Asymmetric membranes

All plasma membranes - the outer "envelope" of every cell - are asymmetric. This means that the lipids on the inside and outside of the membrane are chemically different. Cells invest a great deal of energy in building and maintaining this asymmetry. Why they do this is the subject of intense research. Diseased cells often have an altered lipid pattern or, like cancer cells, lose their asymmetry. We may even be able to reverse pathological processes by targeting membrane asymmetry.

Our contribution

We want to find out how one side of the membrane influences the other and how membrane proteins react to this. This will enable us to better understand how signals are transmitted through the plasma membrane.

Our research shows that lipids can influence the opposite side of the membrane in different ways - for example, by packing them tighter or looser. In addition, asymmetric membranes often have a significantly higher bending strength than symmetric ones. If we measure the function of proteins in such membranes, we can link changes directly to these particular membrane properties.

Publications:

Schematic of a protein in an asymmetric membrane
Schematic representation of the effect of lateral pressure distribution in an asymmetric membrane on dimers of the outer membrane phospholipase (OmpLA) protein.
Design: P. Piller

Examples

Schema der Lipidkopplung in asymmetrischen Membranen ©Moritz Frewein
©Moritz Frewein
Different scenarios of the coupling of asymmetric membranes
From: Frewein et al, JMB (2022), License: (CC-BY 4.0 DEED).
Proteinaktivitätsmessungen
The membrane enzyme OmpLA works at different rates in symmetric and asymmetric membranes.
From: Pabst & Keller, TIBS (2024), License: (CC-BY 4.0 DEED).
Schema von FRET Messungen ©M. Kaltenegger (U. Graz)
©M. Kaltenegger (U. Graz)
Schematic representation of the measurement of protein-protein interactions.
Design: M. Kaltenegger