scholarly journals No mitochondrial uncoupling artefact is caused by expression of uncoupling protein 1 in a mammalian cell culture: A new system to study mitochondrial carrier proteins

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Martin Jastroch ◽  
Verena Hirschberg ◽  
Martin Klingenspor
2001 ◽  
Vol 356 (3) ◽  
pp. 779-789 ◽  
Author(s):  
Jeff A. STUART ◽  
James A. HARPER ◽  
Kevin M. BRINDLE ◽  
Mika B. JEKABSONS ◽  
Martin D. BRAND

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 UCP1homologues UCP2 and UCP3. Yeast expressing UCP1 at modest levels (approx. 1μg/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. 11μg/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 UCP1homologues are verified by their ability to uncouple yeast mitochondria.


2012 ◽  
Vol 59 (1) ◽  
Author(s):  
Mohd Helmi Sani ◽  
Frank Baganz

At present, there are a number of commercial small scale shaken systems available on the market with instrumented controllable microbioreactors such as Micro–24 Microreactor System (Pall Corporation, Port Washington, NY) and M2P Biolector, (M2P Labs GmbH, Aachen, Germany). The Micro–24 system is basically an orbital shaken 24–well plate that operates at working volume 3 – 7 mL with 24 independent reactors (deep wells, shaken and sparged) running simultaneously. Each reactor is designed as single use reactor that has the ability to continuously monitor and control the pH, DO and temperature. The reactor aeration is supplied by sparging air from gas feeds that can be controlled individually. Furthermore, pH can be controlled by gas sparging using either dilute ammonia or carbon dioxide directly into the culture medium through a membrane at the bottom of each reactor. Chen et al., (2009) evaluated the Micro–24 system for the mammalian cell culture process development and found the Micro–24 system is suitable as scaledown tool for cell culture application. The result showed that intra-well reproducibility, cell growth, metabolites profiles and protein titres were scalable with 2 L bioreactors.


2000 ◽  
Vol 20 (7) ◽  
pp. 2488-2497 ◽  
Author(s):  
Sabrina D. Dyall ◽  
Carla M. Koehler ◽  
Maria G. Delgadillo-Correa ◽  
Peter J. Bradley ◽  
Evelyn Plümper ◽  
...  

ABSTRACT A number of microaerophilic eukaryotes lack mitochondria but possess another organelle involved in energy metabolism, the hydrogenosome. Limited phylogenetic analyses of nuclear genes support a common origin for these two organelles. We have identified a protein of the mitochondrial carrier family in the hydrogenosome ofTrichomonas vaginalis and have shown that this protein, Hmp31, is phylogenetically related to the mitochondrial ADP-ATP carrier (AAC). We demonstrate that the hydrogenosomal AAC can be targeted to the inner membrane of mitochondria isolated from Saccharomyces cerevisiae through the Tim9-Tim10 import pathway used for the assembly of mitochondrial carrier proteins. Conversely, yeast mitochondrial AAC can be targeted into the membranes of hydrogenosomes. The hydrogenosomal AAC contains a cleavable, N-terminal presequence; however, this sequence is not necessary for targeting the protein to the organelle. These data indicate that the membrane-targeting signal(s) for hydrogenosomal AAC is internal, similar to that found for mitochondrial carrier proteins. Our findings indicate that the membrane carriers and membrane protein-targeting machinery of hydrogenosomes and mitochondria have a common evolutionary origin. Together, they provide strong evidence that a single endosymbiont evolved into a progenitor organelle in early eukaryotic cells that ultimately give rise to these two distinct organelles and support the hydrogen hypothesis for the origin of the eukaryotic cell.


In Vitro ◽  
1973 ◽  
Vol 8 (5) ◽  
pp. 375-378 ◽  
Author(s):  
Arthur H. Intosh ◽  
K. Maramorosch ◽  
C. Rechtoris

1999 ◽  
Vol 34 (2) ◽  
pp. 159-165 ◽  
Author(s):  
J. Feuser ◽  
M. Halfar ◽  
D. Lütkemeyer ◽  
N. Ameskamp ◽  
M.-R. Kula ◽  
...  

1983 ◽  
Vol 1 (4) ◽  
pp. 102-108 ◽  
Author(s):  
M.W. Glacken ◽  
R.J. Fleischaker ◽  
A.J. Sinskey

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