An ER Protein Functionally Couples Neutral Lipid Metabolism on Lipid Droplets to Membrane Lipid Synthesis in the ER

Daniel F Markgraf, Robin W Klemm, Mirco Junker, Hans K Hannibal-Bach, Christer S. Ejsing, Tom A Rapoport

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption.
Original languageEnglish
JournalCell Reports
Volume6
Issue number1
Pages (from-to)44-55
DOIs
Publication statusPublished - 2014

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Membrane Lipids
Lipid Metabolism
Lipids
Proteins
Diglycerides
Triglycerides
Lipid Droplets
Substrate Cycling
Reticulum
Eukaryotic Cells
Transferases
Saccharomyces cerevisiae
Membrane Proteins
Switches
Degradation

Cite this

Markgraf, Daniel F ; Klemm, Robin W ; Junker, Mirco ; Hannibal-Bach, Hans K ; Ejsing, Christer S. ; Rapoport, Tom A. / An ER Protein Functionally Couples Neutral Lipid Metabolism on Lipid Droplets to Membrane Lipid Synthesis in the ER. In: Cell Reports. 2014 ; Vol. 6, No. 1. pp. 44-55.
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title = "An ER Protein Functionally Couples Neutral Lipid Metabolism on Lipid Droplets to Membrane Lipid Synthesis in the ER",
abstract = "Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption.",
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An ER Protein Functionally Couples Neutral Lipid Metabolism on Lipid Droplets to Membrane Lipid Synthesis in the ER. / Markgraf, Daniel F; Klemm, Robin W; Junker, Mirco; Hannibal-Bach, Hans K; Ejsing, Christer S.; Rapoport, Tom A.

In: Cell Reports, Vol. 6, No. 1, 2014, p. 44-55.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - An ER Protein Functionally Couples Neutral Lipid Metabolism on Lipid Droplets to Membrane Lipid Synthesis in the ER

AU - Markgraf, Daniel F

AU - Klemm, Robin W

AU - Junker, Mirco

AU - Hannibal-Bach, Hans K

AU - Ejsing, Christer S.

AU - Rapoport, Tom A

N1 - Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

PY - 2014

Y1 - 2014

N2 - Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption.

AB - Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption.

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DO - 10.1016/j.celrep.2013.11.046

M3 - Journal article

C2 - 24373967

VL - 6

SP - 44

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JO - Cell Reports

JF - Cell Reports

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