Uncoupling protein 1 (UCP1) is a mitochondrial inner membrane transport protein that is primarily expressed in brown adipose tissue (BAT). UCP1 dissipates the pH gradient resulting from oxidative phosphorylation, which uncouples ATP synthesis from oxidative phosphorylation and leads to the release of heat energy. As a result, UCP1 plays an important role in thermogenesis. Additional studies show possible differences in thermogenesis in individuals carrying specific polymorphisms in the corresponding UCP1 gene. Related studies link UCP1 to the possible development of obesity and type 2 diabetes.