Differential function of the prolyl hydroxylases PHD1, PHD2, and PHD3 in the regulation of hypoxia-inducible factor.

Journal article

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: Appelhoff, R; Tian, Y; Raval, R; Turley, H; Harris, A

• Publication status: Published
• Journal: Journal of biological chemistry
• Volume: 279
• Issue: 37
• Pages: 38458-38465
• Publication date: 2004-09-01
• DOI: 10.1074/jbc.m406026200
• EISSN: 1083-351X
• ISSN: 0021-9258
• Language: English
• Keywords: Cell Line; Animals; Dioxygenases; Ribonucleases; Anoxia; Mice, Inbred BALB C; Mice; DNA-Binding Proteins; Estradiol; RNA; Nuclear Proteins; RNA, Small Interfering; Hypoxia-Inducible Factor 1; Immunoblotting; Sensitivity and Specificity; Hypoxia-Inducible Factor 1, alpha Subunit; Basic Helix-Loop-Helix Transcription Factors; Immediate-Early Proteins; Protein Isoforms; Transcription Factors; Kinetics; Recombinant Fusion Proteins; Procollagen-Proline Dioxygenase; Trans-Activators; Catalysis; Glutathione Transferase; Plasmids; Oxygen; Humans; Cell Line, Tumor; Gene Expression Regulation; RNA, Messenger