Two isoforms of a divalent metal transporter (DMT1) in Schistosoma mansoni suggest a surface-associated pathway for iron absorption in schistosomes

Smyth, D. J. , Glanfield, A., McManus, D. P., Hacker, E., Blair, D., Anderson, G. J. and Jones, M. K. (2006) Two isoforms of a divalent metal transporter (DMT1) in Schistosoma mansoni suggest a surface-associated pathway for iron absorption in schistosomes. Journal of Biological Chemistry, 281(4), pp. 2242-2248. (doi: 10.1074/jbc.M511148200) (PMID:16267047) (PMCID:PMC1459476)

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Abstract

We describe two homologues of the mammalian divalent metal transporter (DMT1) for Schistosoma mansoni, a pathogenic intravascular parasite of humans. Schistosomes have a high nutritional and metabolic demand for iron. Nucleotide sequences of the parasite homologues, designated SmDMT1A and -B, are identical in all but the 5′-regions. The predicted amino acid sequences share at least 60% identity with DMT1 (=Nramp2) of humans, mice, and rats, and at least 55% identity with Nramp1 from mice, humans and Caenorhabditis elegans. SmDMT1A is expressed in differentiating eggs, miracidia, cercariae, schistosomula, and adults, whereas SmDMT1B is expressed in all but the miracidium and occurs at lower levels than SmDMT1A in differentiating eggs and cercariae. An iron-responsive element, present at the 3′-untranslated region of many DMT1 molecules, is not present in schistosome mRNAs studied here. A Western blot analysis of adult worm preparations using a homologous rabbit serum raised against a schistosome DMT1 peptide and a heterologous serum raised against mammalian DMT1, revealed a band approximating 115 kDa. By immunofluorescence microscopy, the schistosome DMT1s localize primarily to the tegument. Iron uptake assays demonstrated that SmDMT1s were able to rescue yeast growth in ferrous iron-transport deficient yeast (fet3fet4). The results suggest that schistosomes express molecules for ferrous iron transport in their tegument, suggesting trans-tegumental transport as one means of iron acquisition for these parasites.

Item Type:Articles
Additional Information:This work was supported in part by grants from the National Health and Medical Research Council (NHMRC), Wellcome Trust, and the Australian Research Council. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Smyth, Dr Danielle
Authors: Smyth, D. J., Glanfield, A., McManus, D. P., Hacker, E., Blair, D., Anderson, G. J., and Jones, M. K.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN:0021-9258
ISSN (Online):1083-351X
Published Online:02 November 2005

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