Gangliosider

Gangliosides are a class of glycosphingolipids characterized by the presence of one or more sialic acid residues in their oligosaccharide headgroup. They are components of cellular membranes, with high abundance in the nervous system, where they are concentrated in neuronal membranes and myelin.

They are categorized by the number of sialic acids and by the arrangement of sugars, with common monosialogangliosides such as GM1, GM2, and GM3, and disialogangliosides such as GD1a, GD1b, and GD2; higher-order GT and GQ series also exist. This naming reflects the number of sialic acids and the specific carbohydrate sequence.

Biosynthesis occurs in the Golgi apparatus by sequential glycosylation and sialylation of ceramide-containing precursors; mature gangliosides are transported to the outer leaflet of the plasma membrane, where they are enriched in lipid rafts and participate in signaling and cell–cell interactions.

Functions of gangliosides include involvement in cell recognition, modulation of receptor activity, and roles in neural development and plasticity. GM1, for example, binds the cholera toxin B subunit and is a widely studied ganglioside in neurobiology. Pathologically, anti-ganglioside antibodies are associated with autoimmune neuropathies such as Guillain-Barré syndrome, and alterations of ganglioside composition have been linked to aging and certain neurodegenerative conditions.