Sulfaatide

Sulfatides are a class of glycosphingolipids that consist of a ceramide backbone linked to a sulfate ester of a galactose, most commonly 3'-sulfogalactosylceramide. They are part of the cerebroside family and are abundant in the outer leaflet of cellular membranes, particularly in the nervous system.

Biosynthesis of sulfatides occurs in the Golgi apparatus. Galactosylceramide is first formed by the transfer of galactose to ceramide. The galactose residue is then sulfated by a galactosylceramide sulfotransferase (cerebroside sulfotransferase) using the sulfate donor PAPS to yield sulfatide. This modification converts a neutral glycosphingolipid into an acidic, sulfated form.

Distribution and function of sulfatides are most prominent in the myelin sheath of the central and peripheral nervous systems, where they contribute to membrane stability, myelin integrity, and proper nerve conduction. They are enriched in lipid rafts and participate in protein–lipid interactions that affect signal transduction and cell adhesion. Sulfatides can also act as ligands for selectins, influencing leukocyte trafficking and inflammatory responses.

Clinical relevance centers on metabolism and storage. Defects in sulfatide degradation, notably deficiency of arylsulfatase A, lead to lysosomal accumulation of sulfatides and cause metachromatic leukodystrophy, a demyelinating disorder. Altered sulfatide metabolism has been studied in various demyelinating and neurodegenerative diseases, and sulfatide levels can be informative as biomarkers in certain clinical contexts.