Mitochondrial proteomics of Drosophila melanogaster expressing the alternative oxidase under different dietary conditions

Abstract

The alternative oxidase (AOX) is part of an alternative pathway of electron transport in the mitochondrial respiratory chain that bypasses the cytochrome c axis, promoting oxygen consumption, and therefore decreasing the amount of reactive oxygen species resulted from the respiration process. When expressed in lines of Drosophila melanogaster with neurological and mitochondrial dysfunctions, AOX performed satisfactorily, showing significant decrease of the deleterious phenotype associated with these lines. Because AOX is unable to pump protons into the mitochondrial intermembrane space, its presence theoretically leads to a lower electrochemical potential and a consequent decrease in ATP production. This suggests that when the AOX enzyme is expressed, anaerobic glycolysis has an important role in compensating the lower mitochondrial ATP production. The data obtained from culturing these flies under different dietary conditions showed that there was an 80% decrease in the eclosion rate when a carbohydrate-restricted diet was used. Thus, to analyze in detail this negative effect of AOX in nutritional stress condition, the study of mitochondrial proteomics will be carried out, aiming at unraveling the molecular nature of the development defect provided by AOX in these conditions. In addition, additional developmental assays will be performed to understand if only the presence of AOX is the cause of the observed phenotype or if the expression of AOX in specific tissues such as muscles and neurons are capable of compromising the eclosion rate of these flies when submitted to carbohydrate-restricted diet. (AU)