Fat inclusions strongly alter membrane mechanics

Neutral lipids (NLs) are apolar oil molecules synthesized in the endoplasmic reticulum bilayer upon diverse biological stimuli. NLs synthesized are released in the hydrophobic core of the bilayer. At a critical concentration, NLs condense by phase separation and nucleate a lipid droplet (LD). After...

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Bibliographic Details
Published in:Biophysical journal 2021-02, Vol.120 (4), p.607-617
Main Authors: Santinho, Alexandre, Chorlay, Aymeric, Foret, Lionel, Thiam, Abdou Rachid
Format: Article
Language:English
Subjects:
Endoplasmic Reticulum
Life Sciences
Lipid Bilayers
Lipid Droplets
Membranes
Phospholipids
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Summary:Neutral lipids (NLs) are apolar oil molecules synthesized in the endoplasmic reticulum bilayer upon diverse biological stimuli. NLs synthesized are released in the hydrophobic core of the bilayer. At a critical concentration, NLs condense by phase separation and nucleate a lipid droplet (LD). After an LD forms, a fraction of NLs can be present in the bilayer but at a concentration below that of the nucleation. Here, we study whether and how the accumulation of NLs alters a lipid bilayer’s mechanical properties. In synthetic systems, we found that NLs proffer unusual bilayer stretching capacities, especially in the presence of negatively curved phospholipids. This impact becomes spectacular when an LD is contiguous with the bilayer and supplies it with NLs. The tested NLs markedly decrease the bilayer area expansion modulus and significantly increase lysis tension but had opposite effects on membrane bending rigidity. Our data unveil how NL molecules modify overall membrane mechanics, the alteration of which may be linked to pathologies or anticancer treatments targeting NLs.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2021.01.009