Cell membranes sustain phospholipid imbalance via cholesterol asymmetry

Milka Doktorova; Jessica L Symons; Xiaoxuan Zhang; Hong-Yin Wang; Jan Schlegel; Joseph H Lorent; Frederick A Heberle; Erdinc Sezgin; Edward Lyman; Kandice R Levental; Ilya Levental

doi:10.1016/j.cell.2025.02.034

Cell membranes sustain phospholipid imbalance via cholesterol asymmetry

Cell. 2025 Mar 26:S0092-8674(25)00270-3. doi: 10.1016/j.cell.2025.02.034. Online ahead of print.

Authors

Affiliations

¹ Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA; Department of Biochemistry and Biophysics, Stockholm University, Science for Life Laboratory, 17165 Solna, Sweden. Electronic address: milka.doktorova@dbb.su.se.
² Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
³ Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA.
⁴ Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, 17165 Solna, Sweden.
⁵ Department of Cellular and Molecular Pharmacology, TFAR, LDRI, UCLouvain, Avenue Mounier 73, B1.73.05, 1200 Brussels, Belgium.
⁶ Department of Chemistry, University of Tennessee Knoxville, Knoxville, TN 37916, USA.
⁷ Department of Physics and Astronomy, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
⁸ Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA. Electronic address: krl6c@virginia.edu.
⁹ Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA. Electronic address: il2sy@virginia.edu.

PMID: 40179882
DOI: 10.1016/j.cell.2025.02.034

Abstract

Membranes are molecular interfaces that compartmentalize cells to control the flow of nutrients and information. These functions are facilitated by diverse collections of lipids, nearly all of which are distributed asymmetrically between the two bilayer leaflets. Most models of biomembrane structure and function include the implicit assumption that these leaflets have similar abundances of phospholipids. Here, we show that this assumption is generally invalid and investigate the consequences of lipid abundance imbalances in mammalian plasma membranes (PMs). Using lipidomics, we report that cytoplasmic leaflets of human erythrocyte membranes have >50% overabundance of phospholipids compared with exoplasmic leaflets. This imbalance is enabled by an asymmetric interleaflet distribution of cholesterol, which regulates cellular cholesterol homeostasis. These features produce unique functional characteristics, including low PM permeability and resting tension in the cytoplasmic leaflet that regulates protein localization.

Keywords: cholesterol; lipid asymmetry; lipid diffusion; membrane packing; membrane structure; peripheral protein; permeability; phospholipid; plasma membrane; protein-membrane interactions.