title: Molecular signals in the trafficking of Toxoplasma gondii protein MIC3 to the micronemes.
abstract: The protozoan parasite Toxoplasma gondii is equipped with a sophisticated secretory apparatus, including three distinct exocytic organelles, named micronemes, rhoptries, and dense granules. We have dissected the requirements for targeting the microneme protein MIC3, a key component of T. gondii infection. We have shown that MIC3 is processed in a post-Golgi compartment and that the MIC3 propeptide and epidermal growth factor (EGF) modules contain microneme-targeting information. The minimal requirement for microneme delivery is defined by the propeptide plus any one of the three EGF domains. We have demonstrated that the cleavage of the propeptide, the dimerization of MIC3, and the chitin binding-like sequence, which are crucial for host cell binding and virulence, are dispensable for proper targeting. Finally, we have shown that part of MIC3 is withheld in the secretory pathway in a cell cycle-dependent manner.
authors.affiliation: UMR 5235 CNRS, Université de Montpellier 2, CP 107, Place Eugène Bataillon, 34090 Montpellier, France.
authors.forename: Hiba
authors.initials: H
authors.lastname: El Hajj
authors.forename: Julien
authors.initials: J
authors.lastname: Papoin
authors.forename: Odile
authors.initials: O
authors.lastname: Cérède
authors.forename: Nathalie
authors.initials: N
authors.lastname: Garcia-Réguet
authors.forename: Martine
authors.initials: M
authors.lastname: Soête
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dubremetz
authors.forename: Maryse
authors.initials: M
authors.lastname: Lebrun
mesh_terms: D000818:Animals; D019281:Dimerization; D006056:Golgi Apparatus / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*; D014122:Toxoplasma / Q000166:cytology / Q000378:metabolism*
chemical_list: C421382:MIC3 protein, Toxoplasma gondii; D021382:Protein Sorting Signals; D015800:Protozoan Proteins; C450759:TgM2AP protein, Toxoplasma gondii