Mechanism and evolution of the uncoupling protein of brown adipose tissue.

The uncoupling protein found in mitochondria from thermogenic brown adipose tissue is structurally very similar to two other mitochondrial carrier proteins transporting ADP/ATP and phosphate, respectively. Similarities are also seen with the mechanism of these carriers, which are part of a family of H+/OH(-)-substrate anion co-transporters, further strengthening the evidence that the uncoupling protein has evolved from this family of mitochondrial carrier proteins.