UCP5/BMCP1 transcript isoforms in human skeletal muscle: relationship of the short-insert isoform with lipid oxidation and resting metabolic rates.
Uncoupling protein 5 (UCP5) or brain mitochondrial carrier protein-1 (BMCP1) enhances mitochondrial proton leak in vitro and its hepatic and brain expression profiles are modulated by diet and cold exposure in mice. Alternative splicing generates three isoforms: a long form (UCP5L), a short form (UCP5S), and a short form with a 31 amino acid insert (UCP5SI). We investigated the relationship between skeletal muscle UCP5 expression and in vivo energy metabolism in 36 non-diabetic Pima Indians. We determined the expression levels of total UCP5 (UCP5T), and the isoforms UCP5L, UCP5S, and UCP5SI (66.8, 32.5, and 0.8% of UCP5T, respectively). None correlated with body weight or percent body fat. The transcript level of UCP5SI, but not the others, was positively correlated with resting metabolic rate (r=0.38, P=0.02, adjusted for age, sex, fat mass, and fat-free mass) and lipid oxidation rate (adjusted for age, sex, and percent body fat) during a euglycemic clamp with infusion of insulin at a physiologic concentration (r=0.42, P=0.01).
Yang
Xiaolin
X
Clinical Diabetes and Nutrition Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ 85016, USA.
Pratley
Richard E
RE
Tokraks
Stephen
S
Tataranni
P Antonio
PA
Permana
Paska A
PA
D000293:Adolescent; D000328:Adult; D044466:Asian People; D001481:Basal Metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007198:Indians, North American; D007328:Insulin / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D026901:Membrane Transport Proteins; D000071245:Mitochondrial Uncoupling Proteins; D018482:Muscle, Skeletal / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D002352:Carrier Proteins; D007328:Insulin; D026901:Membrane Transport Proteins; D000071245:Mitochondrial Uncoupling Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; C116584:SLC25A14 protein, human