Dynamic, site-specific interaction of hypoxia-inducible factor-1alpha with the von Hippel-Lindau tumor suppressor protein.
Hypoxia-inducible factor (HIF)-1alpha is a transcription factor that plays a critical role in regulating genes involved in erythropoiesis and angiogenesis. Recent evidence indicates that the von Hippel-Lindau tumor suppressor protein (VHL) is part of a ubiquitin ligase complex that promotes the degradation of HIF-1alpha under normoxic conditions. Under hypoxic conditions, HIF-1alpha is markedly stabilized. A critical issue in understanding the hypoxic response is the identification of hypoxia-regulated steps. We show here that hypoxia and cobalt treatment modulate the capacity of a HIF-1alpha fragment comprising residues 531-652 to coimmunoprecipitate with VHL. Hypoxia and cobalt both significantly diminish the interaction, and furthermore, normoxia treatment after hypoxia rapidly normalizes it. This HIF-1alpha fragment confers hypoxia and cobalt inducibility on a heterologous protein. Significantly, contained within this fragment is a short 27-residue sequence that behaves identically in all respects noted above. Finally, evidence is provided to show that cobalt and hypoxia both induce a posttranslational modification (or loss of one) in HIF-1alpha that affects its binding to VHL. We propose that dynamic, site-specific interaction of HIF-1alpha with VHL provides one mechanism by which HIF-1alpha can be regulated.
Yu
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Department of Pathology, University of Pennsylvania School of Medicine, 605 Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
White
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Zhao
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Lee
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D015687:Cell Hypoxia / Q000502:physiology; D003035:Cobalt / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015151:Immunoblotting; D008025:Ligases; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014157:Transcription Factors / Q000235:genetics; D014162:Transfection; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D003035:Cobalt; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D008025:Ligases; C497446:VHL protein, human