A conserved family of proteins facilitates nascent lipid droplet budding from the ER into the cytosol

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Authors

• V Choudhary
• N Ojha
• A Golden
• WA Prinz

Abstract

Lipid droplets (LDs) are found in all cells and play critical roles in lipid metabolism. They contain a core of neutral lipids surrounded by a phospholipid monolayer. De novo LD biogenesis occurs in the endoplasmic reticulum (ER) but is not well understood. We imaged early stages of LD biogenesis using electron microscopy and found that nascent LDs form lens-like structures that are in the ER membrane, raising the question of how these nascent LDs bud from the ER as they grow. We found that a conserved family of proteins, fat storage-inducing transmembrane (FIT) proteins, is required for proper budding of LDs from the ER. Elimination or reduction of FIT proteins in yeast and higher eukaryotes causes LDs to remain in the ER membrane. Deletion of the single FIT protein in C. elegans is lethal, suggesting that LD budding is an essential process in higher eukaryotes. Our findings indicated that nascent LDs form lenses in the ER and that FIT proteins are necessary to promote proper budding of LDs from the ER.

Scientific Focus Area: Cell Biology

This page was last updated on Friday, March 26, 2021