Assessment of uncoupling activity of uncoupling protein 3 using a yeast heterologous expression system.
Uncoupling protein 3L, uncoupling protein 1 and the mitochondrial oxoglutarate carrier were expressed in Saccharomyces cerevisae. Effects on different parameters related to the energy expenditure were studied. Both uncoupling protein 3L and uncoupling protein 1 reduced the growth rate by 49% and 32% and increased the whole yeast O2 consumption by 31% and 19%, respectively. In isolated mitochondria, uncoupling protein 1 increased the state 4 respiration by 1.8-fold, while uncoupling protein 3L increased the state 4 respiration by 1.2-fold. Interestingly, mutant uncoupling protein 1 carrying the H145Q and H147N mutations, previously shown to markedly decrease the H+ transport activity of uncoupling protein 1 when assessed using a proteoliposome system (Bienengraeber et al. (1998) Biochem. 37, 3-8), uncoupled the mitochondrial respiration to almost the same degree as wild-type uncoupling protein 1. Thus, absence of this histidine pair in uncoupling protein 2 and uncoupling protein 3 does not by itself rule out the possibility that these carriers have an uncoupling function. The oxoglutarate carrier had no effect on any of the studied parameters. In summary, a discordance exists between the magnitude of effects of uncoupling protein 3L and uncoupling protein 1 in whole yeast versus isolated mitochondria, with uncoupling protein 3L having greater effects in whole yeast and a smaller effect on the state 4 respiration in isolated mitochondria. These findings suggest that uncoupling protein 3L, like uncoupling protein 1, has an uncoupling activity. However, the mechanism of action and/or regulation of the activity of uncoupling protein 3L is likely to be different.
Zhang
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CY
Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
Hagen
T
T
Mootha
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VK
Slieker
L J
LJ
Lowell
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BB
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D010101:Oxygen Consumption; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development; D000071256:Uncoupling Protein 1; D000071247:Uncoupling Protein 3
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011994:Recombinant Proteins; C000604371:UCP1 protein, human; C000604392:UCP3 protein, human; C000604373:Ucp1 protein, rat; C000604394:Ucp3 protein, rat; D000071256:Uncoupling Protein 1; D000071247:Uncoupling Protein 3; C021723:oxoglutarate translocator