Thermogenin

Thermogenin (called uncoupling protein by its discoverers and now known as uncoupling protein 1, or UCP1) is an uncoupling protein found in the mitochondria of brown adipose tissue (BAT). It is used to generate heat by non-shivering thermogenesis, and makes a quantitatively important contribution to countering heat loss in neonates which would otherwise occur due to the high surface area-volume ratio.