title: The ceramide-enriched trans-Golgi compartments reorganize together with other parts of the Golgi apparatus in response to ATP-depletion.
abstract: In this study, the ceramide-enriched trans-Golgi compartments representing sites of synthesis of sphingomyelin and higher organized lipids were visualized in control and ATP-depleted hepatoma and endothelial cells using internalization of BODIPY-ceramide and the diaminobenzidine photooxidation method for combined light-electron microscopical exploration. Metabolic stress induced by lowering the cellular ATP-levels leads to reorganizations of the Golgi apparatus and the appearance of tubulo-glomerular bodies and networks. The results obtained with three different protocols, in which BODIPY-ceramide either was applied prior to, concomitantly with, or after ATP-depletion, revealed that the ceramide-enriched compartments reorganize together with other parts of the Golgi apparatus under these conditions. They were found closely associated with and integrated in the tubulo-glomerular bodies formed in response to ATP-depletion. This is in line with the changes of the staining patterns obtained with the Helix pomatia lectin and the GM130 and TGN46 immuno-reactions occurring in response to ATP-depletion and is confirmed by 3D electron tomography. The 3D reconstructions underlined the glomerular character of the reorganized Golgi apparatus and demonstrated continuities of ceramide positive and negative parts. Most interestingly, BODIPY-ceramide becomes concentrated in compartments of the tubulo-glomerular Golgi bodies, even though the reorganization took place before BODIPY-ceramide administration. This indicates maintained functionalities although the regular Golgi stack organization is abolished; the results provide novel insights into Golgi structure-function relationships, which might be relevant for cells affected by metabolic stress.
authors.affiliation: Department of Cell Biology and Ultrastructure Research, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria. claudia.meisslitzer-ruppitsch@meduniwien.ac.at
authors.forename: Claudia
authors.initials: C
authors.lastname: Meisslitzer-Ruppitsch
authors.forename: Clemens
authors.initials: C
authors.lastname: Röhrl
authors.forename: Carmen
authors.initials: C
authors.lastname: Ranftler
authors.forename: Josef
authors.initials: J
authors.lastname: Neumüller
authors.forename: Monika
authors.initials: M
authors.lastname: Vetterlein
authors.forename: Adolf
authors.initials: A
authors.lastname: Ellinger
authors.forename: Margit
authors.initials: M
authors.lastname: Pavelka
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D002518:Ceramides / Q000378:metabolism*; D055032:Electron Microscope Tomography; D042783:Endothelial Cells / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D008854:Microscopy, Electron; D013110:Sphingosine / Q000031:analogs & derivatives
chemical_list: D002518:Ceramides; C527864:N-(5-(5,7-dimethyl Bodipy)-1-pentanoyl)-erythrosphingosine; D000255:Adenosine Triphosphate; D013110:Sphingosine