The University of Texas at Dallas, Department of Biological Sciences, Richardson, TX, USA.
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
Nat Commun. 2021 Nov 23;12(1):6789. doi: 10.1038/s41467-021-27160-4.
Processing bodies (p-bodies) are a prototypical phase-separated RNA-containing granule. Their abundance is highly dynamic and has been linked to translation. Yet, the molecular mechanisms responsible for coordinate control of the two processes are unclear. Here, we uncover key roles for eEF2 kinase (eEF2K) in the control of ribosome availability and p-body abundance. eEF2K acts on a sole known substrate, eEF2, to inhibit translation. We find that the eEF2K agonist nelfinavir abolishes p-bodies in sensory neurons and impairs translation. To probe the latter, we used cryo-electron microscopy. Nelfinavir stabilizes vacant 80S ribosomes. They contain SERBP1 in place of mRNA and eEF2 in the acceptor site. Phosphorylated eEF2 associates with inactive ribosomes that resist splitting in vitro. Collectively, the data suggest that eEF2K defines a population of inactive ribosomes resistant to recycling and protected from degradation. Thus, eEF2K activity is central to both p-body abundance and ribosome availability in sensory neurons.
处理体（p-bodies）是一种典型的相分离 RNA 包含的颗粒。它们的丰度具有高度动态性，并与翻译有关。然而，负责协调控制这两个过程的分子机制尚不清楚。在这里，我们揭示了真核延伸因子 2 激酶（eEF2K）在控制核糖体可用性和 p 体丰度方面的关键作用。eEF2K 作用于一个已知的底物，eEF2，来抑制翻译。我们发现 eEF2K 激动剂奈非那韦可在感觉神经元中消除 p 体并损害翻译。为了探测后者，我们使用了 cryo-electron microscopy。奈非那韦稳定了空位的 80S 核糖体。它们在接受部位含有 SERBP1 而不是 mRNA 和 eEF2。磷酸化的 eEF2 与不活跃的核糖体结合，这些核糖体在体外不易分裂。总的来说，这些数据表明 eEF2K 定义了一个不活跃的核糖体群体，它们对再循环有抵抗力，并受到保护免受降解。因此，eEF2K 的活性是感觉神经元中 p 体丰度和核糖体可用性的核心。
