Endogenous mutations in human uncoupling protein 3 alter its functional properties.

Human uncoupling protein (UCP3) is a mitochondrial transmembrane carrier that uncouples oxidative phosphorylation and is a candidate gene for obesity. Expression of native human UCP3 mutations in yeast showed complete loss (R70W), significant reduction (R143X), or no effect (V102I and IVS6+1G > A) on the uncoupling activity of UCP3. It is concluded that certain mutations in UCP3 alter its functional impact on membrane potential (deltaphi), possibly conferring susceptibility to develop metabolic diseases.