Cholesterol modulates the bilayer structure of biological membranes in multiple ways. It
changes the fluidity, thickness, compressibility, water penetration and intrinsic curvature of
lipid bilayers. In multi-component lipid mixtures, cholesterol induces phase separations,
partitions selectively between different coexisting lipid phases, and causes integral
membrane proteins to respond by changing conformation or redistribution in the membrane.
But, which of these often overlapping properties are important for membrane fusion?—Here …