Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-36670
Faghiri, Z; Camargo, S M R; Huggel, K; Forster, I C; Ndegwa, D; Verrey, F; Skelly, P J (2010). The tegument of the human parasitic worm Schistosoma mansoni as an excretory organ: the surface aquaporin SmAQP is a lactate transporter. PLoS ONE, 5(5):e10451.
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Adult schistosomes are intravascular parasites that metabolize imported glucose largely via glycolysis. How the parasites get rid of the large amounts of lactic acid this generates is unknown at the molecular level. Here, we report that worms whose aquaporin gene (SmAQP) has been suppressed using RNAi fail to rapidly acidify their culture medium and excrete less lactate compared to controls. Functional expression of SmAQP in Xenopus oocytes demonstrates that this protein can transport lactate following Michaelis-Menten kinetics with low apparent affinity (Km = 41+/-5. 8 mM) and with a low energy of activation (E(a) = 7.18+/-0.7 kcal/mol). Phloretin, a known inhibitor of lactate release from schistosomes, also inhibits lactate movement in SmAQP-expressing oocytes. In keeping with the substrate promiscuity of other aquaporins, SmAQP is shown here to be also capable of transporting water, mannitol, fructose and alanine but not glucose. Using immunofluorescent and immuno-EM, we confirm that SmAQP is localized in the tegument of adult worms. These findings extend the proposed functions of the schistosome tegument beyond its known capacity as an organ of nutrient uptake to include a role in metabolic waste excretion.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
|Dewey Decimal Classification:||570 Life sciences; biology|
|Deposited On:||16 Dec 2010 09:17|
|Last Modified:||12 Nov 2014 12:24|
|Publisher:||Public Library of Science (PLoS)|
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