Hypoxia-inducible factor 1 (HIF-1) is a protein that plays a crucial role in how cells respond to low oxygen levels, a condition known as hypoxia. It helps regulate various genes that are involved in processes like energy production, blood vessel formation, and cell survival. By activating these genes, HIF-1 enables cells to adapt to changing oxygen availability, which is vital for maintaining healthy tissue function. HIF-1 is composed of two subunits: HIF-1α and HIF-1β. Under normal oxygen conditions, HIF-1α is rapidly degraded, but when oxygen levels drop, it stabilizes and translocates to the nucleus. There, it binds to HIF-1β and activates target genes that help the body cope with low oxygen, making HIF-1 essential for processes like wound healing and responses to exercise.