Dataset Information

The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor ?.

ABSTRACT: Prolyl hydroxylase domain protein 2 (PHD2) (also known as EGLN1) is a key oxygen sensor in mammals that posttranslationally modifies hypoxia-inducible factor ? (HIF-?) and targets it for degradation. In addition to its catalytic domain, PHD2 contains an evolutionarily conserved zinc finger domain, which we have previously proposed recruits PHD2 to the HSP90 pathway to promote HIF-? hydroxylation. Here, we provide evidence that this recruitment is critical both in vitro and in vivo We show that in vitro, the zinc finger can function as an autonomous recruitment domain to facilitate interaction with HIF-?. In vivo, ablation of zinc finger function by a C36S/C42S Egln1 knock-in mutation results in upregulation of the erythropoietin gene, erythrocytosis, and augmented hypoxic ventilatory response, all hallmarks of Egln1 loss of function and HIF stabilization. Hence, the zinc finger ordinarily performs a critical positive regulatory function. Intriguingly, the function of this zinc finger is impaired in high-altitude-adapted Tibetans, suggesting that their adaptation to high altitude may, in part, be due to a loss-of-function EGLN1 allele. Thus, these findings have important implications for understanding both the molecular mechanism of the hypoxic response and human adaptation to high altitude.

SUBMITTER: Arsenault PR

PROVIDER: S-EPMC5007793 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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Publications

The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor α.

Arsenault Patrick R PR Song Daisheng D Chung Yu Jin YJ Khurana Tejvir S TS Lee Frank S FS

Molecular and cellular biology 20160826 18

Prolyl hydroxylase domain protein 2 (PHD2) (also known as EGLN1) is a key oxygen sensor in mammals that posttranslationally modifies hypoxia-inducible factor α (HIF-α) and targets it for degradation. In addition to its catalytic domain, PHD2 contains an evolutionarily conserved zinc finger domain, which we have previously proposed recruits PHD2 to the HSP90 pathway to promote HIF-α hydroxylation. Here, we provide evidence that this recruitment is critical both in vitro and in vivo We show that i ...[more]

PMID: 27325674

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Project description:BackgroundThe endothelin B receptor (ET(B)R) promotes tumorigenesis and melanoma progression through activation by endothelin (ET)-1, thus representing a promising therapeutic target. The stability of hypoxia-inducible factor (HIF)-1alpha is essential for melanomagenesis and progression, and is controlled by site-specific hydroxylation carried out by HIF-prolyl hydroxylase domain (PHD) and subsequent proteosomal degradation.Principal findingsHere we found that in melanoma cells ET-1, ET-2, and ET-3 through ET(B)R, enhance the expression and activity of HIF-1alpha and HIF-2alpha that in turn regulate the expression of vascular endothelial growth factor (VEGF) in response to ETs or hypoxia. Under normoxic conditions, ET-1 controls HIF-alpha stability by inhibiting its degradation, as determined by impaired degradation of a reporter gene containing the HIF-1alpha oxygen-dependent degradation domain encompassing the PHD-targeted prolines. In particular, ETs through ET(B)R markedly decrease PHD2 mRNA and protein levels and promoter activity. In addition, activation of phosphatidylinositol 3-kinase (PI3K)-dependent integrin linked kinase (ILK)-AKT-mammalian target of rapamycin (mTOR) pathway is required for ET(B)R-mediated PHD2 inhibition, HIF-1alpha, HIF-2alpha, and VEGF expression. At functional level, PHD2 knockdown does not further increase ETs-induced in vitro tube formation of endothelial cells and melanoma cell invasiveness, demonstrating that these processes are regulated in a PHD2-dependent manner. In human primary and metastatic melanoma tissues as well as in cell lines, that express high levels of HIF-1alpha, ET(B)R expression is associated with low PHD2 levels. In melanoma xenografts, ET(B)R blockade by ET(B)R antagonist results in a concomitant reduction of tumor growth, angiogenesis, HIF-1alpha, and HIF-2alpha expression, and an increase in PHD2 levels.ConclusionsIn this study we identified the underlying mechanism by which ET-1, through the regulation of PHD2, controls HIF-1alpha stability and thereby regulates angiogenesis and melanoma cell invasion. These results further indicate that targeting ET(B)R may represent a potential therapeutic treatment of melanoma by impairing HIF-1alpha stability.

Dataset Information

The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor ?.

Publications

The Zinc Finger of Prolyl Hydroxylase Domain Protein 2 Is Essential for Efficient Hydroxylation of Hypoxia-Inducible Factor α.

Similar Datasets

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