Title
Pre- and post-Golgi translocation of glucosylceramide in glycosphingolipid synthesis
Author
Halter, D.
Neumann, S.
van Dijk, S.M.
Wolthoorn, J.
de Mazière, A.M.
Vieira, O.V.
Mattjus, P.
Klumperman, J.
van Meer, G.
Sprong, H.
TNO Kwaliteit van Leven
Publication year
2007
Abstract
Glycosphingolipids are controlled by the spatial organization of their metabolism and by transport specificity. Using immunoelectron microscopy, we localize to the Golgi stack the glycosyltransferases that produce glucosylceramide (GlcCer), lactosylceramide (LacCer), and GM3. GlcCer is synthesized on the cytosolic side and must translocate across to the Golgi lumen for LacCer synthesis. However, only very little natural GlcCer translocates across the Golgi in vitro. As GlcCer reaches the cell surface when Golgi vesicular trafficking is inhibited, it must translocate across a post-Golgi membrane. Concanamycin, a vacuolar proton pump inhibitor, blocks translocation independently of multidrug transporters that are known to translocate short-chain GlcCer. Concanamycin did not reduce LacCer and GM3 synthesis. Thus, GlcCer destined for glycolipid synthesis follows a different pathway and transports back into the endoplasmic reticulum (ER) via the late Golgi protein FAPP2. FAPP2 knockdown strongly reduces GM3 synthesis. Overall, we show that newly synthesized GlcCer enters two pathways: one toward the noncytosolic surface of a post-Golgi membrane and one via the ER toward the Golgi lumen LacCer synthase. © The Rockefeller University Press.
Subject
Biology
Analytical research
carrier protein
concanamycin A
glucosylceramide
glycosphingolipid
lactosylceramide
protein FAPP2
proton pump inhibitor
article
cell surface
cellular distribution
controlled study
endoplasmic reticulum
Golgi complex
human
human cell
immunoelectron microscopy
in vitro study
priority journal
protein localization
protein synthesis
protein transport
Animals
Antigens, CD
Biological Transport
Brefeldin A
Carrier Proteins
Cattle
Cell Line
Cricetinae
Cricetulus
Endoplasmic Reticulum
Glucosylceramides
Glycosphingolipids
Glycosyltransferases
Golgi Apparatus
Humans
Intracellular Membranes
Lactosylceramides
Macrolides
Mice
Microscopy, Fluorescence
Models, Biological
Protein-Serine-Threonine Kinases
Proton Pump Inhibitors
Rats
To reference this document use:
http://resolver.tudelft.nl/uuid:b23bd369-3942-49f3-80c8-9b43a3a75806
DOI
https://doi.org/10.1083/jcb.200704091
TNO identifier
240242
ISSN
0021-9525
Source
Journal of Cell Biology, 179 (1), 101-115
Document type
article