title: Canine mitochondrial uncoupling proteins: structure and mRNA expression of three isoforms in adult beagles.
abstract: Uncoupling proteins (UCPs) are members of the mitochondrial transporter family that dissipate the proton gradient as heat more than via ATP synthesis. In the present study, nucleotide and amino acid sequences of UCPs 1, 2 and 3 of a dog were determined, and their mRNA expression in various peripheral tissues was examined. The sequences were highly (76-97%) homologous to those of other species. Although lower homologies (60-74%) were found when compared among the three canine UCPs, their deduced amino acid sequences had some common domains, such as three mitochondrial carrier protein motifs, six transmembrane alpha-helix domains, and putative purine nucleotide binding domains. By Northern blot analyses, UCP1 mRNA was not detected in any tissues examined. UCP2 mRNA was expressed in most tissues, particularly abundantly in adipose tissue, spleen and lung. Two sizes of UCP3 mRNA were found exclusively in heart and skeletal muscle. These results suggest that canine UCPs have uncoupling activity, and are involved in the regulation of metabolic heat production and/or energy expenditure, as do those of other species.
authors.affiliation: Laboratory of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, 060-0818, Sapporo, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Ishioka
authors.forename: Katsushi
authors.initials: K
authors.lastname: Kanehira
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Sasaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saito
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004285:Dogs / Q000378:metabolism*; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D020033:Protein Isoforms; D011506:Proteins; D012333:RNA, Messenger; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3