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Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast

Transport and sorting of lipids must occur with specific mechanisms because the membranes of intracellular organelles differ in lipid composition even though most lipid biosynthesis begins in the ER. In yeast, ceramide is synthesized in the ER and transferred to the Golgi apparatus where inositolpho...

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Detalles Bibliográficos
Autores principales: Funato, Kouichi, Riezman, Howard
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2001
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150913/
https://www.ncbi.nlm.nih.gov/pubmed/11733544
http://dx.doi.org/10.1083/jcb.200105033
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author Funato, Kouichi
Riezman, Howard
author_facet Funato, Kouichi
Riezman, Howard
author_sort Funato, Kouichi
collection PubMed
description Transport and sorting of lipids must occur with specific mechanisms because the membranes of intracellular organelles differ in lipid composition even though most lipid biosynthesis begins in the ER. In yeast, ceramide is synthesized in the ER and transferred to the Golgi apparatus where inositolphosphorylceramide (IPC) is formed. These two facts imply that ceramide can be transported to the Golgi independent of vesicular traffic because IPC synthesis still continues when vesicular transport is blocked in sec mutants. Nonvesicular IPC synthesis in intact cells is not affected by ATP depletion. Using an in vitro assay that reconstitutes the nonvesicular pathway for transport of ceramide, we found that transport is temperature and cytosol dependent but energy independent. Preincubation of ER and Golgi fractions together at 4°C, where ceramide transport does not occur, rendered the transport reaction membrane concentration independent, providing biochemical evidence that ER-Golgi membrane contacts stimulate ceramide transport. A cytosolic protease-sensitive factor is required after establishment of ER-Golgi contacts.
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spelling pubmed-21509132008-05-01 Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast Funato, Kouichi Riezman, Howard J Cell Biol Article Transport and sorting of lipids must occur with specific mechanisms because the membranes of intracellular organelles differ in lipid composition even though most lipid biosynthesis begins in the ER. In yeast, ceramide is synthesized in the ER and transferred to the Golgi apparatus where inositolphosphorylceramide (IPC) is formed. These two facts imply that ceramide can be transported to the Golgi independent of vesicular traffic because IPC synthesis still continues when vesicular transport is blocked in sec mutants. Nonvesicular IPC synthesis in intact cells is not affected by ATP depletion. Using an in vitro assay that reconstitutes the nonvesicular pathway for transport of ceramide, we found that transport is temperature and cytosol dependent but energy independent. Preincubation of ER and Golgi fractions together at 4°C, where ceramide transport does not occur, rendered the transport reaction membrane concentration independent, providing biochemical evidence that ER-Golgi membrane contacts stimulate ceramide transport. A cytosolic protease-sensitive factor is required after establishment of ER-Golgi contacts. The Rockefeller University Press 2001-12-10 /pmc/articles/PMC2150913/ /pubmed/11733544 http://dx.doi.org/10.1083/jcb.200105033 Text en Copyright © 2001, The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Funato, Kouichi
Riezman, Howard
Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title_full Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title_fullStr Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title_full_unstemmed Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title_short Vesicular and nonvesicular transport of ceramide from ER to the Golgi apparatus in yeast
title_sort vesicular and nonvesicular transport of ceramide from er to the golgi apparatus in yeast
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150913/
https://www.ncbi.nlm.nih.gov/pubmed/11733544
http://dx.doi.org/10.1083/jcb.200105033
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