The metabolic roles of the endosymbiotic organelles of Toxoplasma and Plasmodium spp.
L Sheiner, AB Vaidya, GI McFadden - Current opinion in microbiology, 2013 - Elsevier
L Sheiner, AB Vaidya, GI McFadden
Current opinion in microbiology, 2013•ElsevierHighlights•Toxoplasma and Plasmodium possess two organelles of endosymbiotic origin:
the apicoplast, and the mitochondrion.•The mitochondrion hosts a complete TCA cycle and
an electron transport chain lacking complex I. Glutamine catabolism contributes to the TCA
cycle.•Haem biosynthesis is an extremely unusual chimerical pathway shared between the
two organelles and the cytoplasm.•Isoprenoid precursor synthesis and fatty acid synthesis
are essential roles of the apicoplast. Different life stages show differential dependencies on …
the apicoplast, and the mitochondrion.•The mitochondrion hosts a complete TCA cycle and
an electron transport chain lacking complex I. Glutamine catabolism contributes to the TCA
cycle.•Haem biosynthesis is an extremely unusual chimerical pathway shared between the
two organelles and the cytoplasm.•Isoprenoid precursor synthesis and fatty acid synthesis
are essential roles of the apicoplast. Different life stages show differential dependencies on …
Highlights
- Toxoplasma and Plasmodium possess two organelles of endosymbiotic origin: the apicoplast, and the mitochondrion.
- The mitochondrion hosts a complete TCA cycle and an electron transport chain lacking complex I. Glutamine catabolism contributes to the TCA cycle.
- Haem biosynthesis is an extremely unusual chimerical pathway shared between the two organelles and the cytoplasm.
- Isoprenoid precursor synthesis and fatty acid synthesis are essential roles of the apicoplast. Different life stages show differential dependencies on these pathways.
The apicoplast and the mitochondrion of Apicomplexa cooperate in providing essential metabolites. Their co-evolution during the ancestral acquisition of a plastid and subsequent loss of photosynthesis resulted in divergent metabolic pathways compared with mammals and plants. This is most evident in their chimerical haem synthesis pathway.
Toxoplasma and Plasmodium mitochondria operate canonical tricarboxylic acid (TCA) cycles and electron transport chains, although the roles differ between Toxoplasma tachyzoites and Plasmodium erythrocytic stages. Glutamine catabolism provides TCA intermediates in both parasites.
Isoprenoid precursor synthesis is the only essential role of the apicoplast in Plasmodium erythrocytic stages. An apicoplast-located fatty acid synthesis is dispensable in these stages, which instead predominantly salvage fatty acids, while in Plasmodium liver stages and in Toxoplasma tachyzoites fatty acid synthesis is an essential role of the plastid.
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