Final answer:
The hypoxia inducible factor (HIF) is a type of protein that plays a crucial role in the response to low oxygen levels in cells and tissues. It is a transcription factor that helps regulate the expression of genes involved in adaptive responses to hypoxia.
Step-by-step explanation:
The hypoxia-inducible factor (HIF) is a type of protein that plays a crucial role in the response to low oxygen levels (hypoxia) in cells and tissues. It is a transcription factor that helps regulate the expression of genes involved in adaptive responses to hypoxia.
HIF is composed of two subunits: an alpha subunit (HIF-1α, HIF-2α, or HIF-3α) and a beta subunit (HIF-1β). The alpha subunit is responsible for sensing oxygen levels and binds to the beta subunit to form the active HIF complex.
When oxygen levels are low, the alpha subunit of HIF is stabilized and translocates to the nucleus, where it binds to specific DNA sequences called hypoxia response elements (HREs). This binding promotes the transcription of target genes involved in angiogenesis, erythropoiesis, glucose metabolism, and other processes that help cells cope with hypoxia.