Membrane free-energy landscapes derived from atomistic dynamics explain nonuniversal cholesterol-induced stiffening.

Quantifying the energy necessary to remodel biological membranes is an essential step in understanding cell physiology. However, membrane bending involves both collective and atomic-level movements that are difficult to detect simultaneously. Here, atomically-detailed simulations fill a gap between those measurements. The results address a controversy that had recently emerged about the stiffness of cholesterol-rich membranes, which are ubiquitous in animal cells. The reason behind the surprising behavior of unsaturated lipids like DOPC is also revealed. Clearer connections are established between lipid chemistry and membrane mechanics, providing a more solid basis for future research on phenomena like cell trafficking or viral infection.