UCP2, which is expressed on many different organs including the kidney, liver, GI tract, brain, and skeletal muscle, separate, or uncouple, oxidative phosphorylation from ATP synthesis by dissipating the mitochondrial membrane potential as heat and they reduce the mitochondrial membrane potential in mammalian cells, which reduces production of reactive oxygen species (ROS).
UCPs separate, or uncouple, oxidative phosphorylation from ATP synthesis by dissipating the mitochondrial membrane potential as heat, also referred to as the mitochondrial proton leak. They also reduce the mitochondrial membrane potential in mammalian cells, which reduces production of reactive oxygen species (ROS). In contrast to UCP1 and UCP3, which are primarily expressed in adipose and smooth muscle, UCP2 is expressed on many different tissues including the kidney, liver, GI tract, brain, and skeletal muscle. 
