PROTEIN IMPORT INTO NUCLEI - ASSOCIATION AND DISSOCIATION REACTIONS INVOLVING TRANSPORT SUBSTRATE, TRANSPORT FACTORS, AND NUCLEOPORINS
PROTEIN IMPORT INTO NUCLEI - ASSOCIATION AND DISSOCIATION REACTIONS INVOLVING TRANSPORT SUBSTRATE, TRANSPORT FACTORS, AND NUCLEOPORINS
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DOI：
10.1016/0092-8674(95)90181-7
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发表时间：
1995-12-01
期刊：
影响因子：
64.5
通讯作者：
BLOBEL, G
中科院分区：
文献类型：
--
作者：
REXACH, M;BLOBEL, G
在溶液结合试验中，通过检测含有核定位信号（NLS）的蛋白质、转运因子核转运蛋白α、核转运蛋白β和Ran与核孔蛋白的FXFG或GLGG重复区之间的相互作用，检查核蛋白输入的分子动力学。我们发现，karyopherins α和β合作，结合FXFG，但不GLGG重复区。NLS蛋白与核转运蛋白α的结合被核转运蛋白β增强。发现了两个新的反应。首先，孵育的karyopherin异源二聚体-NLS蛋白复合物与FXFG重复区刺激NLS蛋白从karyopherin异源二聚体的解离。第二，将核转运蛋白异源二聚体与RanGTP（或与不能水解GTP的Ran突变体）孵育导致核转运蛋白α从β中解离，并导致Ran与核转运蛋白β结合; RanGDP没有影响。我们认为NLS蛋白质穿过核孔复合物的运动是一个随机过程，通过重复的结合-解离反应进行。
The molecular dynamics of nuclear protein import were examined in a solution binding assay by testing for interactions between a protein containing a nuclear localization signal (NLS), the transport factors karyopherin alpha, karyopherin beta, and Ran, and FXFG or GLFG repeat regions of nucleoporins. We found that karyopherins alpha and beta cooperate to bind FXFG but not GLFG repeat regions. Binding of the NLS protein to karyopherin alpha was enhanced by karyopherin beta. Two novel reactions were discovered. First, incubation of a karyopherin heterodimer-NLS protein complex with an FXFG repeat region stimulated the dissociation of the NLS protein from the karyopherin heterodimer. Second, incubation of the karyopherin heterodimer with RanGTP (or with a Ran mutant that cannot hydrolyze GTP) led to the dissociation of karyopherin alpha from beta and to an association of Ran with karyopherin beta; RanGDP had no effect. We propose that movement of NLS proteins across the nuclear pore complex is a stochastic process that operates via repeated association-dissociation reactions.