Globotriaosylceramide is a

globoside Globosides are a sub-class of the lipid class glycosphingolipid with three to nine sugar molecules as the side chain (or R group) of ceramide. The sugars are usually a combination of ''N''-acetylgalactosamine, D-glucose or D-galactose. One ch ...

. It is also known as CD77, Gb3, GL3, and ceramide trihexoside. It is one of the few

clusters of differentiation The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophen ...

that is not a protein. It is formed by the alpha linkage of

galactose Galactose (, '' galacto-'' + ''-ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molec ...

lactosylceramide The Lactosylceramides, also known as LacCer, are a class of glycosphingolipids composed of a variable hydrophobic ceramide lipid and a hydrophilic sugar moiety. Lactosylceramides are found in microdomains on the plasma layers of numerous cells. ...

catalyzed by

A4GALT Lactosylceramide 4-alpha-galactosyltransferase is an enzyme that in humans is encoded by the ''A4GALT'' gene. The protein encoded by this gene catalyzes the transfer of galactose to lactosylceramide to form globotriaosylceramide Globotriaosylc ...

. It is metabolized by alpha-galactosidase, which hydrolyzes the terminal alpha linkage.

Clinical significance

Defects in the enzyme alpha-galactosidase lead to the buildup of globotriaosylceramide, causing Fabry's disease. The pharmaceutical drug

migalastat Migalastat, sold under the brand name Galafold, is a medication for the treatment of Fabry disease, a rare genetic disorder. It was developed by Amicus Therapeutics. The US Food and Drug Administration (FDA) granted it orphan drug status in 200 ...

enhances the function of alpha-galactosidase and is used to treat Fabry's. Globotriaosylceramide is also one of the targets of

Shiga toxin Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, expressed by genes considered to be part of the genome of lambdoid prophages. The toxins are named after Kiyoshi Shiga, who first described the bacterial ori ...

, which is responsible for pathogenicity of enterohemorrhagic ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...

'' (EHEC). The bacterial Shiga toxin can be used for targeted therapy of certain gastrointestinal cancers that express the receptor of the Shiga toxin. For this purpose a non-specific chemotherapeutic agent is conjugated to the B-subunit to make it specific. In this way only the tumor cells, but not healthy cells, should be destroyed during therapy.

References

Glycolipids {{biochem-stub