Characterization of microneme proteins of Toxoplasma gondii

Achbarou, Abderrahim; Mercereau‐Puijalon, Odile; Autheman, J.M.; Fortier, B; Camus, Daniel; Dubremetz, Jean François

doi:10.1016/0166-6851(91)90182-6

Cited by 104 publications

(68 citation statements)

References 25 publications

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“…In addition, as the N-terminus of the protein is found 40 amino acids downstream of the predicted signal sequence cleavage site, this showed that the protein must be processed during its biosynthesis. This had indeed been described for MIC3 (Achbarou et al, 1991) and is a further confirmation of the identity of the cloned gene. Moreover, the predicted mass of the aa 67±359 deduced polypeptide (32.2 kDa) is in good agreement with the observed molecular mass of one mature subunit of MIC3 (38 kDa).…”

Section: Molecular Characterization Of the Cdna And Of The Gene Encodsupporting

confidence: 80%

“…As microneme proteins are likely to be involved in adhesion to host cell, we investigated whether the 90 kDa protein detected here was the MIC3 protein identified previously in our laboratory (Achbarou et al, 1991). Indeed, the MIC3 protein migrates in non-reducing gels as a 90 kDa band, which is a dimer of two 38 kDa polypeptides linked by disulphide bridges (Achbarou et al, 1991).…”

Section: Resultsmentioning

confidence: 76%

“…Indeed, the MIC3 protein migrates in non-reducing gels as a 90 kDa band, which is a dimer of two 38 kDa polypeptides linked by disulphide bridges (Achbarou et al, 1991). Figure 2A shows that the MIC3 protein (identified in lane 1 using a specific monoclonal antibody) comigrated with the 90 kDa cell-binding protein (lane 2).…”

Section: Resultsmentioning

confidence: 97%

“…Edman degradation of the purified MIC3 protein yielded a single N-terminal sequence. Achbarou et al (1991) had shown previously that MIC3 is made of two polypeptides of 38 kDa and respective isoelectric points of 6.75 and 6.7, both recognized by the same monoclonal antibody, and linked together by disulphide bridges. We therefore assume that MIC3 is a homodimer composed of two polypeptide chains differing in some post-translational modification resulting in a slightly different pHi.…”

Section: Molecular Structure Of Mic3mentioning

confidence: 99%

“…We have shown previously that MIC3 is located within the micronemes of extracellular tachyzoites (Achbarou et al, 1991). To investigate whether MIC3 is released during invasion, we developed a pulse-invasion protocol based on a low temperature blockade.…”

Section: Redistribution Of Mic3 From the Microneme To The Surface Of mentioning

confidence: 99%

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The 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

Lebrun²,

et al. 2000

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SummaryAssay 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.

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Section: Molecular Characterization Of the Cdna And Of The Gene Encodsupporting

confidence: 80%

Section: Resultsmentioning

confidence: 76%

Section: Resultsmentioning

confidence: 97%

Section: Molecular Structure Of Mic3mentioning

confidence: 99%

Section: Redistribution Of Mic3 From the Microneme To The Surface Of mentioning

confidence: 99%

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