Abstract
Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric bHLH-PAS protein essential for erythropoietin gene transcription in hypoxic cells. Here we show that both 2-aminopurine and sodium fluoride, inhibitors of serine/threonine kinases and phosphatases, respectively, interfered with the hypoxic induction of HIF-1 DNA-binding activity and expression of HIF-1 alpha and HIF-1 beta(ARNT) subunits. Genistein, an inhibitor of tyrosine kinases, completely blocked the synthesis of both HIF-1 subunits as well as HIF-1 DNA-binding activity. Sodium orthovanadate, an inhibitor of tyrosine phosphatases increased the basal level of HIF-1 proteins and HIF-1 activity. These data suggest that protein phosphorylation events play an important role in the hypoxia signal-transduction pathway that leads to synthesis of HIF-1 alpha and HIF-1 beta proteins and the induction of HIF-1 DNA-binding activity.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
2-Aminopurine / pharmacology*
-
Cell Line
-
Cell Nucleus / drug effects
-
Cell Nucleus / metabolism
-
DNA-Binding Proteins / biosynthesis*
-
DNA-Binding Proteins / isolation & purification
-
Enzyme Inhibitors / pharmacology*
-
Gene Expression / drug effects*
-
Humans
-
Hypoxia-Inducible Factor 1
-
Hypoxia-Inducible Factor 1, alpha Subunit
-
Immunoblotting
-
Nuclear Proteins / biosynthesis*
-
Nuclear Proteins / isolation & purification
-
Protein Kinase Inhibitors*
-
Protein Tyrosine Phosphatases / antagonists & inhibitors*
-
Sodium Fluoride / pharmacology*
-
Transcription Factors / biosynthesis*
-
Transcription, Genetic / drug effects
-
Tumor Cells, Cultured
Substances
-
DNA-Binding Proteins
-
Enzyme Inhibitors
-
HIF1A protein, human
-
Hypoxia-Inducible Factor 1
-
Hypoxia-Inducible Factor 1, alpha Subunit
-
Nuclear Proteins
-
Protein Kinase Inhibitors
-
Transcription Factors
-
2-Aminopurine
-
Sodium Fluoride
-
Protein Tyrosine Phosphatases