Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
Department of Earth Sciences, University of Oxford, Oxford, UK.
J Biol Chem. 2023 Sep;299(9):105156. doi: 10.1016/j.jbc.2023.105156. Epub 2023 Aug 10.
In animals, adaptation to changes in cellular oxygen levels is coordinated largely by 2-oxoglutarate-dependent prolyl-hydroxylase domain (PHD) dioxygenase family members, which regulate the stability of their hypoxia-inducible factor (HIF) substrates to promote expression of genes that adapt cells to hypoxia. Recently, 2-aminoethanethiol dioxygenase (ADO) was identified as a novel O-sensing enzyme in animals. Through N-terminal cysteine dioxygenation and the N-degron pathway, ADO regulates the stability of a set of non-transcription factor substrates; the regulators of G-protein signaling 4, 5. and 16 and interleukin-32. Here, we set out to compare and contrast the in cellulo characteristics of ADO and PHD enzymes in an attempt to better understand their co-evolution in animals. We find that ADO operates to regulate the stability of its substrates rapidly and with similar O-sensitivity to the PHD/HIF pathway. ADO appeared less sensitive to iron chelating agents or transition metal exposure than the PHD enzymes, possibly due to tighter catalytic-site Fe coordination. Unlike the PHD/HIF pathway, the ADO/N-degron pathway was not subject to feedback by hypoxic induction of ADO, and induction of ADO substrates was well sustained in response to prolonged hypoxia. The data also reveal strong interactions between proteolytic regulation of targets by ADO and transcriptional induction of those targets, that shape integrated cellular responses to hypoxia. Collectively, our comparative analysis provides further insight into ADO/N-degron-mediated oxygen sensing and its integration into established mechanisms of oxygen homeostasis.
在动物中，细胞内氧气水平变化的适应主要由依赖 2-氧戊二酸的脯氨酰羟化酶结构域（PHD）双加氧酶家族成员协调，这些成员调节其低氧诱导因子（HIF）底物的稳定性，以促进适应低氧的基因表达。最近，2-氨基乙硫醇双加氧酶（ADO）被鉴定为动物中一种新的 O 感应酶。通过 N 端半胱氨酸双加氧作用和 N 降解途径，ADO 调节一组非转录因子底物的稳定性；G 蛋白信号转导调节剂 4、5 和 16 以及白细胞介素 32。在这里，我们着手比较和对比 ADO 和 PHD 酶在细胞内的特性，试图更好地理解它们在动物中的共同进化。我们发现 ADO 快速调节其底物的稳定性，与 PHD/HIF 途径具有相似的 O 敏感性。ADO 对铁螯合剂或过渡金属暴露的敏感性似乎低于 PHD 酶，这可能是由于其催化位点 Fe 配位更紧密。与 PHD/HIF 途径不同，ADO/N 降解途径不受 ADO 缺氧诱导的反馈调节，并且在长时间缺氧时，ADO 底物的诱导仍能很好地维持。数据还揭示了 ADO 对靶标的蛋白水解调节与对靶标的转录诱导之间的强烈相互作用，这些作用塑造了细胞对缺氧的综合反应。总的来说，我们的比较分析为 ADO/N 降解途径介导的氧感应及其整合到现有的氧稳态机制提供了进一步的见解。
