The metabolic capacity of lipid droplet localized acyl-CoA synthetase 3 is not sufficient to support local triglyceride synthesis independent of the endoplasmic reticulum in A431 cells

Published on Jun 1, 2018in Biochimica et Biophysica Acta3.79
· DOI :10.1016/j.bbalip.2018.03.003
Margarete Poppelreuther6
Estimated H-index: 6
(Heidelberg University),
Simone Sander1
Estimated H-index: 1
(Heidelberg University)
+ 14 AuthorsJoachim Füllekrug28
Estimated H-index: 28
(Heidelberg University)
Abstract ACSL3 is the only long chain fatty acyl-CoA synthetase consistently found on growing and mature lipid droplets (LDs), suggesting that this specific localization has biological relevance. Current models for LD growth propose that triglycerides are synthesized by enzymes at the LD surface, with activated fatty acids provided by LD localized ACSL3, thus allowing growth independent of the ER. Here, we tested this hypothesis by quantifying ACSL3 on LDs from human A431 cells. RNAi of ACSL3 reduced the oleoyl-CoA synthetase activity by 83%, suggesting that ACSL3 is by far the dominant enzyme of A431 cells. Molar quantification revealed that there are 1.4 million ACSL3 molecules within a single cell. Metabolic labeling indicated that each ACSL3 molecule contributed a net gain of 3.1 oleoyl-CoA/s. 3D reconstruction of confocal images demonstrated that 530 individual lipid droplets were present in an average oleate fed A431 cell. A representative single lipid droplet with a diameter of 0.66 μm contained 680 ACSL3 molecules on the surface. Subcellular fractionation showed that at least 68% of ACSL3 remain at the ER even during extensive fatty acid supplementation. High resolution single molecule microscopy confirmed the abundance of cytoplasmic ACSL3 outside of LDs. Model calculations for triglyceride synthesis using only LD localized ACSL3 gave significant slower growth of LDs as observed experimentally. In conclusion, although ACSL3 is an abundant enzyme on A431 LDs, the metabolic capacity is not sufficient to account for LD growth solely by the local synthesis of triglycerides.
  • References (50)
  • Citations (6)
📖 Papers frequently viewed together
27 Citations
65 Citations
86 Citations
78% of Scinapse members use related papers. After signing in, all features are FREE.
#1Maya Schuldiner (Weizmann Institute of Science)H-Index: 35
#2Maria Bohnert (Weizmann Institute of Science)H-Index: 21
Abstract Lipid droplets (LDs) store lipids and hence serve as energy reservoir and as a source for building-blocks for the organelle membrane systems. LD biology therefore depends on tight communication with other organelles. The unique architecture of LDs, consisting of a neutral lipid core shielded by a phospholipid-monolayer, is however an obstacle to bulk-exchange of bilayer-bounded vesicles with other organelles. In recent years, it is emerging that contact sites, places where two organelle...
44 CitationsSource
#1Eric Leighton Klett (UNC: University of North Carolina at Chapel Hill)H-Index: 8
#2Shufen Chen (UNC: University of North Carolina at Chapel Hill)H-Index: 2
Last. Rosalind A. Coleman (UNC: University of North Carolina at Chapel Hill)H-Index: 58
view all 5 authors...
19 CitationsSource
The discovery by Dr. Constantine Londos of perilipin 1, the major scaffold protein at the surface of cytosolic lipid droplets in adipocytes, marked a fundamental conceptual change in the understanding of lipolytic regulation. Focus then shifted from the enzymatic activation of lipases to substrate accessibility, mediated by perilipin-dependent protein sequestration and recruitment. Consequently, the lipid droplet became recognized as a unique, metabolically active cellular organelle and its surf...
64 CitationsSource
#1Joachim Füllekrug (Heidelberg University)H-Index: 28
#2Margarete Poppelreuther (Heidelberg University)H-Index: 6
Long-chain fatty acyl-CoA synthetases (ACS) are a family of essential enzymes of lipid metabolism, activating fatty acids by thioesterification with coenzyme A. Fatty acyl-CoA molecules are then readily utilized for the biosynthesis of storage and membrane lipids, or for the generation of energy by s-oxidation. Acyl-CoAs also function as transcriptional activators, allosteric inhibitors, or precursors for inflammatory mediators. Recent work suggests that ACS enzymes may drive cellular fatty acid...
4 CitationsSource
Abstract Meeting the complex physiological demands of mammalian life requires strict control of the metabolism of long-chain fatty acyl-CoAs because of the multiplicity of their cellular functions. Acyl-CoAs are substrates for energy production; stored within lipid droplets as triacylglycerol, cholesterol esters, and retinol esters; esterified to form membrane phospholipids; or used to activate transcriptional and signaling pathways. Indirect evidence suggests that acyl-CoAs do not wander freely...
26 CitationsSource
#1Ditte Neess (University of Southern Denmark)H-Index: 10
#2Signe Bek (University of Southern Denmark)H-Index: 7
Last. Nils J. Færgeman (University of Southern Denmark)H-Index: 30
view all 5 authors...
Abstract Long-chain fatty acyl-CoA esters are key intermediates in numerous lipid metabolic pathways, and recognized as important cellular signaling molecules. The intracellular flux and regulatory properties of acyl-CoA esters have been proposed to be coordinated by acyl-CoA-binding domain containing proteins (ACBDs). The ACBDs, which comprise a highly conserved multigene family of intracellular lipid-binding proteins, are found in all eukaryotes and ubiquitously expressed in all metazoan tissu...
55 CitationsSource
Cuervo and colleagues find that perilipin proteins associated with lipid droplets are degraded by chaperone-mediated autophagy to facilitate recruitment of the lipolytic machinery to lipid droplets.
159 CitationsSource
#2Mark A Tsuchida (UCSF: University of California, San Francisco)H-Index: 1
Last. Nico Stuurman (UCSF: University of California, San Francisco)H-Index: 37
view all 6 authors...
µManager is an open-source, cross-platform desktop application, to control a wide variety of motorized microscopes, scientific cameras, stages, illuminators, and other microscope accessories. Since its inception in 2005, µManager has grown to support a wide range of microscopy hardware and is now used by thousands of researchers around the world. The application provides a mature graphical user interface and offers open programming interfaces to facilitate plugins and scripts. Here, we present a...
510 CitationsSource
#1Florian Wilfling (Yale University)H-Index: 8
#2Joel T. Haas (UCSF: University of California, San Francisco)H-Index: 18
Last. Robert V. Farese (UCSF: University of California, San Francisco)H-Index: 99
view all 4 authors...
Lipid droplets (LDs) are found in most cells, where they play central roles in energy and membrane lipid metabolism. The de novo biogenesis of LDs is a fascinating, yet poorly understood process involving the formation of a monolayer bound organelle from a bilayer membrane. Additionally, large LDs can form either by growth of existing LDs or by the combination of smaller LDs through several distinct mechanisms. Here, we review recent insights into the molecular process governing LD biogenesis an...
167 CitationsSource
#1Trisha J. Grevengoed (UCPH: University of Copenhagen)H-Index: 12
#2Eric L. KlettH-Index: 10
Last. Rosalind A. ColemanH-Index: 58
view all 3 authors...
Long-chain fatty acyl-coenzyme As (CoAs) are critical regulatory molecules and metabolic intermediates. The initial step in their synthesis is the activation of fatty acids by one of 13 long-chain acyl-CoA synthetase isoforms. These isoforms are regulated independently and have different tissue expression patterns and subcellular locations. Their acyl-CoA products regulate metabolic enzymes and signaling pathways, become oxidized to provide cellular energy, and are incorporated into acylated pro...
96 CitationsSource
Cited By6
#1Haarith Ndiaye (UCL: University College London)H-Index: 1
#2Jorlin Y Liu (UCL: University College London)
Last. Mark G. Waugh (UCL: University College London)H-Index: 16
view all 6 authors...
Long-chain fatty acyl CoA synthetases (ACSLs) activate fatty acids by CoA addition thus facilitating their intracellular metabolism. Dysregulated ACSL expression features in several cancers and can affect processes such a ferroptosis, fatty acid beta-oxidation, prostaglandin biosynthesis, steroidogenesis and phospholipid acyl chain remodelling. Here we investigate ACSL3 and ACSL4 expression in liver malignancies. The expression and subcellular localisations of the ACSL3 and ACSL4 isoforms in hep...
#1Xuejing Ma (La Trobe University)
Last. Pingsheng Liu (CAS: Chinese Academy of Sciences)H-Index: 40
view all 6 authors...
New strategies to decode the specific protein targeting mechanism on lipid droplet (LD) are urgently needed. Using adiposome, the LD binding of perilipin 2 (PLIN2), perilipin 3 (PLIN3), and adipose triglyceride lipase (ATGL) were studied. Scatchard analysis found that the binding of PLIN2 to the adiposome surface was saturable, pointing to a specific membrane binding partner. Phosphatidylinositol (PI) was found to inhibit PLIN2 binding while it did not impede PLIN3. Structural analysis combined ...
#1Yuanlang Wang (AAU: Anhui Agricultural University)
#2Wei Zhang (AAU: Anhui Agricultural University)H-Index: 1
Last. Yueyun Ding (AAU: Anhui Agricultural University)H-Index: 4
view all 13 authors...
Chinese indigenous pig and Western commercial pig breeds show different patterns of lipid metabolism, fat deposition, and fatty acid composition, and have become vitally important models of energy ...
Chronic inflammation contributes to cardiovascular disease. Increased levels of the inflammatory cytokine, TNF-alpha, are often present in conditions associated with cardiovascular disease risk, and TNF-alpha induces a number of pro-atherogenic effects in macrovascular endothelial cells, including expression of adhesion molecules and chemokines, and lipoprotein uptake and transcytosis to the subendothelial tissue. However, little is known about the roles of acyl-CoA synthetases (ACSLs), enzymes ...
1 CitationsSource
#1Jessica RoelandsH-Index: 4
#2Mathieu GarandH-Index: 2
Last. Damien ChaussabelH-Index: 46
view all 13 authors...
A potential role for the long-chain acyl-CoA synthetase family member 1 (ACSL1) in the immunobiology of sepsis was explored during a hands-on training workshop. Participants first assessed the robustness of the potential gap in biomedical knowledge identified via an initial screen of public transcriptome data and of the literature associated with ACSL1. Increase in ACSL1 transcript abundance during sepsis was confirmed in several independent datasets. Querying the ACSL1 literature also confirmed...
#1Veijo T. Salo (UH: University of Helsinki)H-Index: 6
#2Shiqian Li (UH: University of Helsinki)H-Index: 6
Last. Elina Ikonen (UH: University of Helsinki)H-Index: 46
view all 15 authors...
Summary Seipin is an oligomeric integral endoplasmic reticulum (ER) protein involved in lipid droplet (LD) biogenesis. To study the role of seipin in LD formation, we relocalized it to the nuclear envelope and found that LDs formed at these new seipin-defined sites. The sites were characterized by uniform seipin-mediated ER-LD necks. At low seipin content, LDs only grew at seipin sites, and tiny, growth-incompetent LDs appeared in a Rab18-dependent manner. When seipin was removed from ER-LD cont...
2 CitationsSource
#1Veijo T. Salo (UH: University of Helsinki)H-Index: 6
#2Elina Ikonen (UH: University of Helsinki)H-Index: 46
The formation of neutral lipid filled and phospholipid monolayer engulfed lipid droplets (LDs) from the bilayer of the endoplasmic reticulum (ER) is an active area of investigation. This process harnesses the biophysical properties of the lipids involved and necessitates cooperation of protein machineries in both organelle membranes. Increasing evidence suggests that once formed, LDs keep close contact to the mother organelle and that this may be achieved via several, morphologically distinct an...
5 CitationsSource
#1Tarik Exner (Heidelberg University)H-Index: 2
#2Carlo A. Beretta (Heidelberg University)H-Index: 5
Last. Joachim Füllekrug (Heidelberg University)H-Index: 28
view all 9 authors...
#1Tarik Exner (Heidelberg University)H-Index: 2
#2Inés Romero-Brey (Heidelberg University)H-Index: 16
Last. Joachim Füllekrug (Heidelberg University)H-Index: 28
view all 12 authors...
ABSTRACT Fatty acyl-CoA reductase 1 (Far1) is a ubiquitously expressed peroxisomal membrane protein that generates the fatty alcohols required for the biosynthesis of ether lipids. Lipid droplet localization of exogenously expressed and endogenous human Far1 was observed by fluorescence microscopy under conditions of increased triglyceride synthesis in tissue culture cells. This unexpected finding was supported further by correlative light electron microscopy and subcellular fractionation. Selec...
2 CitationsSource
#1Rosalind A. Coleman (UNC: University of North Carolina at Chapel Hill)H-Index: 58
5 CitationsSource