UCP2 is expressed on many different tissues including the kidney, liver, GI tract, brain, and skeletal muscle and they 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. They also reduce the mitochondrial membrane potential in mammalian cells, which reduces production of reactive oxygen species (ROS). 
