Dual targeting of antioxidant and metabolic enzymes to the mitochondrion and the apicoplast of Toxoplasma gondii.

Autor: Paco Pino, Bernardo Javier Foth, Lai-Yu Kwok, Lilach Sheiner, Rebecca Schepers, Thierry Soldati, Dominique Soldati-Favre
Jazyk: angličtina
Rok vydání: 2007
Předmět:
Zdroj: PLoS Pathogens, Vol 3, Iss 8, p e115 (2007)
Druh dokumentu: article
ISSN: 1553-7366
1553-7374
DOI: 10.1371/journal.ppat.0030115
Popis: Toxoplasma gondii is an aerobic protozoan parasite that possesses mitochondrial antioxidant enzymes to safely dispose of oxygen radicals generated by cellular respiration and metabolism. As with most Apicomplexans, it also harbors a chloroplast-like organelle, the apicoplast, which hosts various biosynthetic pathways and requires antioxidant protection. Most apicoplast-resident proteins are encoded in the nuclear genome and are targeted to the organelle via a bipartite N-terminal targeting sequence. We show here that two antioxidant enzymes-a superoxide dismutase (TgSOD2) and a thioredoxin-dependent peroxidase (TgTPX1/2)-and an aconitase are dually targeted to both the apicoplast and the mitochondrion of T. gondii. In the case of TgSOD2, our results indicate that a single gene product is bimodally targeted due to an inconspicuous variation within the putative signal peptide of the organellar protein, which significantly alters its subcellular localization. Dual organellar targeting of proteins might occur frequently in Apicomplexans to serve important biological functions such as antioxidant protection and carbon metabolism.
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