18. Mar. 2024
Cells are surrounded by semi-permeable membranes that protect them and regulate the passage of molecules in and out. A major component of these biological barriers is the asymmetric phospholipid bilayer. Scientists at CEITEC have now used computer simulations to show how membrane asymmetry affects the permeability of molecules.
Every cell in our body is separated from the outside environment by a protective barrier known as the plasma cell membrane, which is made up mainly of specific fats called lipids. These lipids are arranged in a bilayer structure. Interestingly, the composition of the two layers differs in the plasma membranes, creating what is called an asymmetric lipid composition. This asymmetry is crucial for the functionality of the cell and for the passage of molecules (including drugs) into the cell. Traditionally, simpler, symmetric models of these membranes have been used to study the passage of molecules across this barrier because they are easier to study.
A new study by Ladislav Bartoš and Robert Vácha from CEITEC Masaryk University shows the weakness of these simpler models. Using computer simulations, they compared the passage of small proteins and lipids through symmetric and asymmetric membranes. "We found that the difficulty of these molecules passing through asymmetric membranes often cannot be inferred from the passage through symmetric membranes. Specifically, these are cases where the molecules adsorb differently to different sides of the asymmetric membrane," says Ladislav Bartoš.
"This work highlights a gap in our understanding of how molecules cross cell membranes and suggests that more realistic models are needed to accurately predict this process. This is particularly important for the development and delivery of new drugs," concludes Robert Vácha.
The findings, which have been published in the Biophysical Journal, open up new perspectives for a better understanding of transport processes in cell membranes and have the potential to significantly influence the field of drug research and development.