小柯机器人

德国美茵茨大学Edward A. Lemke等研究人员合作实现原位可视化无序的核运输机器。2023年4月26日，国际知名学术期刊《自然》在线发表了这一成果。

研究人员表示，约120 MDa的哺乳动物核孔复合体（NPC）充当了细胞核和细胞膜之间运输的守门员。NPC的中央通道由数百个称为FG-核蛋白（FG-NUP）的内在无序蛋白质（IDP）填充。虽然NPC支架的结构已被解决得非常详细，但由FG-NUP建立的实际运输机器（约50 MDa）在即使是高分辨断层图和/或用人工智能计算的结构中仍被描述为一个约60纳米的孔。

通过使用合成生物学的位点特异性小分子标记方法和高度时间分辨的荧光显微镜，研究人员在活细胞和具有完整运输机制的透化细胞中直接探测了NPC内重要的FG-NUP98的构象。对FG-NUP98段距离分布的单透化细胞测量与NPC的粗粒度分子模拟相结合，使研究人员能够绘制纳米化运输通道内的未知分子环境。用Flory聚合物理论的术语来说，研究人员确定该通道提供了一个 “良好的溶剂 ”环境。这使FG结构域能够采取扩展的构象，从而控制细胞核和细胞质之间的运输。由于30%以上的蛋白质组是由IDP形成的，这项研究为解决IDP在原位的无序-功能关系打开了一扇窗，这在各种过程中都很重要，如细胞信号、相分离、衰老和病毒进入。

附：英文原文

Title: Visualizing the disordered nuclear transport machinery in situ

Author: Yu, Miao, Heidari, Maziar, Mikhaleva, Sofya, Tan, Piau Siong, Mingu, Sara, Ruan, Hao, Reinkemeier, Christopher D., Obarska-Kosinska, Agnieszka, Siggel, Marc, Beck, Martin, Hummer, Gerhard, Lemke, Edward A.

Issue&Volume: 2023-04-26

Abstract: The approximately 120MDa mammalian nuclear pore complex (NPC) acts as a gatekeeper for the transport between the nucleus and cytosol1. The central channel of the NPC is filled with hundreds of intrinsically disordered proteins (IDPs) called FG-nucleoporins (FG-NUPs)2,3. Although the structure of the NPC scaffold has been resolved in remarkable detail, the actual transport machinery built up by FG-NUPs—about 50MDa—is depicted as an approximately 60-nm hole in even highly resolved tomograms and/or structures computed with artificial intelligence4,5,6,7,8,9,10,11. Here we directly probed conformations of the vital FG-NUP98 inside NPCs in live cells and in permeabilized cells with an intact transport machinery by using a synthetic biology-enabled site-specific small-molecule labelling approach paired with highly time-resolved fluorescence microscopy. Single permeabilized cell measurements of the distance distribution of FG-NUP98 segments combined with coarse-grained molecular simulations of the NPC allowed us to map the uncharted molecular environment inside the nanosized transport channel. We determined that the channel provides—in the terminology of the Flory polymer theory12—a ‘good solvent’ environment. This enables the FG domain to adopt expanded conformations and thus control transport between the nucleus and cytoplasm. With more than 30% of the proteome being formed from IDPs, our study opens a window into resolving disorder–function relationships of IDPs in situ, which are important in various processes, such as cellular signalling, phase separation, ageing and viral entry.

DOI: 10.1038/s41586-023-05990-0

Source: https://www.nature.com/articles/s41586-023-05990-0

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
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