| Structural highlights
Function
[MIC4_TOXGO] Adhesin. Required for attachment of the parasite to the host cell prior to invasion.[1] [2]
Publication Abstract from PubMed
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.
Galactose recognition by the apicomplexan parasite Toxoplasma gondii.,Marchant J, Cowper B, Liu Y, Lai L, Pinzan C, Marq JB, Friedrich N, Sawmynaden K, Liew L, Chai W, Childs RA, Saouros S, Simpson P, Roque Barreira MC, Feizi T, Soldati-Favre D, Matthews S J Biol Chem. 2012 Mar 7. PMID:22399295[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Brecht S, Carruthers VB, Ferguson DJ, Giddings OK, Wang G, Jakle U, Harper JM, Sibley LD, Soldati D. The toxoplasma micronemal protein MIC4 is an adhesin composed of six conserved apple domains. J Biol Chem. 2001 Feb 9;276(6):4119-27. Epub 2000 Oct 26. PMID:11053441 doi:http://dx.doi.org/10.1074/jbc.M008294200
- ↑ Reiss M, Viebig N, Brecht S, Fourmaux MN, Soete M, Di Cristina M, Dubremetz JF, Soldati D. Identification and characterization of an escorter for two secretory adhesins in Toxoplasma gondii. J Cell Biol. 2001 Feb 5;152(3):563-78. PMID:11157983
- ↑ Marchant J, Cowper B, Liu Y, Lai L, Pinzan C, Marq JB, Friedrich N, Sawmynaden K, Liew L, Chai W, Childs RA, Saouros S, Simpson P, Roque Barreira MC, Feizi T, Soldati-Favre D, Matthews S. Galactose recognition by the apicomplexan parasite Toxoplasma gondii. J Biol Chem. 2012 Mar 7. PMID:22399295 doi:10.1074/jbc.M111.325928
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