The Nsp1p carboxy-terminal domain is organized into functionally distinct coiled-coil regions required for assembly of nucleoporin subcomplexes and nucleocytoplasmic transport
The Nsp1p carboxy-terminal domain is organized into functionally distinct coiled-coil regions required for assembly of nucleoporin subcomplexes and nucleocytoplasmic transport
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DOI：
10.1128/mcb.21.23.7944-7955.2001
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发表时间：
2001-12-01
影响因子：
5.3
通讯作者：
Hurt, E
中科院分区：
文献类型：
--
作者：
Bailer, SM;Balduf, C;Hurt, E
核孔蛋白Nsp 1 p在必需的羧基末端结构域中具有四个预测的卷曲螺旋区域（螺旋1至4），其独特之处在于它是两种不同的核孔复合物（NPC）亚复合物Nsp 1 p-Nup 57 p-Nup 49 p-Nic 96 p和Nsp 1 p-Nup 82 p-Nup 159 p的一部分。如体外重构所示，卷曲螺旋区2（残基673至738）足以形成异源三聚体核心复合物，并且可以结合Nup 57 p或Nup 82 p。因此，Nup 82 p与Nsp 1 p螺旋2的相互作用被过量的Nup 57 p竞争。引人注目的是，螺旋3和4突变体仍然组装成核心Nsp 1 p-Nup 57 p-Nup 49 p复合物，但不再与Nic 96 p结合。因此，在nsp 1 coil 3和4突变细胞中，Nsp 1 p-Nup 57 p-Nup 49 p核心复合物从核孔中解离，结果观察到核蛋白输入缺陷。最后，nsp 1-L 640 S温度敏感性突变，其映射在螺旋1中，导致强烈的核mRNA输出缺陷。因此，不同的卷曲螺旋区域内Nsp 1 p-C有不同的功能，这些功能与组装不同的NPC亚复合物，核质运输，并纳入核孔。
Nucleoporin Nsp1p, which has four predicted coiled-coil regions (coils 1 to 4) in the essential carboxyterminal domain, is unique in that it is part of two distinct nuclear pore complex (NPC) subcomplexes, Nsp1p-Nup57p-Nup49p-Nic96p and Nsp1p-Nup82p-Nup159p. As shown by in vitro reconstitution, coiled-coil region 2 (residues 673 to 738) is sufficient to form heterotrimeric core complexes and can bind either Nup57p or Nup82p. Accordingly, interaction of Nup82p with Nsp1p coil 2 is competed by excess Nup57p. Strikingly, coil 3 and 4 mutants are still assembled into the core Nsp1p-Nup57p-Nup49p complex but no longer associate with Nic96p. Consistently, the Nsp1p-Nup57p-Nup49p core complex dissociates from the nuclear pores in nsp1 coil 3 and 4 mutant cells, and as a consequence, defects in nuclear protein import are observed. Finally, the nsp1-L640S temperature-sensitive mutation, which maps in coil 1, leads to a strong nuclear mRNA export defect. Thus, distinct coiled-coil regions within Nsp1p-C have separate functions that are related to the assembly of different NPC subcomplexes, nucleocytoplasmic transport, and incorporation into the nuclear pores.