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Sci Signal. 2016 May 31;9(430):ra56. doi: 10.1126/scisignal.aaf0583.

Protein kinase A-dependent phosphorylation stimulates the transcriptional activity of hypoxia-inducible factor 1.

Author information

1
Vascular Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
2
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
3
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
4
Vascular Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. gsemenza@jhmi.edu.

Abstract

Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes encoding proteins that enable cells to adapt to reduced O2 availability. Proteins encoded by HIF-1 target genes play a central role in mediating physiological processes that are dysregulated in cancer and heart disease. These diseases are also characterized by increased production of cyclic adenosine monophosphate (cAMP), the allosteric activator of cAMP-dependent protein kinase A (PKA). Using glutathione S-transferase pull-down, coimmunoprecipitation, and mass spectrometry analyses, we demonstrated that PKA interacts with HIF-1α in HeLa cervical carcinoma cells and rat cardiomyocytes. PKA phosphorylated Thr(63) and Ser(692) on HIF-1α in vitro and enhanced HIF transcriptional activity and target gene expression in HeLa cells and rat cardiomyocytes. PKA inhibited the proteasomal degradation of HIF-1α in an O2-independent manner that required the phosphorylation of Thr(63) and Ser(692) and was not affected by prolyl hydroxylation. PKA also stimulated the binding of the coactivator p300 to HIF-1α to enhance its transcriptional activity and counteracted the inhibitory effect of asparaginyl hydroxylation on the association of p300 with HIF-1α. Furthermore, increased cAMP concentrations enhanced the expression of HIF target genes encoding CD39 and CD73, which are enzymes that convert extracellular adenosine 5'-triphosphate to adenosine, a molecule that enhances tumor immunosuppression and reduces heart rate and contractility. These data link stimuli that promote cAMP signaling, HIF-1α-dependent changes in gene expression, and increased adenosine, all of which contribute to the pathophysiology of cancer and heart disease.

PMID:
27245613
PMCID:
PMC5541497
DOI:
10.1126/scisignal.aaf0583
[Indexed for MEDLINE]
Free PMC Article

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