Arf1/COPI machinery acts directly on lipid droplets and enables their connection to the ER for protein targeting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 24497546.
- Also identified by DOI 10.7554/eLife.01607 and PMC identifier 3913038.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids, such as triacylglycerol (TG), as reservoirs of metabolic energy and membrane precursors. The Arf1/COPI protein machinery, known for its role in vesicle trafficking, regulates LD morphology, targeting of specific proteins to LDs and lipolysis through unclear mechanisms. Recent evidence shows that Arf1/COPI can bud nano-LDs (∼60 nm diameter) from phospholipid-covered oil/water interfaces in vitro. We show that Arf1/COPI proteins localize to cellular LDs, are sufficient to bud nano-LDs from cellular LDs, and are required for targeting specific TG-synthesis enzymes to LD surfaces. Cells lacking Arf1/COPI function have increased amounts of phospholipids on LDs, resulting in decreased LD surface tension and impairment to form bridges to the ER. Our findings uncover a function for Arf1/COPI proteins at LDs and suggest a model in which Arf1/COPI machinery acts to control ER-LD connections for localization of key enzymes of TG storage and catabolism. DOI: http://dx.doi.org/10.7554/eLife.01607.001.
Medical subject headings
- ADP-Ribosylation Factor 1
- COP-Coated Vesicles
- Coat Protein Complex I
- Endoplasmic Reticulum
- Lipid Droplets