Open AccessThe microneme protein MIC3 of Toxoplasma gondii is a secretory adhesin that binds to both the surface of the host cells and the surface of the parasite
Author(s) -
GarciaRéguet Nathalie,
Lebrun Maryse,
Fourmaux MarieNoëlle,
MercereauPuijalon Odile,
Mann Tara,
Beckers Cornelius J. M.,
Samyn Bart,
Van Beeumen Jozef,
Bout Daniel,
Dubremetz JeanFrançois
Publication year - 2000
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1046/j.1462-5822.2000.00064.x
Subject(s) - microneme , biology , toxoplasma gondii , bacterial adhesin , rhoptry , microbiology and biotechnology , apicomplexa , antibody , biochemistry , gene , genetics , virulence , plasmodium falciparum , malaria , immunology
Assay of the adhesion of cultured cells on Toxoplasma gondii tachyzoite protein Western blots identified a major adhesive protein, that migrated at 90 kDa in non‐reducing gels. This band comigrated with the previously described microneme protein MIC3. Cellular binding on Western blots was abolished by MIC3‐specific monoclonal and polyclonal antibodies. The MIC3 protein affinity purified from tachyzoite lysates bound to the surface of putative host cells. In addition, T. gondii tachyzoites also bound to immobilized MIC3. Immunofluorescence analysis of T. gondii tachyzoite invasion showed that MIC3 was exocytosed and relocalized to the surface of the parasite during invasion. The cDNA encoding MIC3 and the corresponding gene have been cloned, allowing the determination of the complete coding sequence. The MIC3 sequence has been confirmed by affinity purification of the native protein and N‐terminal sequencing. The deduced protein sequence contains five partially overlapping EGF‐like domains and a chitin binding‐like domain, which can be involved in protein–protein or protein–carbohydrate interactions. Taken together, these results suggest that MIC3 is a new microneme adhesin of T. gondii .