Uncoupling protein and alternative oxidase of Dictyostelium discoideum: occurrence, properties and protein expression during vegetative life and starvation-induced early development.
In this study we show that mitochondria of Dictyostelium discoideum contain both alternative oxidase (AOX) and uncoupling protein (UCP). AOX was stimulated by purine mononucleoside and was monomeric. UCP was stimulated by free fatty acids and was poorly sensitive to GTP. Both proteins collaborated in energy dissipation when activated together. AOX expression in free-living ameboid cells decreased strongly from exponential to stationary phase of growth but much less during starvation-induced aggregation. In contrast, UCP expression was constant in all conditions indicating permanent need. Our results suggest that AOX could play a role in cell differentiation, mainly by protecting prespore cells from programmed cell death.
Jarmuszkiewicz
Wieslawa
W
Department of Bioenergetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Fredry 10, 61-701, Poznan, Poland.
Behrendt
Maciej
M
Navet
Rachel
R
Sluse
Francis E
FE
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002455:Cell Division; D004023:Dictyostelium / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000378:metabolism; D006157:Guanosine Monophosphate / Q000378:metabolism; D006859:Hydrogen; D015151:Immunoblotting; D007473:Ion Channels; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D010940:Plant Proteins; D013816:Thermodynamics; D013997:Time Factors; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase
D002352:Carrier Proteins; D005227:Fatty Acids; D006157:Guanosine Monophosphate; D006859:Hydrogen; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase