Mitochondrial uncoupling proteins (UCPs), part of the mitochondrial anion carrier proteins (MACP) family, dissociate oxidative phosphorylation from ATP synthesis, releasing energy as heat. UCPs transfer anions across the mitochondrial membrane and reduce the mitochondrial membrane potential in mammalian cells. This gene, primarily expressed in skeletal muscle, encodes a protein that may protect mitochondria from lipid-induced oxidative stress. Its expression increases when fatty acid supplies exceed mitochondrial oxidation capacity, aiding in fatty acid export. UCPs contain three solcar protein domains typical of MACPs. Two splice variants of this gene have been identified.