Cell growth and viability is compromised by oxygen deprivation (hypoxia). Hypoxia-inducible factors, including HIF-1α, HIF-1β (also designated Arnt 1), EPAS-1 (also designated HIF-2α) and HIF-3α, induce glycolysis, erythropoiesis and angiogenesis in order to restore oxygen homeostasis. Hypoxia-inducible factors are members of the Per-Arnt-Sim (PAS) domain transcription factor family. In response to hypoxia, HIF-1α is upregulated and forms a heterodimer with Arnt 1 to form the HIF-1 complex. The HIF-1 complex recognizes and binds to the hypoxia responsive element (HRE) of hypoxia-inducible genes, thereby activating transcription.Synonyms: BHLHE17, Basic-helix-loop-helix-PAS protein MOP7, Class E basic helix-loop-helix protein 17, HIF-3 alpha, Hypoxia-inducible factor 3 alpha, IPAS, Inhibitory PAS domain protein, MOP7, Member of PAS protein 7, PASD7