Abstract
Uncoupling proteins (UCPs) are inner mitochondrial membrane transporters which dissipate the proton gradient, releasing stored energy as heat. UCP1 is expressed exclusively in brown adipocytes while UCP2 is expressed widely. We now report the molecular cloning of a third uncoupling protein homologue, designated UCP3. At the amino acid level, hUCP3 is 71% identical to hUCP2 and 57% identical to hUCP1. UCP3 is distinguished from UCP1 and UCP2 by its abundant and preferential expression in skeletal muscle in humans, and brown adipose tissue and skeletal muscle in rodents. Since skeletal muscle and brown adipose tissue are believed to be important sites for regulated energy expenditure in humans and rodents, respectively, UCP3 may be an important mediator of adaptive thermogenesis. Since UCP3 is minimally expressed in human heart and other critical organs, it is a promising target for anti-obesity drug development aimed at increasing thermogenesis.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adipose Tissue, Brown / metabolism*
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Amino Acid Sequence
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Blotting, Northern
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Carrier Proteins / biosynthesis
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism
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Cloning, Molecular
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Gene Expression Regulation
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Humans
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Ion Channels
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Membrane Proteins / chemistry
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Membrane Proteins / metabolism
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Membrane Transport Proteins*
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Mitochondria / metabolism*
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Mitochondrial Proteins*
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Molecular Sequence Data
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Muscle, Skeletal / metabolism*
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Proteins / chemistry
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Proteins / metabolism
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RNA, Messenger / metabolism
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Sequence Homology, Amino Acid
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Uncoupling Protein 1
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Uncoupling Protein 2
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Uncoupling Protein 3
Substances
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Carrier Proteins
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Ion Channels
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Membrane Proteins
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Membrane Transport Proteins
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Mitochondrial Proteins
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Proteins
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RNA, Messenger
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UCP1 protein, human
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UCP2 protein, human
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UCP3 protein, human
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Uncoupling Protein 1
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Uncoupling Protein 2
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Uncoupling Protein 3