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Title: Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein

Abstract

Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified Caenorhabditis elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols is rich in fatty acid species obtained from the dietary Escherichia coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type and high-fat daf-2 mutant strains shows a very similar proteome in both strains, except that the most abundant protein in the C. elegans lipid droplet proteome, MDT-28, is relatively less abundant in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans. Finally, we confirmed the localization of one of the newly identified lipid droplet proteins, ACS-4. We found that ACS-4 localizes to the surface of lipid droplets in the C. elegans intestine and skin. This study bolsters C. elegansmore » as a model to study the dynamics and functions of lipid droplets in a multicellular organism.« less

Authors:
 [1];  [2];  [1];  [2];  [1]
  1. Washington State University, Pullman, WA (United States)
  2. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1198576
Alternate Identifier(s):
OSTI ID: 1209547
Grant/Contract Number:
P40 OD010440; R01 DK74114; P41 GM103493; AC05-76RL01830; AC05-76RL0 1830
Resource Type:
Journal Article: Published Article
Journal Name:
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
Additional Journal Information:
Journal Name: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids; Journal Volume: 1851; Journal Issue: 10; Journal ID: ISSN 1388-1981
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; C. elegans; Lipid droplets; DAF-2; Lipidomics; Proteomics

Citation Formats

Vrablik, Tracy L., Petyuk, Vladislav A., Larson, Emily M., Smith, Richard D., and Watts, Jennifer L. Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein. United States: N. p., 2015. Web. doi:10.1016/j.bbalip.2015.06.004.
Vrablik, Tracy L., Petyuk, Vladislav A., Larson, Emily M., Smith, Richard D., & Watts, Jennifer L. Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein. United States. doi:10.1016/j.bbalip.2015.06.004.
Vrablik, Tracy L., Petyuk, Vladislav A., Larson, Emily M., Smith, Richard D., and Watts, Jennifer L. Sat . "Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein". United States. doi:10.1016/j.bbalip.2015.06.004.
@article{osti_1198576,
title = {Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein},
author = {Vrablik, Tracy L. and Petyuk, Vladislav A. and Larson, Emily M. and Smith, Richard D. and Watts, Jennifer L.},
abstractNote = {Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified Caenorhabditis elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols is rich in fatty acid species obtained from the dietary Escherichia coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type and high-fat daf-2 mutant strains shows a very similar proteome in both strains, except that the most abundant protein in the C. elegans lipid droplet proteome, MDT-28, is relatively less abundant in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans. Finally, we confirmed the localization of one of the newly identified lipid droplet proteins, ACS-4. We found that ACS-4 localizes to the surface of lipid droplets in the C. elegans intestine and skin. This study bolsters C. elegans as a model to study the dynamics and functions of lipid droplets in a multicellular organism.},
doi = {10.1016/j.bbalip.2015.06.004},
journal = {Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids},
number = 10,
volume = 1851,
place = {United States},
year = {Sat Jun 27 00:00:00 EDT 2015},
month = {Sat Jun 27 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.bbalip.2015.06.004

Citation Metrics:
Cited by: 11works
Citation information provided by
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  • Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified C. elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols was rich in fatty acid species obtained from the dietary E. coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type andmore » high-fat daf-2 mutant strains shows a relative decrease of MDT-28 abundance in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans.« less
  • Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified Caenorhabditis elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols is rich in fatty acid species obtained from the dietary Escherichia coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type andmore » high-fat daf-2 mutant strains shows a very similar proteome in both strains, except that the most abundant protein in the C. elegans lipid droplet proteome, MDT-28, is relatively less abundant in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans. Finally, we confirmed the localization of one of the newly identified lipid droplet proteins, ACS-4. We found that ACS-4 localizes to the surface of lipid droplets in the C. elegans intestine and skin. This study bolsters C. elegans as a model to study the dynamics and functions of lipid droplets in a multicellular organism.« less
  • The mammalian Hippo pathway comprises mammalian Ste20-like kinases (MST1/2) and large tumor suppressor kinases (LATS1/2). LATS1/2, which are activated by MST1/2, phosphorylate a transcriptional co-activator, yes-associated protein (YAP), and induce the recruitment of YAP by 14-3-3 to cytoplasm, so that the TEAD-dependent gene transcriptions are turned off. Although the core components of the Hippo pathway are well conserved in metazoans, it has been discussed that Caenorhabditis elegans lacks YAP ortholog, we found that F13E6.4 gene encodes a protein that shows sequence similarities to YAP in the N-terminal TEAD-binding domain and in the WW domain. We designated this gene as yap-1.more » YAP-1 is widely expressed in various cells such as epithelial cells, muscles, hypodermal cells, gonadal sheath cells, spermatheca, and hypodermal cells. YAP-1 is distributed in cytoplasm and nuclei. wts-1 (LATS ortholog) and ftt-2 (14-3-3 ortholog) knockdowns cause nuclear accumulation of YAP-1, supporting that the subcellular localization of YAP-1 is regulated in a similar way as that of YAP. Heat shock also causes the nuclear accumulation of YAP-1 but after heat shock, YAP-1 translocates to cytoplasm. Knockdowns of DAF-21 (HSP90 ortholog) and HSF-1block the nuclear export of YAP-1 during this recovery. YAP-1 overexpression is beneficial for thermotolerance, whereas YAP-1 hyperactivity induced by wts-1 and ftt-2 knockdowns is deleterious on thermal response and yap-1 deficiency promotes health aging. In short, YAP-1 partially shares basal characters with mammalian YAP and plays a role in thermal stress response and healthy aging. - Highlights: ► We named Caenorhabditis elegans F13E6.4 gene yap-1 as a putative YAP homolog. ► The localization of YAP-1 is regulated by WTS-1 and FTT-2. ► YAP-1 is involved in healthy aging and thermosensitivity.« less
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