Dynamic and structural properties of sphingolipids as driving forces for the formation of membrane domains

Sphingolipids are components of the membranes of all living organism cells. They are abundant in the plasma membranes and show a strong amphiphilic character, being constituted by a two-tail hydrophobic moiety, ceramide, and a very structurally variable hydrophilic headgroup. With ceramide inserted into the external leaflet of the plasma membrane, their hydrophilic headgroups protrude into the extracellular environment. Theoretical considerations about the peculiar physicochemical properties of sphingolipids and experimental data suggest that they play an active role in the biogenesis and maintenance of membrane lipid domains, zones of the membrane with reduced fluidity, where proteins involved in processes of cell signaling are segregated and can exert their properties.