Structural insights into ubiquitin recognition and Ufd1 interaction of Npl4
Structural insights into ubiquitin recognition and Ufd1 interaction of Npl4
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DOI：
10.1038/s41467-019-13697-y
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发表时间：
2019-12-13
影响因子：
16.6
通讯作者：
Fukai, Shuya
中科院分区：
文献类型：
--
作者：
Sato, Yusuke;Tsuchiya, Hikaru;Fukai, Shuya
在酵母蛋白酶体降解途径中，Npl4可能是识别lys48连接的多泛素化底物的最上游因子。与Ufd1一起，Npl4形成一个异源二聚体（UN），并作为Cdc48 atp酶的辅助因子。在这里，我们报道了酵母Npl4与lys48连接的二泛素复合物和与Ufd1的Npl4结合基序的晶体结构。lys48连接的二泛素的远端和近端泛素部分主要分别与Npl4 c端结构域（CTD）的c端螺旋和n端环相互作用。突变分析表明，CTD有助于连锁选择性和泛素链的初始结合。Ufd1占据Npl4的Mpr1/Pad1 n端（MPN）结构域的疏水槽，与JAB1/MPN/Mov34金属酶(JAMM)-家族去泛素化酶的MPN结构域的催化槽相对应。这项研究为Cdc48-UN复合物及其组装对多泛素链的识别提供了重要的结构见解。
Npl4 is likely to be the most upstream factor recognizing Lys48-linked polyubiquitylated substrates in the proteasomal degradation pathway in yeast. Along with Ufd1, Npl4 forms a heterodimer (UN), and functions as a cofactor for the Cdc48 ATPase. Here, we report the crystal structures of yeast Npl4 in complex with Lys48-linked diubiquitin and with the Npl4-binding motif of Ufd1. The distal and proximal ubiquitin moieties of Lys48-linked diubiquitin primarily interact with the C-terminal helix and N-terminal loop of the Npl4 C-terminal domain (CTD), respectively. Mutational analysis suggests that the CTD contributes to linkage selectivity and initial binding of ubiquitin chains. Ufd1 occupies a hydrophobic groove of the Mpr1/Pad1 N-terminal (MPN) domain of Npl4, which corresponds to the catalytic groove of the MPN domain of JAB1/MPN/Mov34 metalloenzyme (JAMM)-family deubiquitylating enzyme. This study provides important structural insights into the polyubiquitin chain recognition by the Cdc48-UN complex and its assembly.