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Galactose recognition by the apicomplexan parasite Toxoplasma gondii.

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Publication date 2012
Author Marchant Jan, Cowper Ben, Liu Yan, Lai Livia, Pinzan Camila, Marq Jean Baptiste, Friedrich Nikolas, Sawmynaden Kovilen, Liew Lloyd, Chai Wengang, Childs Robert A, Saouros Savvas, Simpson Peter, Roque Barreira Maria Cristina, Feizi Ten, Soldati-Favre Dominique, Matthews Stephen,
Project Study of factors governing the invasive and replicative modes in Apicomplexa
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Original article (peer-reviewed)

Journal The Journal of biological chemistry
Volume (Issue) 287(20)
Page(s) 16720 - 16733
Title of proceedings The Journal of biological chemistry
DOI 10.1074/jbc.M111.325928

Open Access

Type of Open Access Repository (Green Open Access)


Toxosplasma gondii is the model parasite of the phylum Apicomplexa, which contains numerous obligate intracellular parasites of medical and veterinary importance, including Eimeria, Sarcocystis, Cryptosporidium, Cyclospora and Plasmodium species. Members of this phylum actively enter host cells by a multi-step process with the help of microneme protein (MIC) complexes that play important roles in motility, host cell attachment, moving junction formation and invasion. Toxoplasma gondii (Tg)MIC1-4-6 complex is the most extensively investigated microneme complex which contributes to host cell recognition and attachment via the action of TgMIC1, a sialic acid-binding adhesin. Here, we report the structure of TgMIC4 and reveal its carbohydrate-binding specificity to a variety of galactose-containing carbohydrate ligands. The lectin is composed of six apple domains in which the fifth domain displays a potent galactose-binding activity, and which is cleaved from the complex during parasite invasion. We propose that galactose recognition by TgMIC4 masks the recognition of the parasite thereby providing protection from galectin-mediated activation of the host immune system.