Membrane Restructuring Following in situ Digestion of Ganglioside

Synchrotron radiation reflectometry was used to access the transverse structure of model membranes under the action of the human sialidase down to the Ångström length scale. Model membranes were designed to mimic the lipid composition of so-called Glycosphingolipids Enriched Micro domains (GEMs), which are membrane
platforms specifically enriched in cholesterol and sphingolipids.

Gangliosides, glycosphingolipids containing one or more sialic acid residues, are asymmetrically embedded in GEMs, in the outer membrane leaflet where gangliosides are claimed to interact directly with growth-factor receptors, modulating their activation and then the downstream intracellular signalling pathways. Thus, membrane dynamics and signalling could be strongly influenced by the activity of enzymes regulating the membrane ganglioside composition, including sialidases. Sialidase activity reveals to be a potential tool to control dynamically the structural properties of the membrane external leaflet of living cells, influencing both the morphology of the close environment and the extent of interaction among active molecules belonging to signalling platforms.