HIF-1, O2, and the 3 PHDs: How Animal Cells Signal Hypoxia to the Nucleus

Hypoxia-inducible factor 1 (HIF-1) is a global regulator of cellular and systemic O2 homeostasis in animals. A molecular basis for O2-regulated expression of the HIF-1α subunit has now been determined, providing a mechanism for changes in gene expression in response to changes in cellular oxygenation.