The first uncoupling protein discovered, UCP1, was discovered in the brown adipose tissues of hibernators and small rodents, which provide non-shivering heat to these animals. These brown adipose tissues are essential to maintaining the body temperature of small rodents, and studies with (UCP1)-knockout mice show that these tissues do not function correctly without functioning uncoupling proteins. In fact, these studies revealed that cold-acclimation is not possible for these knockout mice, indicating that UCP1 is an essential driver of heat production in these brown adipose tissues.
Elsewhere in the body, uncoupling protein activities are known to affect the temperature in micro-environments. This is believed to affect other proteins' activity in these regions, though work is still required to determine the true consequences of uncoupling-induced temperature gradients within cells.
The structure of human uncoupling protein 1 UCP1 has been solved by cryogenic-electron microscopy. The structure has the typical fold of a member of the SLC25 family. UCP1 is locked in a cytoplasmic-open state by guanosine triphosphate in a pH-dependent manner.