Steinhoff Amrei, Pientka Friederike Katharina, Möckel Sylvia, Kettelhake Antje, Hartmann Enno, Köhler Matthias, Depping Reinhard
Department of Physiology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Germany.
Biochem Biophys Res Commun. 2009 Oct 2;387(4):705-11. doi: 10.1016/j.bbrc.2009.07.090. Epub 2009 Jul 23.
Hypoxia-inducible factors are crucial in the regulatory process of oxygen homeostasis of vertebrate cells. Inhibition of prolyl hydroxylation of HIF-alpha subunits by prolyl-hydroxylases (PHD1, PHD2 and PHD3) leads to transcription of a greater number of hypoxia responsive genes. We have investigated the subcellular distribution and the molecular mechanisms regulating the intracellular allocation of PHD1 and PHD2. As reported earlier we find PHD1 located exclusively in the nucleus. We demonstrate that nuclear import of PHD1 occurs importin alpha/beta dependently and relies on a nuclear localisation signal (NLS). By contrast PHD2 is cycling between nucleus and cytoplasm, and nuclear import seems to be independent of "classical" importin alpha/beta receptors. Furthermore, we reveal that the exit of PHD2 from the nucleus requires CRM1 and the N-terminal 100 amino acids of the protein. Our findings provide new insights into the mechanisms of the regulation of the oxygen sensor cascade of PHDs in different cellular compartments.
缺氧诱导因子在脊椎动物细胞氧稳态的调节过程中至关重要。脯氨酰羟化酶（PHD1、PHD2和PHD3）对HIF-α亚基脯氨酰羟化的抑制会导致更多缺氧反应基因的转录。我们研究了PHD1和PHD2的亚细胞分布以及调节其细胞内定位的分子机制。如先前报道，我们发现PHD1仅位于细胞核中。我们证明PHD1的核输入依赖于输入蛋白α/β，并且依赖于一个核定位信号（NLS）。相比之下，PHD2在细胞核和细胞质之间循环，并且核输入似乎独立于“经典的”输入蛋白α/β受体。此外，我们发现PHD2从细胞核中输出需要CRM1和该蛋白的N端100个氨基酸。我们的研究结果为不同细胞区室中PHD氧传感器级联反应的调节机制提供了新的见解。
