In this study, a quantitative comparative proteomics approach has been used to 
analyze the Dictyostelium discoideum mitochondrial proteome variations during 
vegetative growth, starvation and the early stages of development. Application 
of 2-D DIGE technology allowed the detection of around 2000 protein spots on 
each 2-D gel with 180 proteins exhibiting significant changes in their 
expression level. In total, 96 proteins (51 unique and 45 redundant) were 
unambiguously identified. We show that the D. discoideum mitochondrial proteome 
adaptations mainly affect energy metabolism enzymes (the Krebs cycle, 
anaplerotic pathways, the oxidative phosphorylation system and energy 
dissipation), proteins involved in developmental and signaling processes as well 
as in protein biosynthesis and fate. The most striking observations were the 
opposite regulation of expression of citrate synthase and aconitase and the very 
large variation in the expression of the alternative oxidase that highlighted 
the importance of citrate and alternative oxidase in the physiology of the 
development of D. discoideum. Mitochondrial energy states measured in vivo with 
MitoTracker Orange CM Ros showed an increase in mitochondrial membrane 
polarization during D. discoideum starvation and starvation-induced development.