Sulfatide

Sulfatide is a sulfated glycosphingolipid, specifically a galactosylceramide bearing a sulfate group on the galactose. It is abundant in the myelin sheath of the central and peripheral nervous systems and is widely distributed in animal tissues. As an anionic lipid, sulfatide contributes to the negative surface charge of membranes and participates in the organization of membrane microdomains such as lipid rafts.

Chemically, sulfatide consists of a ceramide backbone linked to a single galactose, with a 3'-sulfate on the galactose; the ceramide portion varies in fatty acid chain length and saturation.

Sulfatide biosynthesis occurs in the Golgi, where cerebroside sulfotransferase transfers a sulfate from PAPS to galactosylceramide to form sulfatide. Lysosomal degradation is mainly carried out by arylsulfatase A, and deficiency of this enzyme causes accumulation of sulfatides in lysosomes.

Biologically, sulfatide participates in myelin maintenance, membrane organization, and axon-glial interactions. It also contributes to cell adhesion, signaling, and immune recognition in some contexts.

Clinically, loss of ARSA activity leading to sulfatide accumulation causes metachromatic leukodystrophy, a lysosomal storage disorder with progressive demyelination and neurological symptoms. Abnormal sulfatide metabolism has been investigated in other neurological and metabolic disorders.

Sulfatide is found most densely in nervous tissue but is also present in other organs such as the kidney. Analytical methods detect sulfatide levels in tissue or body fluids for research and, in some cases, diagnostic purposes.