title: The reactions catalysed by the mitochondrial uncoupling proteins UCP2 and UCP3.
abstract: The mitochondrial uncoupling proteins UCP2 and UCP3 may be important in attenuating mitochondrial production of reactive oxygen species, in insulin signalling (UCP2), and perhaps in thermogenesis and other processes. To understand their physiological roles, it is necessary to know what reactions they are able to catalyse. We critically examine the evidence for proton transport and anion transport by UCP2 and UCP3. There is good evidence that they increase mitochondrial proton conductance when activated by superoxide, reactive oxygen species derivatives such as hydroxynonenal, and other alkenals or their analogues. However, they do not catalyse proton leak in the absence of such acute activation. They can also catalyse export of fatty acid and other anions, although the relationship of anion transport to proton transport remains controversial.
authors: MRC Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, UK.
authors: Telma C
authors: TC
authors: Esteves
authors: Martin D
authors: MD
authors: Brand
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D006801:Humans; D007425:Intracellular Membranes / Q000502:physiology; D007473:Ion Channels; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D011487:Protein Conformation; D017382:Reactive Oxygen Species / Q000378:metabolism; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D002352:Carrier Proteins; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D017382:Reactive Oxygen Species; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3