title: Sphingolipids involvement in plant endomembrane differentiation: the BY2 case.
abstract: Sphingolipids play an essential role in the functioning of the secretory pathway in eukaryotic organisms. Their importance in the functional organization of plant cells has not been studied in any detail before. The sphingolipid synthesis inhibitor fumonisin B1 (FB1), a mycotoxin acting as a specific inhibitor of ceramide synthase, was tested for its effects on cell growth, cell polarity, cell shape, cell cycle and on the ultrastructure of BY2 cells. We used cell lines expressing different GFP-tagged markers for plant cell compartments, as well as a Golgi marker fused to the photoconvertible protein Kaede. Light and electron microscopy, combined with flow cytometry, were applied to analyse the morphodynamics and architecture of compartments of the secretory pathway. The results indicate that FB1 treatment had severe effects on cell growth and cell shape, and induced a delay in cell division processes. The cell changes were accompanied by the formation of the endoplasmic reticulum (ER)-derived tubular aggregates (FB1-induced compartments), together with an inhibition of cargo transport from the ER to the Golgi apparatus. A change in polar localization of the auxin transporter PIN1 was also observed, but endocytic processes were little affected. Electron microscopy studies confirmed that molecular FB1 targets were distinct from brefeldin A (BFA) targets. We propose that the reported effects of inhibition of ceramide biosynthesis reflect the importance of sphingolipids during cell growth and establishment of cell polarity in higher plant cells, notably through their contribution to the functional organization of the ER or its differentiation into distinct compartments.
authors.affiliation: Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Aubert
authors.forename: Jessica
authors.initials: J
authors.lastname: Marion
authors.forename: Claire
authors.initials: C
authors.lastname: Boulogne
authors.forename: Mickael
authors.initials: M
authors.lastname: Bourge
authors.forename: Susana
authors.initials: S
authors.lastname: Abreu
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bellec
authors.forename: Jean-Denis
authors.initials: JD
authors.lastname: Faure
authors.forename: Béatrice
authors.initials: B
authors.lastname: Satiat-Jeunemaitre
mesh_terms: D001693:Biological Transport, Active / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D037341:Fumonisins / Q000494:pharmacology; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D010088:Oxidoreductases / Q000037:antagonists & inhibitors; D030821:Plants, Genetically Modified; D013107:Sphingolipids / Q000378:metabolism*; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D037341:Fumonisins; D013107:Sphingolipids; D020126:Brefeldin A; C056933:fumonisin B1; D010088:Oxidoreductases; C108138:dihydroceramide desaturase