Mammalian MemPrep establishes the lipid composition of ER membranes in HEK293T cells.

Mammalian ER membranes are primarily composed of phosphatidylcholine and monounsaturated glycerophospholipids, indicating a highly compressible bilayer.

• Why it matters: Understanding the lipid composition of ER membranes is crucial because it influences membrane dynamics and function, yet remains incompletely characterized in mammals.
• What they did: Using an optimized MemPrep workflow, the study performed high-confidence lipidomics on HEK293T cell ER membranes and ER tubule-enriched vesicles, analyzing their lipid profiles and protein features.
• The result: Findings reveal that ER tubules share a lipid composition with the general ER, and the physicochemical properties of ER lipids mirror those of ER-resident proteins, supporting a coordinated evolution of ER membrane components.