Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochemical Journal Année : 2006

Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes

R. Luise Krauth-Siegel
  • Fonction : Auteur
Leopold Flohé
  • Fonction : Auteur

Résumé

In trypanosomes, the thioredoxin-type protein tryparedoxin is a multi-purpose oxidoreductase that is involved in the detoxification of hydroperoxides, the synthesis of DNA precursors and the replication of the kinetoplastid DNA. African trypanosomes possess two isoforms that are localized in the cytosol and in the mitochondrion of the parasites, respectively. Here we report on the biological significance of the cytosolic tryparedoxin of Trypanosoma brucei for hydroperoxide detoxification. Depending on the growth phase, the concentration of the protein is 3- to 7-fold higher in the parasite form infecting mammals (50-100 microM) than in the form hosted by the tse-tse fly (7-34 microM). Depletion of the mRNA in bloodstream trypanosomes by RNA interference revealed the indispensability of the protein. Proliferation and viability of cultured trypanosomes were impaired when tryparedoxin was lowered to 1 microM for more than 48 h. Although the levels of glutathione, glutathionylspermidine and trypanothione were 2 to 3.5-fold increased, the sensitivity against exogenously generated hydrogen peroxide was significantly enhanced. The results prove the essential role of the cytosolic tryparedoxin and its pivotal function in the parasite defense against oxidative stress.

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Dates et versions

hal-00478658 , version 1 (30-04-2010)

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Marcelo Alberto Comini, R. Luise Krauth-Siegel, Leopold Flohé. Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes. Biochemical Journal, 2006, 402 (1), pp.43-49. ⟨10.1042/BJ20061341⟩. ⟨hal-00478658⟩

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