Evidence for the involvement of diacylglycerol kinase in the activation of hypoxia-inducible transcription factor 1 by low oxygen tension.
Hypoxia-inducible factor 1 (HIF-1) induces a gene expression program essential for the cellular adaptation to lowered oxygen environments. The intracellular mechanisms by which hypoxia induces HIF-1 remain poorly understood. Here we show that exposure of various cell types to hypoxia raises the intracellular level of phosphatidic acid primarily through the action of diacylglycerol kinase (DGK). Pharmacological inhibition of DGK activity through use of the specific DGK inhibitors and abrogated specifically HIF-1-dependent transcription analyzed with a HIF-1-responsive reporter plasmid. A more detailed analysis revealed that pharmacological inhibition of DGK activity prevented the hypoxia-dependent accumulation of the HIF-1alpha subunit and the subsequent HIF-1-DNA complex formation as well as hypoxia-induced activity of the HIF-1 transactivation domains localized to amino acids 530-582 and 775-826 of the HIF-1alpha subunit. Our results demonstrate for the first time that accumulation of phosphatidic acid through DGK underlines oxygen sensing and provide evidence for the involvement of this lipid kinase in the intracellular signaling that leads to HIF-1 activation.
Aragonés
J
J
Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Diego de León 62, 28006 Madrid, Spain.
Jones
D R
DR
Martin
S
S
San Juan
M A
MA
Alfranca
A
A
Vidal
F
F
Vara
A
A
Mérida
I
I
Landázuri
M O
MO
D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019852:Diacylglycerol Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004075:Diglycerides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015151:Immunoblotting; D008156:Luciferases / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology; D010957:Plasmids / Q000378:metabolism; D011744:Pyrimidinones / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D052999:Quinazolinones; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D004075:Diglycerides; D004791:Enzyme Inhibitors; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D010712:Phosphatidic Acids; D010743:Phospholipids; D010880:Piperidines; D011744:Pyrimidinones; D011799:Quinazolines; D052999:Quinazolinones; D011994:Recombinant Proteins; D013844:Thiazoles; D014157:Transcription Factors; C058544:R 59949; D004247:DNA; C047505:R 59022; D008156:Luciferases; D019852:Diacylglycerol Kinase; D010100:Oxygen