Parasites are organisms that live, at least part of their lifecycle, inside another organism (the host), which they exploit for their own benefit. Parasite infections are highly prevalent in vast tropical regions and cause a wide variety of human-neglected diseases. Significant advances have been made in the identification and characterization of selenoproteins of both major groups of human parasites: protozoan (unicellular) and helminth (worm) parasites. Some selenoprotein mRNAs had a highly efficient noncanonical form of eukaryotic SECIS element. A major finding has been the identification of the selenoprotein thioredoxin glutathione reductase (TGR) as the single redox wire for electron transfer to both thioredoxin and glutathione pathways in flatworm parasites (phylum Platyhelminthes). Further studies validated TGR as a novel drug target and identified drug leads that show great promise for treatment of flatworm infections by disrupting parasite redox homeostasis. Interestingly, lineage-specific selenoprotein families are present in medically important protozoan parasites, but are absent in their hosts.
KeywordsGlutathione Selenium Disulfide NADPH Methionine
This work was supported by PDT 63-105 grant from the Uruguayan Research Council and FIRCA-NIH Grant TW008588 to GS, NIH grant GM065204 to VNG, and PEDECIBA/ANII and CSIC postgraduate fellowships to MB.
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