A mitochondrial uncoupling artifact can be caused by expression of uncoupling protein 1 in yeast.

TitleA mitochondrial uncoupling artifact can be caused by expression of uncoupling protein 1 in yeast.
Publication TypeJournal Article
Year of Publication2001
AuthorsStuart, JA, Harper, JA, Brindle, KM, Jekabsons, MB, Brand, MD
JournalBiochem J
Volume356
IssuePt 3
Pagination779-89
Date Published2001 Jun 15
ISSN0264-6021
KeywordsAnimals, Artifacts, Blotting, Western, Carrier Proteins, Cloning, Molecular, Ion Channels, Membrane Proteins, Mice, Mitochondrial Proteins, Recombinant Proteins, Saccharomyces cerevisiae, Uncoupling Protein 1
Abstract

Uncoupling protein 1 (UCP1) from mouse was expressed in yeast and the specific (GDP-inhibitable) and artifactual (GDP-insensitive) effects on mitochondrial uncoupling were assessed. UCP1 provides a GDP-inhibitable model system to help interpret the uncoupling effects of high expression in yeast of other members of the mitochondrial carrier protein family, such as the UCP1 homologues UCP2 and UCP3. Yeast expressing UCP1 at modest levels (approx. 1 microg/mg of mitochondrial protein) showed no growth defect, normal rates of chemically uncoupled respiration and an increased non-phosphorylating proton conductance that was completely GDP-sensitive. The catalytic-centre activity of UCP1 in these yeast mitochondria was similar to that in mammalian brown-adipose-tissue mitochondria. However, yeast expressing UCP1 at higher levels (approx. 11 microg/mg of mitochondrial protein) showed a growth defect. Their mitochondria had depressed chemically uncoupled respiration rates and an increased proton conductance that was partly GDP-insensitive. Thus, although UCP1 shows native behaviour at modest levels of expression in yeast, higher levels (or rates) of expression can lead to an uncoupling that is not a physiological property of the native protein and is therefore artifactual. This observation might be important in the interpretation of results from experiments in which the functions of UCP1 homologues are verified by their ability to uncouple yeast mitochondria.

DOI10.1042/0264-6021:3560779
Alternate JournalBiochem. J.
Citation Key10.1042/0264-6021:3560779
PubMed ID11389685
PubMed Central IDPMC1221904