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Updated: Apr 1, 2026

Lipid Exchange Assay in Living Cells
Published on: March 21, 2025
No Evidence for Spontaneous Lipid Transfer at ER-PM Membrane Contact Sites
Elisa Merklinger1, Jan-Gero Schloetel2, Luis Spitta2,3
1Department of Membrane Biochemistry, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany. elisa.merklinger@uni-bonn.de.
Abstract:
Non-vesicular lipid transport steps play a crucial role in lipid trafficking and potentially include spontaneous exchange. Since membrane contact facilitates this lipid transfer, it is most likely to occur at membrane contact sites (MCS). However, to date it is unknown whether closely attached biological membranes exchange lipids spontaneously. We have set up a system for studying the exchange of lipids at MCS formed between the endoplasmic reticulum (ER) and the plasma membrane. Contact sites were stably anchored and the lipids cholesterol and phosphatidylcholine (PC) were not capable of transferring spontaneously into the opposed bilayer. We conclude that physical contact between two associated biological membranes is not sufficient for transfer of the lipids PC and cholesterol.
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