Contributions of studies on uncoupling proteins to research on metabolic diseases.
The coupling of O2 consumption to ADP phosphorylation in mitochondria is partial. This is particularly obvious in brown adipocyte mitochondria which use a regulated uncoupling mechanism generating heat production from substrate oxidation, and catalysing thermogenesis in rodents or infants in response to cold, and arousing hibernators. In the case of brown adipose tissue, the uncoupling mechanism is related to a specific protein in the inner mitochondrial membrane referred to as UCP1. Although the biological importance of UCP1 in human adults is not demonstrated, genetic analysis of various human cohorts suggested a participation of UCP1 to control of fat content and body weight. Very recently, the cloning of UCP2 and UCP3, two homologues of UCP1, has renewed the field of research on the importance of respiration control in metabolic processes and metabolic diseases. UCP2 is widely expressed in organs, whereas UCP3 is mainly present in muscles. These proteins may explain why the coupling of respiration to ADP phosphorylation is less than perfect. Their biological importance should be studied. They also represent new putative targets for drugs against metabolic diseases such as obesity.
Centre National de la Recherche Scientifique, Centre de Recherche sur l'Endocrinologie Molećulaire et le Développement, Meudon, France. ricquier@infobiogen.fr
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D017667:Adipocytes / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism; D006801:Humans; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008659:Metabolic Diseases / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C000604371:UCP1 protein, human; C000604389:UCP2 protein, human; C000604392:UCP3 protein, human; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3