Sequence determinants in hypoxia-inducible factor-1alpha for hydroxylation by the prolyl hydroxylases PHD1, PHD2, and PHD3.
Hypoxia-inducible factor (HIF) is a heterodimeric transcription factor induced by hypoxia. Under normoxic conditions, site-specific proline hydroxylation of the alpha subunits of HIF allows recognition by the von Hippel-Lindau tumor suppressor protein (VHL), a component of an E3 ubiquitin ligase complex that targets these subunits for degradation by the ubiquitin-proteasome pathway. Under hypoxic conditions, this hydroxylation is inhibited, allowing the alpha subunits of HIF to escape VHL-mediated degradation. Three enzymes, prolyl hydroxylase domain-containing proteins 1, 2, and 3 (PHD1, -2, and -3; also known as HIF prolyl hydroxylase 3, 2, and 1, respectively), have recently been identified that catalyze proline hydroxylation of HIF alpha subunits. These enzymes hydroxylate specific prolines in HIF alpha subunits in the context of a strongly conserved LXXLAP sequence motif (where X indicates any amino acid and P indicates the hydroxylacceptor proline). We report here that PHD2 has the highest specific activity toward the primary hydroxylation site of HIF-1alpha. Furthermore, and unexpectedly, mutations can be tolerated at the -5, -2, and -1 positions (relative to proline) of the LXXLAP motif. Thus, these results provide evidence that the only obligatory residue for proline hydroxylation in HIF-1alpha is the hydroxylacceptor proline itself.
Huang
Jianhe
J
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
Zhao
Quan
Q
Mooney
Sharon M
SM
Lee
Frank S
FS
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005799:Genes, Dominant; D006900:Hydroxylation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism*; D011392:Proline / Q000737:chemistry; D011485:Protein Binding; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C085984:PHD1 protein, S cerevisiae; D010455:Peptides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011392:Proline; D011393:Procollagen-Proline Dioxygenase