Structures of the Karyopherins Kap121p and Kap60p Bound to the Nuclear Pore-Targeting Domain of the SUMO Protease Ulp1p
Structures of the Karyopherins Kap121p and Kap60p Bound to the Nuclear Pore-Targeting Domain of the SUMO Protease Ulp1p
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DOI：
10.1016/j.jmb.2016.11.029
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发表时间：
2017-01-20
影响因子：
5.6
通讯作者：
Matsuura, Yoshiyuki
中科院分区：
文献类型：
--
作者：
Hirano, Hidemi;Kobayashi, Junya;Matsuura, Yoshiyuki
发芽酵母小泛素样修饰物(SUMO)蛋白酶Ulp1p既催化新合成的SUMO向成熟形式的加工，也催化SUMO与靶蛋白的去结合，从而调控广泛的细胞过程，包括细胞分裂、DNA修复、DNA复制、转录和mRNA质量控制。Ulp1p主要定位于核孔复合体(NPC)，通过核粘蛋白Kap121p和Kap95p-Kap60p异源二聚体与一组核孔相关蛋白的相互作用。Ulp1p在核周的滞留对于适当控制蛋白质的脱氨基化是至关重要的。为了深入了解核粘附素在调节Ulp1p定位中的作用，我们确定了Kap121p和Kap60p与Ulp1p的N末端非催化结构域结合的晶体结构，这是NPC靶向的必要条件和充分条件。与先前的假设相反，Ulp1p通过与核粘附素的非常规相互作用与NPC的运输通道相连，我们的结构揭示了Ulp1p具有典型的核定位信号(NLSS)：(1)与Kap121p的NLS结合的异亮氨酸-赖氨酸-NLS(51-55残基)，以及(2)与Kap60p的主要和次要NLS结合的经典二聚体NLS(154-172残基)。Ulp1p还直接与Kap95p结合，Kap6Op的inportin-beta结合结构域增强了Ulp1p与Kap95p的结合。GTP结合的Gsp1p(酵母RAN同源基因)和Exportin Cse1p合作从核粘附素中释放Ulp1p，这表明Ulp1p稳定地结合到NPC上需要一种不依赖于核粘附素的机制来将Ulp1p锚定在NPC上。(C)2016爱思唯尔有限公司。保留所有权利。
The budding yeast small ubiquitin-like modifier (SUMO) protease Ulp1p catalyzes both the processing of newly synthesized SUMO to its mature form and the deconjugation of SUMO from target proteins, thereby regulating a wide range of cellular processes including cell division, DNA repair, DNA replication, transcription, and mRNA quality control. Ulp1p is localized primarily at the nuclear pore complex (NPC) through interactions involving the karyopherins Kap121p and Kap95p-Kap60p heterodimer and a subset of nuclear pore-associated proteins. The sequestration of Ulp1p at the nuclear periphery is crucial for the proper control of protein desumoylation. To gain insights into the role of the karyopherins in regulating the localization of Ulp1p, we have determined the crystal structures of Kap121p and Kap60p bound to the N-terminal non-catalytic domain of Ulp1p that is necessary and sufficient for NPC targeting. Contrary to a previous proposal that Ulp1p is tethered to the transport channel of the NPC through unconventional interactions with the karyopherins, our structures reveal that Ulp1p has canonical nuclear localization signals (NLSs): (1) an isoleucine-lysine-NLS (residues 51-55) that binds to the NLS-binding site of Kap121p, and (2) a classical bipartite NLS (residues 154-172) that binds to the major and minor NLS-binding sites of Kap6Op. Ulp1p also binds Kap95p directly, and the Ulp1p Kap95p binding is enhanced by the innportin-beta-binding domain of Kap6Op. GTP-bound Gsp1p (the yeast Ran ortholog) and the exportin Cse1p cooperate to release Ulp1p from the karyopherins, indicating that the stable sequestration of Ulp1p to the NPC would require a karyopherin-independent mechanism to anchor Ulp1p at the NPC. (C) 2016 Elsevier Ltd. All rights reserved.