title: Differential function of the prolyl hydroxylases PHD1, PHD2, and PHD3 in the regulation of hypoxia-inducible factor.
abstract: Hypoxia-inducible factor (HIF) is a transcriptional regulator that plays a key role in many aspects of oxygen homeostasis. The heterodimeric HIF complex is regulated by proteolysis of its alpha-subunits, following oxygen-dependent hydroxylation of specific prolyl residues. Although three HIF prolyl hydroxylases, PHD1, PHD2, and PHD3, have been identified that have the potential to catalyze this reaction, the contribution of each isoform to the physiological regulation of HIF remains uncertain. Here we show using suppression by small interference RNA that each of the three PHD isoforms contributes in a non-redundant manner to the regulation of both HIF-1alpha and HIF-2alpha subunits and that the contribution of each PHD under particular culture conditions is strongly dependent on the abundance of the enzyme. Thus in different cell types, isoform-specific patterns of PHD induction by hypoxia and estrogen alter both the relative abundance of the PHDs and their relative contribution to the regulation of HIF. In addition, the PHDs manifest specificity for different prolyl hydroxylation sites within each HIF-alpha subunit, and a degree of selectively between HIF-1alpha and HIF-2alpha isoforms, indicating that differential PHD inhibition has the potential to selectively alter the characteristics of HIF activation.
authors.affiliation: Henry Wellcome Bldg. of Genomic Medicine, Roosevelt Drive, Headington, Oxford, UK.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Appelhoff
authors.forename: Ya-Min
authors.initials: YM
authors.lastname: Tian
authors.forename: Raju R
authors.initials: RR
authors.lastname: Raval
authors.forename: Helen
authors.initials: H
authors.lastname: Turley
authors.forename: Adrian L
authors.initials: AL
authors.lastname: Harris
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Pugh
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ratcliffe
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gleadle
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002384:Catalysis; D002460:Cell Line; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology*; D049308:Dioxygenases; D004958:Estradiol / Q000494:pharmacology; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D000860:Hypoxia; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D017874:Immediate-Early Proteins / Q000502:physiology*; D015151:Immunoblotting; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009687:Nuclear Proteins / Q000378:metabolism* / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000502:physiology*; D020033:Protein Isoforms; D012313:RNA / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D012680:Sensitivity and Specificity; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D049308:Dioxygenases; D004958:Estradiol; D005982:Glutathione Transferase; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D017874:Immediate-Early Proteins; D009687:Nuclear Proteins; D010100:Oxygen; D011393:Procollagen-Proline Dioxygenase; D020033:Protein Isoforms; D012313:RNA; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D012260:Ribonucleases; D015534:Trans-Activators; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human; C497443:Hif1a protein, mouse; C490190:EGLN1 protein, human; C447780:EGLN2 protein, human; C488894:EGLN3 protein, human; C490189:Egln1 protein, mouse