title: Subcellular localization and dynamics of a digalactolipid-like epitope in Toxoplasma gondii.
abstract: Toxoplasma gondii is a unicellular parasite characterized by unique extracellular and intracellular membrane compartments. The lipid composition of subcellular membranes has not been determined, limiting our understanding of lipid homeostasis, control, and trafficking, a series of processes involved in pathogenesis. In addition to a mitochondrion, Toxoplasma contains a plastid called the apicoplast. The occurrence of a plastid raised the question of the presence of chloroplast galactolipids. Using three independent rabbit and rat antibodies against digalactosyldiacylglycerol (DGDG) from plant chloroplasts, we detected a class of Toxoplasma lipids harboring a digalactolipid-like epitope (DGLE). Immunolabeling characterization supports the notion that the DGLE polar head is similar to that of DGDG. Mass spectrometry analyses indicated that dihexosyl lipids having various hydrophobic moieties (ceramide, diacylglycerol, and acylalkylglycerol) might react with anti-DGDG, but we cannot exclude the possibility that more complex dihexosyl-terminated lipids might also be immunolabeled. DGLE localization was analyzed by immunofluorescence and immunoelectron microscopy and confirmed by subcellular fractionation. No immunolabeling of the apicoplast could be observed. DGLE was scattered in pellicle membrane domains in extracellular tachyzoites and was relocalized to the anterior tip of the cell upon invasion in an actin-dependent manner, providing insights on a possible role in pathogenetic processes. DGLE was detected in other Apicomplexa (i.e., Neospora, Plasmodium, Babesia, and Cryptosporidium).
authors.affiliation: Unité Mixte de Recherche 5168, Centre National de la Recherche Scientifique-Commissariat à l'Energie, Institut de Recherches en Technologies et Sciences pour le Vivant, 38058 Grenoble, France.
authors.forename: Cyrille
authors.initials: C
authors.lastname: Botté
authors.forename: Nadia
authors.initials: N
authors.lastname: Saïdani
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mondragon
authors.forename: Mónica
authors.initials: M
authors.lastname: Mondragón
authors.forename: Giorgis
authors.initials: G
authors.lastname: Isaac
authors.forename: Ernest
authors.initials: E
authors.lastname: Mui
authors.forename: Rima
authors.initials: R
authors.lastname: McLeod
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dubremetz
authors.forename: Henri
authors.initials: H
authors.lastname: Vial
authors.forename: Ruth
authors.initials: R
authors.lastname: Welti
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Cesbron-Delauw
authors.forename: Corinne
authors.initials: C
authors.lastname: Mercier
authors.forename: Eric
authors.initials: E
authors.lastname: Maréchal
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002736:Chloroplasts / Q000276:immunology / Q000378:metabolism; D000939:Epitopes / Q000276:immunology*; D038983:Galactolipids / Q000032:analysis / Q000276:immunology* / Q000378:metabolism*; D042541:Intracellular Space / Q000276:immunology* / Q000378:metabolism*; D013058:Mass Spectrometry; D016253:Microscopy, Immunoelectron; D011817:Rabbits; D051381:Rats; D018724:Spinacia oleracea / Q000276:immunology / Q000378:metabolism; D014122:Toxoplasma / Q000276:immunology* / Q000378:metabolism*
chemical_list: D000199:Actins; D000906:Antibodies; D000939:Epitopes; D038983:Galactolipids