Heh2/Man1 may be an evolutionarily conserved sensor of NPC assembly state.
Heh2/Man1 may be an evolutionarily conserved sensor of NPC assembly state.
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DOI：
10.1091/mbc.e20-09-0584
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发表时间：
2021-07-15
影响因子：
3.3
通讯作者：
Lusk CP
中科院分区：
文献类型：
--
作者：
Borah S;Thaller DJ;Hakhverdyan Z;Rodriguez EC;Isenhour AW;Rout MP;King MC;Lusk CP
Lap 2-emerin-MAN 1（LEM）家族的整合膜蛋白已成为核膜功能和物理完整性所需的内核膜（INM）的重要组分。然而，像许多INM蛋白一样，对LEM蛋白功能的生化相互作用网络的理解有限。在这里，我们表明，Heh 2/Man 1可以与核孔复合物（NPC），特别是内环复合物（IRC），在进化上遥远的酵母的主要支架组件。尽管Heh 2靶向INM需要N-末端结构域，但我们证明了与NPC的更稳定的相互作用是由C-末端翼螺旋（WH）结构域介导的，从而解耦INM靶向和NPC结合。通过缺失Heh 2 WH结构域抑制Heh 2与NPC的相互作用导致NPC聚类。有趣的是，Heh 2与NPC的结合也可以通过敲除几个外环核孔蛋白来破坏。因此，Heh 2与NPC的相互作用取决于两种主要NPC支架复合物的结构完整性。我们提出了一个模型，其中Heh 2作为NPC组装状态的传感器，这可能是重要的NPC质量控制机制和分离的NPC在细胞分裂。
Integral membrane proteins of the Lap2-emerin-MAN1 (LEM) family have emerged as important components of the inner nuclear membrane (INM) required for the functional and physical integrity of the nuclear envelope. However, like many INM proteins, there is limited understanding of the biochemical interaction networks that enable LEM protein function. Here, we show that Heh2/Man1 can interact with major scaffold components of the nuclear pore complex (NPC), specifically the inner ring complex (IRC), in evolutionarily distant yeasts. Although an N-terminal domain is required for Heh2 targeting to the INM, we demonstrate that more stable interactions with the NPC are mediated by a C-terminal winged helix (WH) domain, thus decoupling INM targeting and NPC binding. Inhibiting Heh2’s interactions with the NPC by deletion of the Heh2 WH domain leads to NPC clustering. Interestingly, Heh2’s association with NPCs can also be disrupted by knocking out several outer ring nucleoporins. Thus, Heh2’s interaction with NPCs depends on the structural integrity of both major NPC scaffold complexes. We propose a model in which Heh2 acts as a sensor of NPC assembly state, which may be important for NPC quality control mechanisms and the segregation of NPCs during cell division.