Structural and functional analysis of Hikeshi, a new nuclear transport receptor of Hsp70s.
Structural and functional analysis of Hikeshi, a new nuclear transport receptor of Hsp70s.
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Hsp70 的新型核转运受体 Hikeshi 的结构和功能分析。
DOI：
10.1107/s1399004714026881
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Lee SJ.
中科院分区：
文献类型：
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作者：
Song J;Kose S;Watanabe A;Son SY;Choi S;Hong H;Yamashita E;Park IY;Imamoto N;Lee SJ.
Hikeshi是细胞在应激后存活所需的核转运受体。它通过与核孔复合物（NPC）中的蛋白质FG-核孔蛋白（FG-Nups）相互作用介导热休克诱导的70 kDa热休克蛋白（Hsp 70）的核输入。 在这里，人类Hikeshi的晶体结构以1.8 μ m的分辨率呈现。 Hikeshi形成负责与Hsp 70相互作用的不对称同源二聚体。Hikeshi的不对称性源于C-末端结构域（CTD）的不同构象和每个单体的接头区域的柔性。结构引导的突变分析表明，柔性接头区和CTD是重要的核输入热休克蛋白70。Pull-down分析表明，只有全长Hsp 70可以与Hikeshi相互作用。N-末端结构域（NTD）由包含参与FG-Nup识别的疏水口袋的卷曲/β-夹心折叠结构组成。NTD中一个独特的延伸环（E-loop）可能调节Hikeshi与FG-Nups的相互作用。Hikeshi的晶体结构解释了Hikeshi如何通过识别FG-Nups参与核输入的调节，以及Hikeshi的哪个部分影响其与Hsp 70的结合。这项研究是第一个对这种高度独特的进口受体产生结构洞察力的研究。
Hikeshi is a nuclear transport receptor required for cell survival after stress. It mediates heat-shock-induced nuclear import of 70 kDa heat-shock proteins (Hsp70s) through interactions with FG-nucleoporins (FG-Nups), which are proteins in nuclear pore complexes (NPCs). Here, the crystal structure of human Hikeshi is presented at 1.8 Å resolution. Hikeshi forms an asymmetric homodimer that is responsible for the interaction with Hsp70s. The asymmetry of Hikeshi arises from the distinct conformation of the C-terminal domain (CTD) and the flexibility of the linker regions of each monomer. Structure-guided mutational analyses showed that both the flexible linker region and the CTD are important for nuclear import of Hsp70. Pull-down assays revealed that only full-length Hsp70s can interact with Hikeshi. The N-terminal domain (NTD) consists of a jelly-roll/β-sandwich fold structure which contains hydrophobic pockets involved in FG-Nup recognition. A unique extended loop (E-loop) in the NTD is likely to regulate the interactions of Hikeshi with FG-Nups. The crystal structure of Hikeshi explains how Hikeshi participates in the regulation of nuclear import through the recognition of FG-Nups and which part of Hikeshi affects its binding to Hsp70. This study is the first to yield structural insight into this highly unique import receptor.