Structural basis for the interaction between FxFG nucleoporin repeats and importin-β in nuclear trafficking
Structural basis for the interaction between FxFG nucleoporin repeats and importin-β in nuclear trafficking
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DOI：
10.1016/s0092-8674(00)00014-3
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发表时间：
2000-07-07
期刊：
影响因子：
64.5
通讯作者：
Stewart, M
中科院分区：
文献类型：
--
作者：
Bayliss, R;Littlewood, T;Stewart, M
我们描述了Importin-beta残基1-442(Ib442)与来自Nsp1p的5个FxFG核孔蛋白重复序列之间的配合物的晶体结构。核孔蛋白FxFG核心结合在Ib442的凸面上，结合到热重复序列5和6的A螺旋之间的初级位点，以及热重复6和7之间的次级位点。初级FxFG结合位点上的Importin-beta IIe178突变减少了结合和核蛋白输入，为Importin-beta-FxFG相互作用的功能意义提供了直接证据。Importin-beta上的FxFG结合位点与RanGTP结合位点不重叠。取而代之的是，RanGTP可能通过产生改变FxFG结合位点结构的构象变化来从FxFG核孔蛋白释放Importin-β。
We describe the crystal structure of a complex between importin-beta residues 1-442 (Ib442) and five FxFG nucleoporin repeats from Nsp1p. Nucleoporin FxFG cores bind on the convex face of Ib442 to a primary site between the A helices of HEAT repeats 5 and 6, and to a secondary site between HEAT repeats 6 and 7. Mutations at importin-beta IIe178 in the primary FxFG binding site reduce both binding and nuclear protein import, providing direct evidence for the functional significance of the importin-beta-FxFG interaction. The FxFG binding sites on importin-beta do not overlap with the RanGTP binding site. Instead, RanGTP may release importin-beta from FxFG nucleoporins by generating a conformational change that alters the structure of the FxFG binding site.