Hypoxia-inducible factor (HIF) is a DNA-binding protein that regulates homeostasis via transcription of a wide range of genes. It is inactive in oxygenated cells, but becomes active in hypoxic, i.e. low oxygen conditions. HIF proteins consist of a heterodimeric complex of identical alpha and beta sub-units. The α is degraded in normal oxygen conditions, while the β remains independent of O2 concentration.
