Download all files (5.49 MB)

Collection

Citation

Description:

This study investigated the incorporation of triacylglycerol droplets in the bilayers of giant unilamellar vesicles (GUVs) using four triacylglycerols and four phosphatidylcholines by confocal laser scanning microscopy. The triacylglycerol droplets were incorporated between the monolayer leaflets of the GUVs. Among the spherical droplets protruding on only one side of the bilayers, the droplets bound to the outer leaflets outnumbered those bound to the inner leaflets. The more frequent droplet binding to the outer leaflet caused transbilayer asymmetry in the droplet surface density. A vesicle consisting of a single-bilayer spherical segment and a double-bilayer spherical segment was also observed. The yield of these vesicles was comparable to or higher than that of the droplet-incorporating GUVs for many of the phosphatidylcholine–triacylglycerol combinations. In a vesicle consisting of single-bilayer and double-bilayer segments, most of the triacylglycerol droplets were localized on the outermost membrane surface along the segment boundary and in the double-bilayer segment. To rationalize the formation of these vesicle structures, we propose that the transbilayer asymmetry in the droplet surface density induces spontaneous curvature of the bilayer, with the bilayer spontaneously bending away from the droplets. Energy calculations performed assuming the existence of spontaneous curvature of the bilayer corroborated the experimentally determined membrane shapes for the vesicles consisting of unilamellar and bilamellar regions.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: Lipid droplets, Oil-water interface, Giant unilamellar vesicles, Phospholipids, Triacylglycerols, Spontaneous curvature, Fluorescence microscopy

Date published: 2024-05-31

Publisher: Elsevier BV

Journal:

• Biophysical Journal (ISSN: 00063495) vol. 123 issue. 13

Funding:

• Japan Society for the Promotion of Science 22K05179 (油水界面のリン脂質単分子膜：構造の定量分析と生体膜の 物理学)

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1016/j.bpj.2024.05.030

Related item:

Other identifier(s):

Contact agent:

Updated at: 2025-11-18 16:30:03 +0900

Published on MDR: 2024-07-04 16:30:26 +0900