The hypoxia inducible factor (HIF) is a transcriptional complex that is involved in oxygen homeostasis [5]. At normal oxygen levels, the alpha subunit of HIF (HIF-1α) is targeted for degradation by prolyl hydroxylation by the PHD proteins 1-3 (HIF-PHs) whch are 2-oxoglutarate (2OG) oxygenases responsible for the post-translational modification of a specific proline in each of the oxygen-dependent degradation (ODD) domains of HIF-1α. Hydroxylated HIFs are then targeted for proteasomal degradation via the von Hippel-Lindau ubiquitination complex [4]. Under hypoxic conditions, the hydroxylation reaction is blunted which results in decreased HIF degradation. The surviving HIFs are then available to translocate to the nucleus where they heterodimerize with HIF-1β, effecting increased expression of hypoxia-inducible genes.
HIF-PH enzymes are being investigated as pharmacological targets as their inhibition mimics the hypoxic state and switches on transcription of genes associated with processes such as erythropoiesis and vasculogenesis [3]. Small molecule HIF-PH inhibitors are in clinical trial as novel therapies for the amelioration of anemia associated with chronic kidney disease [1].

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