Protein kinase A-dependent phosphorylation stimulates the transcriptional activity of hypoxia-inducible factor 1, part 2

ABSTRACT: Hypoxia-inducible factor 1 (HIF-1) activates the transcription of genes encoding proteins that enable cells to adapt to reduced O2 availability. HIF-1 controls physiological processes that are dysregulated in cancer and heart disease, including angiogenesis, energy metabolism, and immunity. These disease processes are also characterized by increased activation of adenosine and β-adrenergic receptors, which triggers the synthesis of cyclic adenosine monophosphate (cAMP), the allosteric regulator of cAMP-dependent protein kinase A (PKA). We performed a proteomic screen in cardiomyocytes and identified PKA as a HIF-1α-interacting protein. PKA interacted with HIF-1α and phosphorylated Thr63 and Ser692 in vitro, coimmunoprecipitated with HIF-1α from cell lysates, and enhanced HIF transcriptional activity and target gene expression in human HeLa cells and rat cardiomyocytes. PKA inhibited the proteasomal degradation of HIF-1α in an O2-independent manner that required phosphorylation of Thr63 and Ser692 and was not affected by mutation of Pro402 and Pro564. PKA also stimulated the binding of the coactivator p300 to HIF- 1α to enhance its transcriptional activity and this effect was lost upon mutation of Asn803. These data establish a potential link between stimuli that increase cAMP concentrations and HIF-1α-dependent changes in gene expression, which contribute to the pathophysiology of cancer and heart disease.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Fetal Cardiomyocyte

DISEASE(S): Hypertrophic Cardiomyopathy

SUBMITTER: Vidya Venkatraman  

LAB HEAD: Gregg L. Semenza

PROVIDER: PXD003795 | Pride | 2016-06-07

REPOSITORIES: Pride