Oxygen sensing by the prolyl-4-hydroxylase PHD2 within the nuclear compartment and the influence of compartmentalisation on HIF-1 signalling
Oxygen sensing by the prolyl-4-hydroxylase PHD2 within the nuclear compartment and the influence of compartmentalisation on HIF-1 signalling
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DOI：
10.1242/jcs.109041
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发表时间：
2012-11-01
影响因子：
4
通讯作者：
Depping, Reinhard
中科院分区：
文献类型：
--
作者：
Pientka, Friederike Katharina;Hu, Jun;Depping, Reinhard
缺氧诱导因子（HIFs）调节200多个参与细胞适应氧气利用率降低的基因。HIF是由三个HIF-α亚基之一和一个HIF-β亚基组成的异二聚体转录因子。在常氧条件下，HIF-α亚基被脯氨酰-4-羟化酶结构域（PHD）蛋白家族成员PHD 1、PHD 2和PHD 3羟基化，导致被von-Hippel-Lindau蛋白识别、遍在化和蛋白酶体降解。已经表明PHD 2是体内HIF-1 α稳定性的关键调节因子。先前关于PHD 2的细胞内分布的研究提供了PHD 2的主要细胞质定位以及核活性的证据。在这里，我们研究了PHD 2中的功能性核转运信号，并确定了氨基酸196-205在核输入中具有关键作用，而氨基酸6-20对核输出很重要。荧光共振能量转移（FRET）显示，PHD 2和HIF-1 α之间的相互作用发生在细胞核和细胞质区室。然而，仅限于细胞质的PHD 2突变体不与HIF-1 α相互作用，并且与位于细胞核中的野生型PHD 2相比，其对靶HIF-1 α的脯氨酰羟化酶活性较低。在这里，我们提出了一个新的模型，其中PHD 2介导的HIF-1 α的羟基化主要发生在细胞核中，并依赖于非常动态的PHD 2亚细胞运输。
Hypoxia-inducible factors (HIFs) regulate more than 200 genes involved in cellular adaptation to reduced oxygen availability. HIFs are heterodimeric transcription factors that consist of one of three HIF-alpha subunits and a HIF-beta subunit. Under normoxic conditions the HIF-alpha subunit is hydroxylated by members of a family of prolyl-4-hydroxylase domain (PHD) proteins, PHD1, PHD2 and PHD3, resulting in recognition by von-Hippel-Lindau protein, ubiquitylation and proteasomal degradation. It has been suggested that PHD2 is the key regulator of HIF-1 alpha stability in vivo. Previous studies on the intracellular distribution of PHD2 have provided evidence for a predominant cytoplasmic localisation but also nuclear activity of PHD2. Here, we investigated functional nuclear transport signals in PHD2 and identified amino acids 196-205 as having a crucial role in nuclear import, whereas amino acids 6-20 are important for nuclear export. Fluorescence resonance energy transfer (FRET) showed that an interaction between PHD2 and HIF-1 alpha occurs in both the nuclear and cytoplasmic compartments. However, a PHD2 mutant that is restricted to the cytoplasm does not interact with HIF-1 alpha and shows less prolyl hydroxylase activity for its target HIF-1 alpha than wild-type PHD2 located in the nucleus. Here, we present a new model by which PHD2-mediated hydroxylation of HIF-1 alpha predominantly occurs in the cell nucleus and is dependent on very dynamic subcellular trafficking of PHD2.