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

John W. Bullen, Irina Tchernyshyov, Ronald J. Holewinski, Lauren Devine, Fan Wu, Vidya Venkatraman, David A Kass, Robert N Cole, Jennifer Van Eyk, Gregg L Semenza

Research output: Contribution to journalArticle

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 Thr63 and Ser692 on HIF-1aα 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 Thr63 andSer692 andwas not affected by prolyl hydroxylation.PKAalso 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.

Original languageEnglish (US)
Article numberRA56
JournalScience Signaling
Volume9
Issue number430
DOIs
StatePublished - May 31 2016

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

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