The von Hippel-Lindau protein, HIF hydroxylation, and oxygen sensing.

The heterodimeric transcription factor HIF (hypoxia-inducible factor), consisting of a labile alpha-subunit and a stable beta-subunit, is a master regulator of genes involved in acute or chronic adaptation to low oxygen. Studies performed over the past 5 years revealed that HIFalpha-subunits are enzymatically hydroxylated in an oxygen-dependent manner. Hydroxylation of either of two conserved prolyl residues targets HIFalpha for destruction by a ubiquitin ligase containing the von Hippel-Lindau tumor suppressor protein whereas hydroxylation on a C-terminal asparagine affects HIF transactivation function. Pharmacological manipulation of HIF activity might be beneficial in diseases characterized by abnormal tissue oxygenation including myocardial infarction, cerebrovascular disease, and cancer.