Nuclear localization of hypoxia-inducible factor-2alpha in bovine arterial endothelial cells.
Hypoxia-inducible factor (HIF)-2alpha is a recently identified hypoxia-inducible transcription factor abundantly expressed in vascular endothelial cells. As well as HIF-1alpha, HIF-2alpha forms a heterodimeric complex with the aryl hydrocarbon receptor nuclear translocator and upregulates hypoxia-inducible genes such as vascular endothelial growth factor. We found in this study that using green fluorescent protein (GFP) fusion constructs, the subcellular localization of HIF-2alpha was different from that of HIF-1alpha in bovine arterial endothelial cells (BAEC). HIF-1alpha was localized in the cytoplasm under normoxic cells and translocated from the cytoplasm into the nucleus in response to hypoxic induction. In contrast, HIF-2alpha was clearly localized in the nucleus of BAEC even under normoxic conditions. The regulation of HIF-2alpha might differ from that of HIF-1alpha in BAEC. We further showed that nuclear localization of HIF-2alpha was inhibited by either deletion or a single amino acid substitution within the C-terminal end of the protein. The amino acid sequence surrounding Lys737 and Arg738 functions as a nuclear localization signal of HIF-2alpha.
Hara
S
S
Department of Public Health, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Kobayashi
C
C
Imura
N
N
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001158:Arteries / Q000166:cytology; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002417:Cattle; D015687:Cell Hypoxia; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D049452:Green Fluorescent Proteins; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1