期蛋白B1-GFP结合CDK 1，细胞周期蛋白B1的核输出被最近鉴定的输出因子输出蛋白1（CRM 1）的抑制剂来普霉素B阻断，MPF的核输出由细胞周期蛋白B1中的核输出序列介导，并且输出缺陷型细胞周期蛋白B1在间期核中积累。因此，在间期MPF不断穿梭于细胞核和细胞质之间，但大部分MPF通过快速核输出保留在细胞质中。我们发现，一个细胞周期蛋白突变体与缺陷的核输出信号不增强过早有丝分裂所造成的干扰与调节磷酸化的CDK 1，但更敏感的抑制Wee 1激酶。
In eukaryotes, mitosis is initiated by M phase promoting factor (MPF), composed of B-type cyclins and their partner protein kinase, CDK1, In animal cells, MPF is cytoplasmic in interphase and is translocated into the nucleus after mitosis has begun, after which it associates with the mitotic apparatus until the cyclins are degraded in anaphase, We have used a fusion protein between human cyclin B1 and green fluorescent protein (GFP) to study this dynamic behaviour in real time, in living cells. We found that when we injected cyclin B1-GFP, or cyclin B1-GFP bound to CDK1 (i.e. MPF), into interphase nuclei it is rapidly exported into the cytoplasm, Cyclin B1 nuclear export is blocked by leptomycin B, an inhibitor of the recently identified export factor, exportin 1 (CRM1), The nuclear export of MPF is mediated by a nuclear export sequence in cyclin B1, and an export-defective cyclin B1 accumulates in interphase nuclei. Therefore, during interphase MPF constantly shuttles between the nucleus and the cytoplasm, but the bulk of MPF is retained in the cytoplasm by rapid nuclear export. We found that a cyclin mutant with a defective nuclear export signal does not enhance the premature mitosis caused by interfering with the regulatory phosphorylation of CDK1, but is more sensitive to inhibition by the Wee1 kinase.