globosides

Globosides are a class of neutral glycosphingolipids (GSLs) characterized by a ceramide backbone linked to a neutral oligosaccharide chain that lacks sialic acid or sulfate groups. They belong to the globoserie of glycosphingolipids and typically contain three or more hexose residues in the carbohydrate moiety, assembled by specific glycosyltransferases in the Golgi apparatus.

A prominent subset includes globotriaosylceramide (Gb3, also known as ceramide trihexoside) and globotetraosylceramide (Gb4). These molecules are components of cellular membranes and are especially enriched in certain tissues. The carbohydrate chains often terminate in galactose residues and can serve as receptors for certain proteins and toxins; for example, Gb3 is the receptor for Shiga toxin produced by Shigella dysenteriae and some strains of Escherichia coli.

Biosynthesis and degradation follow the general glycosphingolipid pathways: ceramide is glycosylated stepwise in the Golgi to form neutral globo-series GSLs, which can be trimmed by lysosomal glycosidases. They contribute to membrane organization and cell–cell interactions and can influence signaling processes.

Clinical relevance: In Fabry disease, deficiency of the lysosomal enzyme alpha-galactosidase A leads to accumulation of Gb3 in vascular endothelium and other tissues, contributing to symptoms such as pain, kidney involvement, and cardiovascular issues. Abnormal globoside metabolism or accumulation has been observed in other contexts and can impact cellular function and disease progression.