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Updated: Jul 18, 2025
10:23
Lipid Droplet Isolation for Quantitative Mass Spectrometry Analysis
Published on: April 17, 2017
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LC3 conjugation to lipid droplets.
Mohyeddine Omrane1, Thomas J Melia2, Abdou Rachid Thiam1
1Laboratoire de Physique de L'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France.
Autophagy
|August 21, 2023
Summary
Macroautophagy/autophagy involves lipid droplet (LD) degradation. Our study reveals a non-canonical role for LDs in autophagy, where ATG3 on LDs facilitates LC3B lipidation and phagophore tethering for degradation.
Area of Science:
- Cell Biology
- Molecular Biology
- Autophagy Research
Background:
- Macroautophagy/autophagy and lipid droplet (LD) biology are closely interconnected.
- LDs are implicated in autophagosome formation, potentially supplying lipids and acting as assembly platforms.
- Shared proteins between LDs and autophagosomes suggest overlapping functions, but these remain unclear.
Purpose of the Study:
- To investigate the non-canonical role of lipid droplets (LDs) in autophagy.
- To elucidate the function of ATG3 and LC3B in the context of LDs during starvation.
Main Methods:
- Cell starvation experiments to observe protein localization.
- In vitro assays using purified and artificial LDs.
- Microscopy to analyze LD-LC3B interactions and autophagosome formation.
Main Results:
- Prolonged starvation induced ATG3 localization to large LDs, promoting LC3B lipidation.
- ATG3 was found to associate with LDs in vitro, binding conjugated Atg8-family proteins.
- LC3B on LDs acted as a tether, connecting phagophores to LDs for lysosome-mediated degradation.
Conclusions:
- Lipid droplets (LDs) possess a previously unrecognized non-canonical role in autophagy.
- LD-associated LC3B may serve as a crucial tethering factor, linking autophagosomes to LDs for degradation.
- Certain LD surfaces might function as lipidation sites for LC3B, facilitating autophagosome biogenesis.
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