Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, United States.
Bruker Switzerland AG, Industriestrasse 26, CH-8117 Fällanden, Switzerland.
J Magn Reson. 2020 Jan;310:106646. doi: 10.1016/j.jmr.2019.106646. Epub 2019 Nov 11.
Nucleophosmin (NPM1) is an abundant nucleolar protein that aids in the maturation of pre-ribosomal particles and participates in oncogenic stress responses through its interaction with the Alternative Reading Frame tumor suppressor (p14ARF). NPM1 mediates multiple mechanisms of phase separation which contribute to the liquid-like properties of nucleoli. However, the effects of phase separation on the structure and dynamics of NPM1 are poorly understood. Here we show that NPM1 undergoes phase separation with p14ARF in vitro, forming condensates that immobilize both proteins. We probed the structure and dynamics of NPM1 within the condensed phase using solid-state NMR spectroscopy. Our results demonstrate that within the condensed phase, the NPM1 oligomerization domain forms an immobile scaffold, while the central intrinsically disordered region and the C-terminal nucleic acid binding domain exhibit relative mobility.
核仁磷酸蛋白（Nucleophosmin，NPM1）是一种丰富的核仁蛋白，有助于核糖体前体颗粒的成熟，并通过与Alternative Reading Frame 肿瘤抑制因子（p14ARF）相互作用参与致癌应激反应。NPM1 介导多种相分离机制，这些机制有助于核仁的液态性质。然而，相分离对 NPM1 的结构和动力学的影响还知之甚少。在这里，我们表明 NPM1 与 p14ARF 在体外发生相分离，形成固定这两种蛋白质的凝聚物。我们使用固态 NMR 光谱法探测凝聚相中 NPM1 的结构和动力学。我们的结果表明，在凝聚相中，NPM1 寡聚化结构域形成固定的支架，而中央固有无序区域和 C 末端核酸结合结构域则表现出相对的流动性。
