title: Differential targeting of dense granule proteins in the parasitophorous vacuole of Toxoplasma gondii.
abstract: The biosynthesis and fate of 4 different dense granule proteins of Toxoplasma gondii were studied with 3 monoclonal antibodies raised against tachyzoites and 1 polyclonal antibody raised against a recombinant protein. These proteins have the following molecular weights: 27 kDa (GRA 1), 28 kDa (GRA 2), 30 kDa (GRA 3) and 40 kDa (GRA 4). All four proteins were found in dense granules by immunoelectron microscopy; in T. gondii-infected cells, they were found in the vacuolar network but, in addition, GRA 3 was also detected on the parasitophorous vacuole membrane. Therefore, dense granule contents undergo differential targeting when exocytosed in the parasitophorous vacuole. Metabolic labelling and immunoprecipitation showed that GRA 2 and GRA 3 were processed from lower molecular weight precursors, and that GRA 2 and GRA 4 incorporated [3H] glucosamine and are thus likely to be glycosylated.
authors.affiliation: Unité 42 INSERM, Villeneuve d'Ascq, France.
authors.forename: A
authors.initials: A
authors.lastname: Achbarou
authors.forename: O
authors.initials: O
authors.lastname: Mercereau-Puijalon
authors.forename: A
authors.initials: A
authors.lastname: Sadak
authors.forename: B
authors.initials: B
authors.lastname: Fortier
authors.forename: M A
authors.initials: MA
authors.lastname: Leriche
authors.forename: D
authors.initials: D
authors.lastname: Camus
authors.forename: J F
authors.initials: JF
authors.lastname: Dubremetz
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D011233:Precipitin Tests; D015800:Protozoan Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D014122:Toxoplasma / Q000737:chemistry* / Q000648:ultrastructure; D014617:Vacuoles / Q000737:chemistry*; D014709:Vero Cells
chemical_list: D015800:Protozoan Proteins