Van Riper Justin, Martinez-Claros Arleth O, Wang Lie, Schneiderman Hannah E, Maheshwari Sweta, Pillon Monica C
Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA.
Therapeutic Innovation Center (THINC), Baylor College of Medicine, Houston, TX, USA.
Nat Commun. 2025 Jul 1;16(1):5848. doi: 10.1038/s41467-025-61091-8.
The SLFN14 endoribonuclease is a post-transcriptional regulator that targets the ribosome and its associated RNA substrates for codon-bias translational repression. SLFN14 nuclease activity is linked to antiviral defense and platelet function. Despite its prominent role in gene regulation, the molecular signals regulating SLFN14 substrate recognition and catalytic activation remain unclear. SLFN14 dysregulation is linked to human diseases, including ribosomopathies and inherited thrombocytopenia, thus underscoring the importance of establishing the signals coordinating its RNA processing activity. Here, we reconstitute active full-length human SLFN14 and report a high-resolution cryoEM reconstruction of the SLFN14•RNA complex. The structure reveals a medallion-like architecture that shares structural homology with other SLFN family members. We unveil a C-terminal hydrophobic intermolecular interface that stabilizes the SLFN14 homodimer without the need for additional molecular signals. We describe compact sequence-independent RNA binding interfaces and highlight the environment of the SLFN14 disease hotspot at the RNA cleft entrance. We show that the SLFN14 endoribonuclease has broad site-specificity in the absence of modified native tRNA, a characteristic not shared with its SLFN11 family member. Finally, we demonstrate that metal-dependent acceptor stem cleavage requires the SLFN14 E-EhK motif and uncover its unexpected parallel with other virus-activatable nucleases.
SLFN14核糖核酸内切酶是一种转录后调节因子，它靶向核糖体及其相关的RNA底物，以进行密码子偏倚的翻译抑制。SLFN14核酸酶活性与抗病毒防御和血小板功能有关。尽管它在基因调控中起着重要作用，但调节SLFN14底物识别和催化激活的分子信号仍不清楚。SLFN14失调与包括核糖体病和遗传性血小板减少症在内的人类疾病有关，因此强调了建立协调其RNA加工活性的信号的重要性。在这里，我们重组了有活性的全长人SLFN14，并报告了SLFN14•RNA复合物的高分辨率冷冻电镜重建。该结构揭示了一种与其他SLFN家族成员具有结构同源性的奖章状结构。我们揭示了一个C端疏水分子间界面，该界面可稳定SLFN14同型二聚体，而无需额外的分子信号。我们描述了紧凑的、不依赖序列的RNA结合界面，并突出了RNA裂隙入口处SLFN14疾病热点的环境。我们表明，在没有修饰的天然tRNA的情况下，SLFN14核糖核酸内切酶具有广泛的位点特异性，这是其SLFN11家族成员所不具备的特征。最后，我们证明金属依赖性受体茎切割需要SLFN14的E-EhK基序，并揭示了它与其他病毒可激活核酸酶的意外相似之处。
